Ran out of room in last post...I wanted to add, Don't buy your copper fittings at the big box stores..Home Depot or Lowes. You'll pay 3 times as much...Some of the fittings I bought online were $3-4. HD or Lowes wanted $12-14 for the exact fittings....That will be a significant savings for you if you order them online. Also, make sure you put in plenty of unions. My old plumbing didn't have a single one. You couldn't take anything apart without cutting it out. These are just some of the things I can think of...
Tankless Water Heater For Floor Heat
- Thread starter 2Biz
- Start date
Buzzie8
Member
I read through most of the posts. I might have missed it, but you are heating 5 bays correct? I didn't see that posted but was assuming it from looking at your zone manifold.
I'm heating 4 bays. I also have a zone running through my trough. I figure if I'm going to be running floor heat, might as well heat the trough too. There is only a few degree's temperature drop in the return line from the trough, so it takes virtually nothing to heat it.
To finish off the floor heat boiler install, I thought I'd give you a performance update.
I put a Timer on the boiler that monitors "Boiler-On" time. Since it got down to 15° last night I thought it would be a good night to test for performance. In 15 hours (from 7:30 last night to 10:30 this morning) the boiler ran 11 hrs which is 73% of "On" time. I checked the slab surface temps with an infrared laser thermometer and the inside bays (no doors) read anywhere from 38° to 46°. The outside bay read 36° pretty much the entire slab. If I checked the aprons exiting the bays (shaded and not heated), the surface temps measured 15°. So this confirms my thermometer is pretty accurate.
To recap, I have the boiler set on 105°, average return temperature is 75°, and I have 90° tempered glycol going out to the bays. I doubt I'll be making any further adjustments since the ones I came up with is giving me adequate slab surface temps. Choking it down any more could possibly allow the bays to freeze over.
I put a Timer on the boiler that monitors "Boiler-On" time. Since it got down to 15° last night I thought it would be a good night to test for performance. In 15 hours (from 7:30 last night to 10:30 this morning) the boiler ran 11 hrs which is 73% of "On" time. I checked the slab surface temps with an infrared laser thermometer and the inside bays (no doors) read anywhere from 38° to 46°. The outside bay read 36° pretty much the entire slab. If I checked the aprons exiting the bays (shaded and not heated), the surface temps measured 15°. So this confirms my thermometer is pretty accurate.
To recap, I have the boiler set on 105°, average return temperature is 75°, and I have 90° tempered glycol going out to the bays. I doubt I'll be making any further adjustments since the ones I came up with is giving me adequate slab surface temps. Choking it down any more could possibly allow the bays to freeze over.
GoBuckeyes
Self-Serve and Automatics
It sounds like your system is working great 2Biz. It's definitely something I'll be thinking about this summer. 
I know there are lots of variables, however, we run our raypack boiler with a return stat temp of 65F and that works fine here in Cleveland. You may be able to turn your's down a bit. I'm sure it will depend on how high in the slab your lines are laid and other variables, but a slab temp of 46 seems like you have some wiggle room for adjustment.
I know there are lots of variables, however, we run our raypack boiler with a return stat temp of 65F and that works fine here in Cleveland. You may be able to turn your's down a bit. I'm sure it will depend on how high in the slab your lines are laid and other variables, but a slab temp of 46 seems like you have some wiggle room for adjustment.
Thanks for the input...I have the ball valve on my truck bay opened 100%. I have the rest of them opened based on distance from the ER and checking return temps with an infra red gun on each line. I tried to get them all set as close as possible temp wise. When I checked the outside bay temp the other morning, it was about 5°-10° colder (36°) than the covered bays. So I don't know if I can take the settings any lower?
What do you have your temp differential set at on your return line aquastat? I have mine set at 20°....Maybe this is where I can fine tune it even further, so there isn't as much temp swing? I'm all for saving more, but I'm pretty stoked with the difference this has made already. It doesn't scare me to death ($$$$) leaving it on now and its nice not having to fight with iced up bays.
What do you have your temp differential set at on your return line aquastat? I have mine set at 20°....Maybe this is where I can fine tune it even further, so there isn't as much temp swing? I'm all for saving more, but I'm pretty stoked with the difference this has made already. It doesn't scare me to death ($$$$) leaving it on now and its nice not having to fight with iced up bays.
