A Slightly Special Radiant Floor Heat Installation
The system is powered by a second-floor installation of a Triangle Tube Prestige Solo 110 boiler. The boiler is coupled to a reverse indirect water heater (that serves its the main function as buffer tank) that feeds through 1 1/4” common piping, four manifold substations. The manifold substations will feed the in-slab basement loops, the plated staple-up first and second floors running 1200’-1800’ of ½ PEX per floor, and the final manifold feeding auxiliary panel radiators and a hydronically heated towel rack. Room temperature will be fine-tuned/controlled by thermoelectric actuator valves on the manifold. The two manifolds (for the second floor staple-up radiant loops and for the auxiliary panel radiators) are located next to the boiler, buffer tank, and the indirect water heater on the second floor while the manifolds for the first floor staple-up radiant loops and for the basement slab are located in the basement. The basement will eventually be dug out and radiant loops will lay inside the new perimeter-and-ground-insulated slab.
The first and second floor have 8 fully-plated staple-up radiant loops. The floor assembly is made up from ¾ hardwood flooring, ¼” underlayment, and two sheets of ¾” plywood subfloor – comprising 2½” of wood and glue assembly with an insulation value of R 2¼”. I could not find a way to mathematically verify that enough heat would enter the structure through the floor assembly before returning back to the buffer tank. The rule of thumb is a 1:5 ratio of the R value above the staple-up system to the insulation below to prevent back-loss. In this system we almost trippled the rule of thumb opting to go with R30 under the plated staple-up system. Also, driven by paranoia, it was decided that another manifold will be added for handling panel radiators – just in case the radiant floors will not provide the expected output during the design conditions.
"BEFORE"
"AFTER"
-------------------HEAT--LOAD--CALCULATIONS------------------
The heat load requirement for the structure is just under 45k BTUs (43281)
Floors/room breakdown is as follows:
Basement: 14333
zone1: 8600
zone2: 5733
First floor zones: 18554
zone3: 6680
zone4: 4619
zone5: 2817
zone6: 4438
Second floor zones: 10394
zone7: 5883
zone8: 1786
zone9: 2725
-----------------PUMP--SIZING--CALCULATIONS-----------------
The design deltaT is 20F.
Basement manifold GPM: 1.43
First floor manifold GPM: 1.86
Second floor manifold GPM: 1.04
Feet of head (longest loops 263 ft., assumed 2’ of head for the manifold)
~5.08 feet of head per manifold
Based off these all pumps were sized as taco 007 ECMs for each manifold, and return on the boiler.
--------------------------------------------------------------
Equipment on-hand:
> TriangleTube Prestige Solo 110 https://s3.amazonaws.com/triangletube.com/wp-content/uploads/2021/08/10180622/2019-06-Prestige-Solo-Installation_Maintenance-Manual.pdf
> Condensate pump
> 007 pumps vm1816-hy2-fc2h07 https://www.tacocomfort.com/documents/FileLibrary/007e_Catalog_100-150.pdf
> Taco ZVC406-4 zone controller https://www.tacocomfort.com/documents/FileLibrary/102-397.pdf
> Thermo2000’s Turbomax45 reverse indirect water heater/buffer tank with two extra taps
I could use component recommendations for just about everything else (or advice on what to avoid):
Need to source:
> Valves
> Air-mag-dirt separator
> Mixing valves for manifolds
> Manifolds
> Manifold actuator valves
> Buffer tank
> And everything else...
1. Quiz me on the design
2. Is the system I designed below missing any crucial or useful components?
3. What pressure issues should I be aware of due to the second-story boiler location e.g. exp tank pressure setting, fill-drain assembly placement
4. Copper or iron for the boiler piping?
5. To auto-fill or not? How should the system be connected to main for make-up water and how to prevent a major flood situation if there is a leak? Water sensing valve like Phyn?
6. To glycol or not to glycol in northern Ohio?
Comments
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Is this for a new install or a replacement? ..
