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Discussion Starter #1
I’m replacing my 21 year old Bradford white Combi-Core water heater/slab heater for my shop. It’s been reliable, and it has lasted longer than it’s supposed to have by about a factor of 2, so time for a mechanical room makeover.
The Combi-Core is kind of an energy sucker since it’s only about 80% efficient and has about a 90 gallon domestic water tank. It is 100K btu, but the heating loop HX is only rated for 50Kbtu, so it’s a little undersized for my shop. When it’s cold out it would be nice to get the slab water temp up to about 125-130 deg. I can only hit about 110. That’s with 180 deg water in the domestic tank. It’s just not the right unit for the application. I have to use space heaters in the dead of winter to keep up. I need more heat and less domestic HW (obviously with 90 gallons of 180 deg water)
I’m going to put in a Lockinvar Noble 199K btu boiler. They have a 10-1 turndown ratio and will do about 4gpm of dom HW
It dawned on me that my softener timer failed about 5 years ago, so I better get my water softened up so I don’t lime up my new HX. My old softener wasn’t a cycle on demand, so it used allot more salt than I liked.
So I’m looking for ideas on a new softener. Have the salt less ones gotten good enough for prime time? I do have a moderate amount of iron, and did have an iron filter. But all that was purchased/engineered before I drilled my well. Actual testing indicates that I don’t really need an iron filter, but I just have to make sure my softener can handle a little iron.
 

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I’m replacing my 21 year old Bradford white Combi-Core water heater/slab heater for my shop. It’s been reliable, and it has lasted longer than it’s supposed to have by about a factor of 2, so time for a mechanical room makeover.
The Combi-Core is kind of an energy sucker since it’s only about 80% efficient and has about a 90 gallon domestic water tank. It is 100K btu, but the heating loop HX is only rated for 50Kbtu, so it’s a little undersized for my shop. When it’s cold out it would be nice to get the slab water temp up to about 125-130 deg. I can only hit about 110. That’s with 180 deg water in the domestic tank. It’s just not the right unit for the application. I have to use space heaters in the dead of winter to keep up. I need more heat and less domestic HW (obviously with 90 gallons of 180 deg water)
I’m going to put in a Lockinvar Noble 199K btu boiler. They have a 10-1 turndown ratio and will do about 4gpm of dom HW
It dawned on me that my softener timer failed about 5 years ago, so I better get my water softened up so I don’t lime up my new HX. My old softener wasn’t a cycle on demand, so it used allot more salt than I liked.
So I’m looking for ideas on a new softener. Have the salt less ones gotten good enough for prime time? I do have a moderate amount of iron, and did have an iron filter. But all that was purchased/engineered before I drilled my well. Actual testing indicates that I don’t really need an iron filter, but I just have to make sure my softener can handle a little iron.
I too have been researching water treatment systems. Springwell Water Filters and Water Softener Systems - SpringWell Water Filtration Systems looks really good, although I have not compared their systems to others on the market.

We recently moved to a new home that has a well, that said I’m learning as I go.

Please keep us updated on your choices.
 

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Discussion Starter #3 (Edited)
I got around to doing this over the Labor Day Holiday. My wife committed to doing all of the animal chores for 4 days so I could focus. It was a long 4 days without water, but minus a little polishing, it is all working as designed.

Before.....
753878


When we did this room 21 years ago, they didn't have all the cool manifolds and such readily available. I was never really happy with how it turned out, and the floor heat was barely adequate.

After....
753880


I added a filter on the incoming main, redid all the piping completely using mostly 1inch L copper, and brass fittings where appropriate.
I installed a VFD for the well pump last year, and my larger pressure tank didn't work very good for that application, so I replaced the 65 gallon one with a 20 gallon one.
753881


753882


I should save allot on the energy bill since the old combi water heater was only 80% efficient (when new).
The new Lochinvar is 95% and 200K BTU. Plus it doesn't have a 70 gallon tank of 180 deg water sitting there.
The tankless does a faily good job of maintaining domestic water temp, but I think I'm going to install a thermostatic mixing valve anyway. The installation documents called for one, but I didn't listen.
I have to permanently wire it, install an outdoor air temp so it can adjust the heating water loop temperature as it gets colder out, and install a Tekmar 561 thermostat. That should be about it. Oh..and I want to redo the gas piping. I always hated that...it was kind of temporary 21 years ago :D
What a project. I'm glad its mostly over.
Total project cost was 7K (including a Milwaukee M18 bandsaw, and a M18 multi tool)😁
 

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We also went with a Lochinvar Noble. However it isn't that big. I want to say closer to 100K. Once our slab is warm, the thing barely ticks over.