GoBuckeyes
Self-Serve and Automatics
2Biz, it sounds like you've already done an "A+" on your set up. Like I said, there are lots of variables besides just the stat setting.
Too be honest, I'm not sure what the differential of the return stat is. I'm using whatever honeywells that Huron Valley would have spec'd. From memory, I want to say our air-stat, which turns on the pump and boiler is, is set at 35F and has a 1degree differential. At a few locations, I have eliminated this control and am using the second output of my Weepmiser.
The return-stat is set at 60 to 65F, controls the boiler's flame and has a 5degree differential (I will double check tomorrow). I can say with certainty, that it's no where close to 20 degrees. I will also check the burner settings to see what temperature range they are set at.
One thing that I dislike about using the weepmiser output is that it will sometimes bounce back and forth between my on/off setpoint. I may add a 5 minute off-delay timer to it so that my boiler doesn't cycle on and off like it does sometimes.
Too be honest, I'm not sure what the differential of the return stat is. I'm using whatever honeywells that Huron Valley would have spec'd. From memory, I want to say our air-stat, which turns on the pump and boiler is, is set at 35F and has a 1degree differential. At a few locations, I have eliminated this control and am using the second output of my Weepmiser.
The return-stat is set at 60 to 65F, controls the boiler's flame and has a 5degree differential (I will double check tomorrow). I can say with certainty, that it's no where close to 20 degrees. I will also check the burner settings to see what temperature range they are set at.
One thing that I dislike about using the weepmiser output is that it will sometimes bounce back and forth between my on/off setpoint. I may add a 5 minute off-delay timer to it so that my boiler doesn't cycle on and off like it does sometimes.
GoBuckeyes
Self-Serve and Automatics
2Biz, I checked at a few of my washes today and they're all pretty much the same. The Honeywell aquastat that we're using for the return temp is a Type T675A, which has an adjustable differential from 1 to 10. The ones I've checked are set to 3-4 degrees differential. The gas manifolds are set to the temperature range setting of 125F - 150F.
I had a chance to take a short video of my Floor Heat Boiler and install. The system was running when I shot the vid...So you can see why I have the lights to tell me when its running. You can't even hear it...
http://www.youtube.com/watch?v=BDunJiazJq0&feature=youtu.be
http://www.youtube.com/watch?v=BDunJiazJq0&feature=youtu.be
pitzerwm
Active member
Jesus, what a great neat setup. Mine always looked like crap, worked, but still crap.
Thanks! If anybody is in the same situation I was in with their old system wearing out, then this is definitely the route to go.
I made some additional changes that has saved even more on the gas usage. I changed the differential on the Aquastat from 20° down to 10°. Its kind of a balancing act. When you have the boiler temp set so low, you have to know at what return temp the boiler will always stay running. In my case it was about 75° incoming water temp. Any temp under that and the boiler stayed running constantly, it couldn’t heat the incoming glycol any further. So knowing this, I had to try to set the aquastat at a temperature that allows the boiler to cycle on and off and still keep the floors from freezing. That temp is about 70°-72°. So basically, the glycol temp in the loops average between 60° and 72° with the 10° differential. After several weeks making adjustments, I came up with this setting that allows the boiler to run about 50% of the time and still keep the floors from freezing. Time between cycles is about 30 minutes…. These adjustments were at about 25-30° outside temperature which is 90° of our freezing temps. Any temps colder than that should cause the boiler to stay on longer to compensate because of the lower incoming glycol temps. Hope all that made sense…
I made some additional changes that has saved even more on the gas usage. I changed the differential on the Aquastat from 20° down to 10°. Its kind of a balancing act. When you have the boiler temp set so low, you have to know at what return temp the boiler will always stay running. In my case it was about 75° incoming water temp. Any temp under that and the boiler stayed running constantly, it couldn’t heat the incoming glycol any further. So knowing this, I had to try to set the aquastat at a temperature that allows the boiler to cycle on and off and still keep the floors from freezing. That temp is about 70°-72°. So basically, the glycol temp in the loops average between 60° and 72° with the 10° differential. After several weeks making adjustments, I came up with this setting that allows the boiler to run about 50% of the time and still keep the floors from freezing. Time between cycles is about 30 minutes…. These adjustments were at about 25-30° outside temperature which is 90° of our freezing temps. Any temps colder than that should cause the boiler to stay on longer to compensate because of the lower incoming glycol temps. Hope all that made sense…
mjwalsh
6 bay SS w/laundromat
2Biz,
Based on our experience, both your system & presentation make very good sense!