1. Could you use a flooring system such as Viega Climate panel vs. a plated stapleup with 2 1/2" of material above it ?
2. How are you going to produce DHW during WWSD ?
3. Why is the BFP vent hooked up to the fill valve?
4. Reliefvalve on the Boiler side is Missing ?
5. DHW expansion Tank ?
6. As to autofill and Glycol: I would install a PIG with regular water and have a deironizer filter mediating the fill..I would also stay away from Glycol install Deironized water in conjunction with a sacrificial anode if the system allows for it.
7. I am a little concerned with the heat distribution manifolding as the circulating pumps may fight each other ?
8. I an guessing the TT still has it own Circ which is not shown in the drawing.
9. A service drain on the heating expansion tank would be advisable.
10. Could the boiler still be exchanged for a smaller one
Hope this helps.
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Your information is very well presented for this forum. It is a well thought out design, and is ambitious. As I see it, your system has 4 different water temperatures needed: 1.) domestic hot water, 2.) basement slab, 3. staple up floors, and 4.) panel rads. The reverse indirect 'buffer' tank is interesting. I'm not sure you need the buffering feature due to all of your well-designed radiant loops, and with the thermal mass of the basement floor. There is however the undesirable aspect of your domestic hot water being the same that goes through the radiant loops i.e. an "open" system. Maybe consider not doing the reverse indirect buffer tank and instead do an ordinary indirect tank just for DHW. You'd still have only 4 zones with different water temperatures required. You didn't mention the size of the tank. With your present design, the TT 110 really only needs to supply ONE water temp. for the DHW--hottest temp. The other 3 zones will be mixing their indiv. zone temps. down from that. I think it would be better for the TT 110 to do the 'management' with more constant circulation of the central heating zones, and have the DHW be its own priority zone as an indirect DHW tank.0
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How hot do you intend to run the boiler in order to satisfy the reverse indirect?
What are the design temps for the heating loops. Are you thinking of smart mixing valves and outdoor reset?
It seems like you are going to sacrifice combustion efficiency in order to prevent short cycling. That's not a great tradeoff.
If you did not already have the parts, I would suggest a boiler with 10-1 turndown and a small dedicated buffer tank. If I had to use part on hand, I think I would use the turbo max as a domestic priority and purchase a buffer tank. You could eliminate the mixing valves and run low, efficient boiler temps that way."If you can't explain it simply, you don't understand it well enough"
Albert Einstein0 -
psb75 said:
Your information is very well presented for this forum. It is a well thought out design, and is ambitious. As I see it, your system has 4 different water temperatures needed: 1.) domestic hot water, 2.) basement slab, 3. staple up floors, and 4.) panel rads. The reverse indirect 'buffer' tank is interesting. I'm not sure you need the buffering feature due to all of your well-designed radiant loops, and with the thermal mass of the basement floor. There is however the undesirable aspect of your domestic hot water being the same that goes through the radiant loops i.e. an "open" system. Maybe consider not doing the reverse indirect buffer tank and instead do an ordinary indirect tank just for DHW. You'd still have only 4 zones with different water temperatures required. You didn't mention the size of the tank. With your present design, the TT 110 really only needs to supply ONE water temp. for the DHW--hottest temp. The other 3 zones will be mixing their indiv. zone temps. down from that. I think it would be better for the TT 110 to do the 'management' with more constant circulation of the central heating zones, and have the DHW be its own priority zone as an indirect DHW tank.
The DHW and Heat are not sharing fluid in his design..
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Derheatmeister said:
Is this for a new install or a replacement? It is both, meaning that parts of the system, including the plated staple-up have already been completed.
1. Could you use a flooring system such as Viega Climate panel vs. a plated stapleup with 2 1/2" of material above it ? The plated staple-up system was chosen due to its low install cost and to protect the PEX tubing from the hardwood flooring install. And the loops are already installed.
2. How are you going to produce DHW during WWSD ? Good question! Not pictured is the aux tankless for DHW.
3. Why is the BFP vent hooked up to the fill valve? Great question! The diagram is in its auto-fill configuration. It simulates this assembly:
Did I fumble in its implementation into my system?
4. Relief valve on the Boiler side is Missing ? Absolutely correct! It has a relief vent built/included it coming off the top of the Prestige Solo110 unit. I will update the drawing with both the tankless water heater for the DHW (#3 above) and the relief valve on the boiler. Thanks!