We do have a separate tankless water heater we installed a few years ago that is a 199K unit.

We did go with the thermostatic mixing valve.



On top of that we also have a Hydro Separator. As well as stubs for a few more zones.



It is kind of hard to get a pic of everything because my mechanical room is pretty small. I wanted more garage space not more mechanical room space.

I find it interesting that you are shooting for water temps going to the slab so high. 125-130F in the slab would be pretty warm. Maybe your runs are really long or do you have poor insulation? I am trying to think how warm mine is and I would say 100 maybe. Before we had that gasket seal around my garage doors I had the heat on out there. Every time the wind would blow I would loose all my heat and the boiler was running quite a bit. I would be out there working and my feet would get pretty hot and sweaty. I wasn't too sure about this heated slab. It was nice for heat recovery but I was thinking about mats to stand on in work areas because it was really warm. Too warm. Once things were sealed up then the temps stabilized and the boiler didn't run nearly as much. This kept our slab temps much lower to maintain the called for temp and it was really comfortable out there. I was maintaining 65F all winter. It cost less to keep a 1200sqft garage at 65F than it cost me the previous year to heat our 200 sqft porch to about the same temp with electric baseboard heat. Heck that porch is now about 300 sqft and it is also kept warm by being between the heated house and garage. One of those stubs was there to heat the porch (now mud room) but we never bothered installing it because it would never run.
 
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Discussion Starter #5 (Edited)
We also went with a Lochinvar Noble. However it isn't that big. I want to say closer to 100K. Once our slab is warm, the thing barely ticks over.



We do have a separate tankless water heater we installed a few years ago that is a 199K unit.

We did go with the thermostatic mixing valve.



On top of that we also have a Hydro Separator. As well as stubs for a few more zones.



It is kind of hard to get a pic of everything because my mechanical room is pretty small. I wanted more garage space not more mechanical room space.

I find it interesting that you are shooting for water temps going to the slab so high. 125-130F in the slab would be pretty warm. Maybe your runs are really long or do you have poor insulation? I am trying to think how warm mine is and I would say 100 maybe. Before we had that gasket seal around my garage doors I had the heat on out there. Every time the wind would blow I would loose all my heat and the boiler was running quite a bit. I would be out there working and my feet would get pretty hot and sweaty. I wasn't too sure about this heated slab. It was nice for heat recovery but I was thinking about mats to stand on in work areas because it was really warm. Too warm. Once things were sealed up then the temps stabilized and the boiler didn't run nearly as much. This kept our slab temps much lower to maintain the called for temp and it was really comfortable out there. I was maintaining 65F all winter. It cost less to keep a 1200sqft garage at 65F than it cost me the previous year to heat our 200 sqft porch to about the same temp with electric baseboard heat. Heck that porch is now about 300 sqft and it is also kept warm by being between the heated house and garage. One of those stubs was there to heat the porch (now mud room) but we never bothered installing it because it would never run.
I may not need the 125 deg water. With my old system, I didn't have any flow meters on the manifolds, and I have found out over the years that the combi core heater that I had has an extremely high pressure drop through its heat exchanger. So I likely was not getting nearly the flow that I'm getting now (about 1.25 GPM per loop). That low flow might have been causing me to think I needed hotter water. I'm just gonna have to run it for a winter. It's for sure a whole new animal.
On design days I would usually run a space heater when I was working out there. There are 6 300 foot loops, and the building is 1800 sq ft with 14 foot sidewalls, and 2 12x12 overhead doors, just to give you an idea of the heat loss. I do get the snow melting about a foot outside the doors (which I kinda like). I have the tubing on top of 2inches of foam, and under 6 inches of sand, then 6 inches of concrete. So the floor temp evens out pretty good.
This is for the shop, but I think for the house I would like to do a separate HW heater and a smaller boiler like you did.
 

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I had a heating guy do all my work, design and install. I think my loops are shorter. I want to say they range from 180-250'. Most of the pics I have are from the install which is why a lot of it isn't fully hooked up in the photo.

I assume his writing on the board with feet measurements are the length of the run.