We don't have a instant wall mount like yours yet; but we do have a closed loop boiler system that it does not have any danger of thermal shock from low inlet water temperature. In fact, there is a significant gain in efficiency by having as low as possible temperature to the final return. We have been told that it forces the boilers to produce more condensate which supposedly means more efficiency. I would mention it is a modular multipulse system of Hydropulses but they discontinued making those specific 150K BTU boilers in 2006 for reasons that escape us.
Question #1: We do not have that tube-chamber filled with limestone that you have to neutralize the acidic condensate going to the drain. Is that a requirement by your local code?
Question #2: In hindsight ... would you have sized a single larger supply pump to the Takagi rather than using two pumps?
mike
This is not a code requirement for our area. I read and saw online what the Acidic Condensate will do, even when the water runs accross the floor to a drain. It will eat away at the concrete! So its suppoesed to (Over time) eat or corrode a cast iron drain which is what I have...So better to be safe...Than sorry. It was easy to make...
On the pump size, At first I undersized the pump because I didn't know the boiler had such restriction. So after finding this out (basically learning how to read the flow chart for the boiler), I could have gone with a 2 stage pump to get the pressure. But the cost went up considerably. Plus it would have cost a lot more to operate. As it turns out, I am getting 40psi with the two Taco 013's in series which produces close to max flow through the boiler. They are rebuildable and only run on 2a of 120v each...I doubt you can get a 2 stage pump that will work that only uses 4a of 120v...So to answer your question, I did a little more research before making my mind up the second time around. This is what I based my decision on...Rebuildable pumps, cheap to operate, they are designed to pump heated water/glycol...Plus all three pumps are identical. Less to keep track of...
Maybe there is a better choice out there. But this is the biggest pump in its class with a cost that didn't break the bank...About $230 ea...
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wash4me
Member
I think you could save even more money by putting a bypass line from your supply to the bays and return from the bays manifold. Opening this valve would lower the temperature of the glycol going out to the bays. The lower temperature glycol will of course let the slab get colder and save gas. If you want to get fancy this could be on a solenoid valve with an aquastat that opens or closes it based on outdoor temperature.
Its really not needed. I have the boiler output temp set at 105°, once that mixes with the return from the bays, 90° temp glycol goes back out to the bay. I have the aquastat set to kick the boiler feed pumps off at 70°. The on-off cycle of the boiler is now 15 minutes on, 15 minutes off with a 10° temperature differential set on the aquastat.
With the aquastat and the ability to dial in the output of the demand heater in 5° increments, it virtually has limitless adjustments. It got down to 15° here over the weekend. With a 105° boiler output and the aquastat set to turn the boiler off at 70° return temps, it kept the weep from freezing on the bay floor. With an infrared temperature sensor, the surface of all my bay floors hovered between 35° and 45°...Checking the temps outside the bay 2feet from the heated floors registered 15°-17°....With these readings, I don't think I'm wasting any heat...
Essentially, I am already bypassing like you suggested. See post # 47. I have a primary - secondary system in place. The main loop circulates at 16 gpm. The boiler pumps pull from this main loop and puts 105° glycol back into the main loop at 6.6 gpm. This mixes with the return glycol and 90° glycol goes back out to the bay. If I want to lower the temps going back out to the bay, I decrease boiler temps. I can go down to 100° on the boiler. BUT I can go as high as 180° if I wanted. I hope I never have to go there!
With the aquastat and the ability to dial in the output of the demand heater in 5° increments, it virtually has limitless adjustments. It got down to 15° here over the weekend. With a 105° boiler output and the aquastat set to turn the boiler off at 70° return temps, it kept the weep from freezing on the bay floor. With an infrared temperature sensor, the surface of all my bay floors hovered between 35° and 45°...Checking the temps outside the bay 2feet from the heated floors registered 15°-17°....With these readings, I don't think I'm wasting any heat...