The manifold does control the flow. My understanding is this is more important when you have different length runs. My shortest run is about 70' shorter than my longest. If the manifold was just open with no flow control, the glycol would take the path of least resistance making the part of the slab where the short run is hot and the long run cold. I haven't noticed any part of the floor hotter or cooler than other areas. Like I mentioned, when I wasn't sealed up last Nov or so, the floor was really hot. We were out there doing electrical work and I didn't care for it. Once we had it sealed up then the slab temp dropped. I don't have a temp sensor in the slab, it works off of an air temp thermostat.

Did you also install the outside air temp sensor? I think mine completely shuts down the system when the outside air temp hits 70. We were running for a while and then out of the blue the heating guy shows up, I don't know maybe Feb or so. Things had been running fine. He kind of startled me as I happened to be in the garage and all of a sudden he walks through the access door. He said when he did the install he was missing a sensor and was installing it. This sensor was attached to the hot glycol output. He said it was there to keep it from short cycling and run more efficiently. I don't know it seems to short cycle more with it. Like I said, my boiler is much smaller but it barely runs and hits the cut off of 120F. I have the mixing valve that you said you didn't install yet and now that I think about it, I don't think I have ever seen temps higher than 90 going out from the manifold. Normally coming back around 70.

The garage like I said is 30x40 about 10.5' tall walls. 2x6 construction two 9'x9' and one 10'x9' overhead doors. There is 2" of foam board under the slab as well as on the inside of the block walls going down to the footings. I thought I had a pic of snow melt but I would say it is about the same. No snow close to a foot from the slab. We now have an apron as of yesterday so we will see if that changes anything.

I did just find this pic of most of the set up. Well no venting yet at this point or gas so not up and running. The white pex running up the ceiling in there goes over to the manifold and back which is on the other wall.

753890
 
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So since you had a tank water heater are you new to tankless? Or at least the idea of not having a tank? I will say there is a bit of a learning curve on expectations on it. For instance there are flow rates that have to be maintained or the tankless system will just shut down. This can be a problem with showers and some low flow shower heads. More so when people are used to setting a tank water heater to 160F so that when they mix it down to 100-110 in a shower the 40 gallons last long enough for a family to get through the showers. Well if you do this and take a cooler shower, maybe down in the 90-100 range with low flow heads you are mixing in so much water to drop the temp from lets say 160F (probably can't set it that high) to 90F that you drop below the min flow and the water heater cuts out. Then you get blasted with cold water. Or it cycles and you get blasted with hot then cold then hot water. Of course people assume it is that the tankless can't provide enough hot water as they can't make it any hotter but they don't understand that the fix is to lower the temp not raise it. This way if you are calling for 100F water and the water heater is providing 120F almost all the flow is going through the water heater and you are mixing in very little cold. This way it stays on. Now you have endless hot water. Also some shower mixing valves always mix in a certain amount of cold water for safety. We had to override this on our shower. The manual said how to do it for use cases like ours. We also ditched the low flow crap and ran a 1" PEX line to our shower. It helped that we were remodeling the main bath at the same time. We also ripped out 98% of the copper in the house and went with PEX. In doing that we also installed a Manibloc water manifold in the house. It is kind of like a breaker panel for water. You do individual runs to all the points of use. Then if you ever need to shut the water off at a point of use, I can go to the basement and do that without having to shut the entire house off or having to crawl behind a toilet or under a sink trying to turn a shutoff that will likely be stuck or worse yet break off on me.

It was a lot of work and a little learning how things were different but we love it in the end. A big part of why we had to go with the 199K tankless is because our ground water is pretty cold like you as well I imagine. In order to get the delta on the water that we needed at the needed flow rate we had to go with a really big unit. I want to say we run it at about 122F. I have a remote switch where I can bump it up or down as needed though.
 

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Discussion Starter #8 (Edited)
So since you had a tank water heater are you new to tankless? Or at least the idea of not having a tank? I will say there is a bit of a learning curve on expectations on it. For instance there are flow rates that have to be maintained or the tankless system will just shut down. This can be a problem with showers and some low flow shower heads. More so when people are used to setting a tank water heater to 160F so that when they mix it down to 100-110 in a shower the 40 gallons last long enough for a family to get through the showers. Well if you do this and take a cooler shower, maybe down in the 90-100 range with low flow heads you are mixing in so much water to drop the temp from lets say 160F (probably can't set it that high) to 90F that you drop below the min flow and the water heater cuts out. Then you get blasted with cold water. Or it cycles and you get blasted with hot then cold then hot water. Of course people assume it is that the tankless can't provide enough hot water as they can't make it any hotter but they don't understand that the fix is to lower the temp not raise it. This way if you are calling for 100F water and the water heater is providing 120F almost all the flow is going through the water heater and you are mixing in very little cold. This way it stays on. Now you have endless hot water. Also some shower mixing valves always mix in a certain amount of cold water for safety. We had to override this on our shower. The manual said how to do it for use cases like ours. We also ditched the low flow crap and ran a 1" PEX line to our shower. It helped that we were remodeling the main bath at the same time. We also ripped out 98% of the copper in the house and went with PEX. In doing that we also installed a Manibloc water manifold in the house. It is kind of like a breaker panel for water. You do individual runs to all the points of use. Then if you ever need to shut the water off at a point of use, I can go to the basement and do that without having to shut the entire house off or having to crawl behind a toilet or under a sink trying to turn a shutoff that will likely be stuck or worse yet break off on me.

It was a lot of work and a little learning how things were different but we love it in the end. A big part of why we had to go with the 199K tankless is because our ground water is pretty cold like you as well I imagine. In order to get the delta on the water that we needed at the needed flow rate we had to go with a really big unit. I want to say we run it at about 122F. I have a remote switch where I can bump it up or down as needed though.
I am new to owning a tankless, but I'm in the HVAC/Industrial controls business, so I've been working with the larger non residential HX's and boilers for decades. Low flow is not an issue for my old school fixtures. I'm running a temp of 125 now on the domestic, and it might be a little hot. I probably could bump it down to 122 like yours.

The Noble has a preheat mode that seems to work pretty good...it keeps the HX at about 120 deg or so, so the hot water delay is similar to a tank system. I will more than likely shut that feature off since I really don't need it for the shop. I usually am running a garden hose to fill a bucket or wash something with hot water so I can let it run for a little while until it produces HW.

I haven't installed the outside air sensor yet. The one that came with it was a little cheesy for my tastes, so I ordered a Johnson Controls one (its a 10K type 2 fenwal curve thermistor) in case you ever need to know:)
You may want to configure your boiler to produce cooler water as it warms up. Like 120 degrees at 0 deg outside, and 90 deg at 50 deg outside. That will also tame thing down a bit.

Your comment about the system loop sensor...
I found right away that mine runs way better without that sensor. Its hard to get the sensor installed where it senses the water quick enough. Maybe some thermal compound in the well would help. But, it appears with my system, that the boiler pump is always overflowing the loop pump anyway, so the loop supply is always equal to the boiler outlet temp. So I unhooked mine within 15 minutes of hooking it up...you may want to give that a try. If the Noble doesn't see the loop sensor, it automatically just controls to the outlet temp. An application where you would need the loop sensor is if your loop flow was greater than your boiler pump flow, then your loop supply temp would naturally be lower than the boiler outlet temp because you would be mixing return loop water. In that case the boiler would raise it's outlet temp to maintain the mixed supply temp.
 

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Our outdoor sensor happens to be right by the patio but it is up near the soffit so it isn't that noticeable and kind of blends in a bit. He wanted it up high and out of the sun. It is on our west wall. I guess the reading might be influenced by the siding heating up a bit being it is dark but it seems to run fine.



The two green PEX pipes in this shot are 1" ThermoPEX. It is a 70' run to my pole barn (shop) and I have a water to air heat exchanger that I need to hang out there. I am going to see if I can maintain the 36F that I like to keep it out there with this and then when I go out there to work and bump the heat I have one of those hanging natural gas shop heaters that can bring it up to a comfortable temp.



753943


One of the other stubs is to run over to the furnace and we want to put in a water to air heat exchanger in there to help heat the house. We need to replace our AC at a minimum and might even replace the furnace as it is just as old. I am not sure if something like this is big enough to actually heat the entire house all winter or if we will still need the furnace and use this for a little auxiliary heat. Maybe we should have done the 199K boiler. This is why there are two stubs ready for us before the thermostatic valve. For those two points of use (shop and house heat) we might increase the outlet temp to 160. The thermostatic valve then will tame the floor heat to where it is set now. 160F would be way to hot for the floors. In the pic below you can see the two electronic valves. One is for the garage floor heat and the other was for the mud room floor heat which I think we are skipping.