Essentially, I am already bypassing like you suggested. See post # 47. I have a primary - secondary system in place. The main loop circulates at 16 gpm. The boiler pumps pull from this main loop and puts 105° glycol back into the main loop at 6.6 gpm. This mixes with the return glycol and 90° glycol goes back out to the bay. If I want to lower the temps going back out to the bay, I decrease boiler temps. I can go down to 100° on the boiler. BUT I can go as high as 180° if I wanted. I hope I never have to go there!
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After a year under my belt with this new Demand Heater, I thought I would wake this thread up and give some latest details....I did some further experimenting and here is the results. I lowered the temperature from 33° to 32° (Seconday output on weepmizer) at which the whole system kicks on. I figured this could save several hours on each end in which the boiler wouldn't be running and save even more $$$...We'll, the next morning after making the change, the weep water was frozen on the floors. It hovered around freezing that night. So that did not work...33° on the weepmizer is the oiptimum setting to keep the bays from freezing.
I went to a website that records historical weather and calculated cost for the first 30 day billing cycle of NG. this winter
http://www.wunderground.com/history
From Nov 18th to Dec 18th (30 days) we had 14 days it didn't get above freezing in the daytime and 23 total nights the temps dropped below freezing. With 7 of those nights below 20° and a few nights temps were in the single digits...My NG bill was about $120-$130 higher than if we were just heating the ER. Although we don't normally have temps this cold, so it would have taken more NG to heat the er too. So the cost to heat the floors is on the high side. Given that, it doesn't worry me to just have it set to run whenever the temps call for it. Its not breaking the bank like the old system...
Oh and BTW...The system has worked perfectly for over a year now...Especially after getting it all dialed in. No maintenance...I would recommend a setup like this to anyone who is still running old non-condensing NG hogs...This setup works and works well. Comparing to what I originally had and running it the way I do now, I'm guessing payback to be one year. Especially with the temps we've been having. I couldn't have afforded running it if I still had the old system.
I went to a website that records historical weather and calculated cost for the first 30 day billing cycle of NG. this winter
http://www.wunderground.com/history
From Nov 18th to Dec 18th (30 days) we had 14 days it didn't get above freezing in the daytime and 23 total nights the temps dropped below freezing. With 7 of those nights below 20° and a few nights temps were in the single digits...My NG bill was about $120-$130 higher than if we were just heating the ER. Although we don't normally have temps this cold, so it would have taken more NG to heat the er too. So the cost to heat the floors is on the high side. Given that, it doesn't worry me to just have it set to run whenever the temps call for it. Its not breaking the bank like the old system...
Oh and BTW...The system has worked perfectly for over a year now...Especially after getting it all dialed in. No maintenance...I would recommend a setup like this to anyone who is still running old non-condensing NG hogs...This setup works and works well. Comparing to what I originally had and running it the way I do now, I'm guessing payback to be one year. Especially with the temps we've been having. I couldn't have afforded running it if I still had the old system.
This will probably be the last update to this thread unless there is a question posted. Sunday night through Tuesday night 1-5-14 thru 1-8-14, temps were as low as minus 12° to minus 15° with highs through the day of minus 2°. Even though I had the wash shut down, the floors stayed ice free with the weep flowing across the floors to the pits. I didn’t change any settings on the Takagi and was still getting 72-73° return temps from the zones. The boiler just stayed on longer than if temps were in the 20’s, but it was cycling on and off. This was with no doors on the bays with the bays facing North and South.
I did have a problem with my outside truck bay HP hose freezing, but I have a solution to fix that. Weeping cold water, my other three bays did just fine.
So I think I’ve tested this new demand heater from one end to the other and it meets/exceeds all and every expectation. If anybody has any questions, I’ll be happy to help. But I think I’ve just about covered everything in this thread you could possibly want to know.
Shouldn’t this thread be a “Sticky”!!!!????
I did have a problem with my outside truck bay HP hose freezing, but I have a solution to fix that. Weeping cold water, my other three bays did just fine.
So I think I’ve tested this new demand heater from one end to the other and it meets/exceeds all and every expectation. If anybody has any questions, I’ll be happy to help. But I think I’ve just about covered everything in this thread you could possibly want to know.
Shouldn’t this thread be a “Sticky”!!!!????