For that loop sensor, he just has it up against the copper outlet pipe with some of that grey pipe insulation over it. I wasn't sure if I could just disconnect it or if it needed to be disabled in the programming somewhere. I don't have a pic but I will reuse that pic from earlier (see below). It is about right in the middle of that horizontal pipe between the boiler outlet and the top inlet on the hydo separator. Right now with the hydro separator I think that the flow is much higher on the boiler loop because we only have the one zone right now so it just loops back to the boiler. That might change should the pole barn and the floor call for heat at the same time. Well and also the house at some point.

753946


For now, most of the flow is coming out the boiler outlet at 120F and circling back to the boiler at the Hydro separator. That heats up the inlet temp on the boiler. Then it shuts down when it starts seeing 120F glycol on the inlet. Then I will see anti cycling or something like that on the display. I get that this is saying it is preventing a short cycle and there is a waiting period where the pumps are still running but the programming is preventing the boiler for firing again even though the inlet temp has now dropped low enough. However there isn't much of a supply of hot water. There is some still looping from the boiler through the hydro separator but that isn't that big to be a big supply of hot glycol. Because there is the thermostatic valve, it does help limit how much hot is being pulled from the boiler loop a bit so the floor is still getting some heat even with the boiler off in blocking mode but it doesn't last long.

I have half been wondering if I should lower the outlet temp all together? At least until we expand the system to the additional zones. If the outlet temp was closer to the thermostatic valve setting, that would mean more heated glycol would flow through it and it would return more unheated glycol from the floor back to the hydro separator and boiler loop and keep the inlet temp on the boiler from hitting the outlet temp so quick and shutting down. Right now I would say the boiler fires, runs for a minute maybe two and then shuts down and goes into blocking for maybe 5 minutes. I don't have the system on right now but it wouldn't take much to turn it on and watch the temp gauge on the manifold to see what temp the thermostatc valve is set to. Then reprogram the boiler to something a lot closer. I want to say the input temp on the manifold is about 80-90F. You kind of mentioned this but also said doing it based on outside temp. On colder days (0F or so) run it at 120F and on warmer days (50F) run it at 90F. Help me understand this thought process. If the thermostatic valve is set to lets say 90F what is the point of running it at 120F on colder days? Why not just run say 100F? The floor still only sees 90F or so because of the thermostatic valve. While the outside temp might be colder that wouldn't matter much unless I fiddled with the thermostatic valve to put more heat in the slab, it is still going to only see 90F. Also it isn't like the slab is cooling down all that much as we set the air temp to 65F and leave it. Sure it isn't going to run much when it is in the 50F range outside but as the temps drop, the slab is going to stay warm. There is a lot of thermal mass there and when the air temp dropps, it is putting more heat back in there to maintain that slap temp. Most of our heat loss is from coming and going and opening a garage door but with this Covid stuff who knows how much that will happen. I have been in the office twice for a couple hours each time since March. I will say that is where this is nice. I can be out in the garage and my wife comes home. She may pull a cold vehicle into the garage but once that door is closed, it doesn't take long to be comfortable in there again. With the air temp set to 65 and it being winter I probably am just out there in jeans and a sweatshirt and plenty warm because I am doing stuff.
 

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Discussion Starter #10
Our outdoor sensor happens to be right by the patio but it is up near the soffit so it isn't that noticeable and kind of blends in a bit. He wanted it up high and out of the sun. It is on our west wall. I guess the reading might be influenced by the siding heating up a bit being it is dark but it seems to run fine.



The two green PEX pipes in this shot are 1" ThermoPEX. It is a 70' run to my pole barn (shop) and I have a water to air heat exchanger that I need to hang out there. I am going to see if I can maintain the 36F that I like to keep it out there with this and then when I go out there to work and bump the heat I have one of those hanging natural gas shop heaters that can bring it up to a comfortable temp.



View attachment 753943

One of the other stubs is to run over to the furnace and we want to put in a water to air heat exchanger in there to help heat the house. We need to replace our AC at a minimum and might even replace the furnace as it is just as old. I am not sure if something like this is big enough to actually heat the entire house all winter or if we will still need the furnace and use this for a little auxiliary heat. Maybe we should have done the 199K boiler. This is why there are two stubs ready for us before the thermostatic valve. For those two points of use (shop and house heat) we might increase the outlet temp to 160. The thermostatic valve then will tame the floor heat to where it is set now. 160F would be way to hot for the floors. In the pic below you can see the two electronic valves. One is for the garage floor heat and the other was for the mud room floor heat which I think we are skipping.

For that loop sensor, he just has it up against the copper outlet pipe with some of that grey pipe insulation over it. I wasn't sure if I could just disconnect it or if it needed to be disabled in the programming somewhere. I don't have a pic but I will reuse that pic from earlier (see below). It is about right in the middle of that horizontal pipe between the boiler outlet and the top inlet on the hydo separator. Right now with the hydro separator I think that the flow is much higher on the boiler loop because we only have the one zone right now so it just loops back to the boiler. That might change should the pole barn and the floor call for heat at the same time. Well and also the house at some point.

View attachment 753946

For now, most of the flow is coming out the boiler outlet at 120F and circling back to the boiler at the Hydro separator. That heats up the inlet temp on the boiler. Then it shuts down when it starts seeing 120F glycol on the inlet. Then I will see anti cycling or something like that on the display. I get that this is saying it is preventing a short cycle and there is a waiting period where the pumps are still running but the programming is preventing the boiler for firing again even though the inlet temp has now dropped low enough. However there isn't much of a supply of hot water. There is some still looping from the boiler through the hydro separator but that isn't that big to be a big supply of hot glycol. Because there is the thermostatic valve, it does help limit how much hot is being pulled from the boiler loop a bit so the floor is still getting some heat even with the boiler off in blocking mode but it doesn't last long.

I have half been wondering if I should lower the outlet temp all together? At least until we expand the system to the additional zones. If the outlet temp was closer to the thermostatic valve setting, that would mean more heated glycol would flow through it and it would return more unheated glycol from the floor back to the hydro separator and boiler loop and keep the inlet temp on the boiler from hitting the outlet temp so quick and shutting down. Right now I would say the boiler fires, runs for a minute maybe two and then shuts down and goes into blocking for maybe 5 minutes. I don't have the system on right now but it wouldn't take much to turn it on and watch the temp gauge on the manifold to see what temp the thermostatc valve is set to. Then reprogram the boiler to something a lot closer. I want to say the input temp on the manifold is about 80-90F. You kind of mentioned this but also said doing it based on outside temp. On colder days (0F or so) run it at 120F and on warmer days (50F) run it at 90F. Help me understand this thought process. If the thermostatic valve is set to lets say 90F what is the point of running it at 120F on colder days? Why not just run say 100F? The floor still only sees 90F or so because of the thermostatic valve. While the outside temp might be colder that wouldn't matter much unless I fiddled with the thermostatic valve to put more heat in the slab, it is still going to only see 90F. Also it isn't like the slab is cooling down all that much as we set the air temp to 65F and leave it. Sure it isn't going to run much when it is in the 50F range outside but as the temps drop, the slab is going to stay warm. There is a lot of thermal mass there and when the air temp dropps, it is putting more heat back in there to maintain that slap temp. Most of our heat loss is from coming and going and opening a garage door but with this Covid stuff who knows how much that will happen. I have been in the office twice for a couple hours each time since March. I will say that is where this is nice. I can be out in the garage and my wife comes home. She may pull a cold vehicle into the garage but once that door is closed, it doesn't take long to be comfortable in there again. With the air temp set to 65 and it being winter I probably am just out there in jeans and a sweatshirt and plenty warm because I am doing stuff.
The Noble doesn't look at the inlet temp to make any decisions. What it should be doing is firing to the loop temp, but if the OUTLET temp exceeds setpoint by 10 deg, then it shuts off. As long as there is still a space heating call, it will keep running the pumps, and will turn back on when the setpoint drops 10 deg below setpoint. If I were you, I would just disconnect the loop temp for now. The boiler will control much tighter. There is just too much of a delay in the loop sensor.
If I comprehended your previous posts correctly, you are currently only using it for the one space, so I would drop the temp as low as possible to do the job, and open the mixing valve up all the way. Until you have load diversity, the mixing valve isn't doing you any favors. With condensing boilers, you lose efficiency rapidly as the temperature goes up, so they really shine at temps less than 120. If you add water coils in the furnaces, try to size them for low temps. The Noble will be happy to fire at 160 deg (or even 190), but at that point you may have just as well bought a non condensing boiler. It's the really low return temps that these boilers like, so even if you were firing at 130 and had a 118 deg return temp, you would still be in the condensing range. But 120 supply and 108 return would be better yet.
That's where the outdoor air temp / supply water temp reset comes in....You set it up for using the lowest supply temp that gets the job done at a given outdoor air temp.
If 90 deg handles your floor in the dead of winter, then I would set that at the warmest, then go down to 80 or even 75 deg when it is say 50 deg outside.
Then you keep the boiler in it's sweet spot longer, and you get less short cycling and more even temps in the spaces.
Conventional boilers can't handle operating in this fashion because the low return temps and condensation will rot out the heat exchangers.
It seems like many installers still have the old design practices in their heads when they design modern condensing boiler systems.
 

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The Noble doesn't look at the inlet temp to make any decisions. What it should be doing is firing to the loop temp, but if the OUTLET temp exceeds setpoint by 10 deg, then it shuts off. As long as there is still a space heating call, it will keep running the pumps, and will turn back on when the setpoint drops 10 deg below setpoint. If I were you, I would just disconnect the loop temp for now. The boiler will control much tighter. There is just too much of a delay in the loop sensor.
You very well could be right. I did not program the boiler and only have watched what is on the display. I was assuming it was seeing the inlet temp rising to near the set point and since it wasn't actually heating anything at that point it was shutting down, but then the temp would quickly drop to the point where it should kick back in but it just shut off and then the display says something about bocking to prevent short cycling. You are probably right that it is on the outlet temp overshooting, either way it really isn't working very hard. That said there isn't much volume of hot water to keep the floor loop from dropping the temp pretty quick once it cuts out. Ever since he hooked up this loop sensor I have noticed it cycling a lot more. I imagine that isn't good for it. I was considering disconnecting it but I wasn't sure if it also needed to be disabled as well. Since you are saying I can just disconnect it, I will do that.

If I comprehended your previous posts correctly, you are currently only using it for the one space, so I would drop the temp as low as possible to do the job, and open the mixing valve up all the way. Until you have load diversity, the mixing valve isn't doing you any favors.
That is correct. There is only one zone currently hooked up. We have it installed so we can add 3 more zones but will likely only add 2 more at some point. I do have a 100K BTU water to air heat exchanger with fan for the pole barn but I haven't mounted it or hooked up the lines yet. I also was going to pull a thermostat wire through when I do that to control the zone.
With condensing boilers, you lose efficiency rapidly as the temperature goes up, so they really shine at temps less than 120. If you add water coils in the furnaces, try to size them for low temps. The Noble will be happy to fire at 160 deg (or even 190), but at that point you may have just as well bought a non condensing boiler. It's the really low return temps that these boilers like, so even if you were firing at 130 and had a 118 deg return temp, you would still be in the condensing range. But 120 supply and 108 return would be better yet.
So here is a thought. Maybe we shouldn't do this for reasons like the flow will go to the path of least resistance. For the two loops (zones) we will add at some point. One for the Pole Barn (shop) and one for the House. What would happen if we were to not have a thermostat on them? Basically whenever the garage in floor heat system is calling for heat, the glycol also flows out to the water to air exchanger in the pole barn and eventually the house. In the pole barn I ordered one of these.


I have a fan switch that is going to be installed with a probe inside the heater so once it detects warmth in there from the flow of glycol that it turns on the fan. Once the flow stops and the temp drops it cuts out.

The thought being as long as I am running heat to the floor, it also sends heat out to the shop. This will give me a greater delta or drop in temp from outgoing to return to the boiler. Possibly giving me 120 supply and 108 return like you said. So what if it might be hotter out there or colder. I still have the NG hanging furnace out in the pole barn to bridge any gap to maintain my min temp of 36F. If the floor heat in the garage runs more because it is colder or we are coming and going more, and the pole barn stays at lets say 40F so be it, the NG furnace won't run. It possibly would make my boiler more efficient and since the NG furnace isn't running it is kind of like free heat. The same might be true for the furnace in the house? Of course all this is crazy talk from someone that works in IT not HVAC so feel free to say it doesn't work this way and that is a terrible idea.

That's where the outdoor air temp / supply water temp reset comes in....You set it up for using the lowest supply temp that gets the job done at a given outdoor air temp.
If 90 deg handles your floor in the dead of winter, then I would set that at the warmest, then go down to 80 or even 75 deg when it is say 50 deg outside.
Then you keep the boiler in it's sweet spot longer, and you get less short cycling and more even temps in the spaces.
Conventional boilers can't handle operating in this fashion because the low return temps and condensation will rot out the heat exchangers.
It seems like many installers still have the old design practices in their heads when they design modern condensing boiler systems.
So ultimately, it sounds like I should disconnect that loop temp sensor. Then fire it up see what my thermostatic valve is set for by watching my inlet temp for my manifod is. I am all going off memory here as it hasn't been running since April or so. Also it isn't like I make a habit of sitting in a small mechanical room watching the digital display on my Noble Boiler. Lets say it is 90F going to the floor. Then set my outlet setpoint to 90F and then I can open up the thermostatic valve since it isn't really doing anything in my case with just one zone. That will up my flow and return cooler glycol back to the boiler and make it happier. While I installed and programmed our tankless water heater, I didn't do any of the setup or anything with this boiler. I didn't even build the garage, I hired a General Contractor that then subbed all the work like this floor heat stuff to a HVAC guy. Heck I know this boiler has a lockout password but I don't even know if I know what the password is or if it is set. I haven't touched the unit. When we the HVAC work went out to bid, we had in the requirements do have 1 zone and the ability to later add the zone for the in floor heat in the mud room and pole barn later. The HVAC guy stopped out and we were talking, he was trying to talk me into a Combi unit like what you got. He was going on and on about how I could replace my water heater. That is until I told him I installed a tankless water heater 3 years ago. Then he agreed to just go with a normal Noble boiler not the Combi. He then mentioned that since it can do 4 zones that we might as well prep it for the furnace in the house for a later upgrade. The additional cost was just two ball valves and using some of the scrap copper to have the stubs.

I guess the comment about running it at 160F is more likely from my background not in HVAC but from selecting and installing my tankless unit. I remembered that my tankless water heater is one of the less common ones in that it can be run in boiler mode where it will run at 160F. I have to open it up and move some jumpers but it will do it. I remember asking something about how he had the Noble running at 120F (from what I recall again) and I thought it was going to run at 160F. He made a comment along the lines of you would never want your floor that hot. That made sense. I guess I thought the point of the thermostatic valve was so that I can run 160F for the other stuff (pole barn and house heater) and yet also run the floor(s) at a much lower 90F or whatever makes sense there since it is mixing in colder return glycol from the return side of the floor loop.

What I do know is right now I am not getting much temp drop at all which is probably hurting my efficiency. It also is short cycling. Well it is trying to but the programming is preventing it. I need to see if I can get into the boiler settings to make changes and I need to disconnect that loop temp sensor. Or at least I think I know these things.
 

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I went out over lunch and found out a few things.

I don't know what the password is to get into the menu.

I disconnected the loop sensor.

I tried to run the boiler to see what the thermostatic valve is set to but couldn't because it is too warm outside. I cranked the heat to 75F and the thermostat was calling for heat but I think it is 70F outside so that is preventing the boiler from kicking on.

We are not that far apart and as you know, cooler temps are on the way so I can try it again then.
 

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Discussion Starter #13
The password is the last 4 digits of Jenny’s number😂
 

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5309.... I am on my way to hack into your boiler!!!!
 
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Do you know if they have a default password? It doesn't appear to be all 0s. I tried all 1s and the ultra secure 1234. I haven't looked through the manual but if he set a custom password on my boiler, I am going to kind of be pissed with him.
 
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Discussion Starter #16
The default is 5309
 
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That is funny. I am shocked they would use that but the engineer seems pretty cool. I wasn't sure if you were saying that is what you set yours to or if that was the default. I will try it a little later.
 

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Well that was my password.

Looks like mine is set to 120F and then cold day set to 150F. I will have to look at the manual to see what the threshold is for regular day vs cold day.
 

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Well that was my password.

Looks like mine is set to 120F and then cold day set to 150F. I will have to look at the manual to see what the threshold is for regular day vs cold day.
There are a couple parameters where the values for warm day and coldest day get set.
Then the heating setpoint will change in a linear fashion between the 2 points
See page 69 in the attached service manual.
Yours may be a little different, but it should be close on the heating parameters.
you could probably go 80 deg heating water at 50 deg outside, and 100deg at -20
Then tweak from there

You can download the manuals for your unit on the Lochinvar website.
 

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Thanks, I actually have the manuals hanging in the mechanical room so I can take a look at them. I do like having them on PDF so this is a good reminder. I keep all manuals in a folder on my Google drive so I always have access to them. I don't think I downloaded this one yet. Kind of forgot about it since I didn't install it.
 
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