5. DHW expansion Tank ? Hmmm, wouldn't the hot water just expand into the cold mains? Are you suggesting adding it before the mixing valve and after the reverse indirect water heater? I do not understand this problem, would you help me? I can add that I am strongly considering hot water recirculation...
6. As to autofill and Glycol: I would install a PIG with regular water and have a deironizer filter mediating the fill..I would also stay away from Glycol install Deironized water in conjunction with a sacrificial anode if the system allows for it. Your advice is to stay away from glycol (mimics my gut feeling, for what's it worth, as well). deironizer--->sacrificial_anode--->PIG--->fill_valve. Could you show me an example of this system? Being that glycol feeder (PIG) is not [usually?] connected to mains, would I manually dispense city water through a deironizer filter and collect it in a tank with a sacrificial anode and then, after some time manually walk it over and pour it into the glycol feeder?
7. I am a little concerned with the heat distribution manifolding as the circulating pumps may fight each other? I believe that the hydraulic separation offered by the buffer tank, essentially an oversized hydraulic separator, would be enough. For the peace of mind I could space the T's closer to create the 'closely spaced tee' situation as well.
8. I an guessing the TT still has it own Circ which is not shown in the drawing. The Triangle Tube Prestige Solo 110 is being fed by the circulator in the drawing.
9. A service drain on the heating expansion tank would be advisable. Do you mean a system that drains the tank (I believe the pressure tanks come with the drain) or do you mean a system that drains the tank to sewers (funnel and pipe to drain). Thanks!
10. Could the boiler still be exchanged for a smaller one
Hope this helps. No, unfortunately I am stuck with the boiler as it was purchased a long time ago
And yes, your post has made me consider a lot of different aspects! I'm looking forward to kick the ball around with you on at least a couple of those matters!0 -
Thank you for the response and compliments. It has taken me a while to design the system and I am glad my efforts show.psb75 said:Your information is very well presented for this forum. It is a well thought out design, and is ambitious. As I see it, your system has 4 different water temperatures needed: 1.) domestic hot water, 2.) basement slab, 3. staple up floors, and 4.) panel rads. The reverse indirect 'buffer' tank is interesting. I'm not sure you need the buffering feature due to all of your well-designed radiant loops, and with the thermal mass of the basement floor. There is however the undesirable aspect of your domestic hot water being the same that goes through the radiant loops i.e. an "open" system. Maybe consider not doing the reverse indirect buffer tank and instead do an ordinary indirect tank just for DHW. You'd still have only 4 zones with different water temperatures required. You didn't mention the size of the tank. With your present design, the TT 110 really only needs to supply ONE water temp. for the DHW--hottest temp. The other 3 zones will be mixing their indiv. zone temps. down from that. I think it would be better for the TT 110 to do the 'management' with more constant circulation of the central heating zones, and have the DHW be its own priority zone as an indirect DHW tank.
Reverse indirect basically operates like an on-demand tankless water heater with a claimed 99% efficiency rating. It is a closed system as the boiler water and DHW never mix. I realize that there would be some pushback with the reverse-indirect hot water tank acting as a buffer tank because they are uncommon, and because even likes such as Lochnivar are just now (2021) getting around to inserting them into their product lines. https://www.lochinvar.com/news-article/lochinvar-launches-reimagined-reverse-indirect-water-heater-for-continuous-hot-water/ The system I have designed originally was running a DHW priority loop used and indirect water, but 30 gallons was too small to provide 6 water-hungry occupants with hot water.
Old design:
I have some design constraints mainly when it comes to space, and the cost of the two parts vs one. I am planning to run the Pretige Solo 110 @ its condensing range which I believe, correct me if I am wrong, is 130F, but crank it up (is this possible?) during it's First Hour Use to satisfy Thermo2000's estimates on heating incoming 40F water to temperature in 7 seconds and 1/2F temp drop per hour: https://www.thermo2000.com/wp-content/uploads/produits/optimizer/THER-12004-DepliantTurboMax-EN-pages-Lr.pdf "Estimate based on: Boiler water supply at 180˚F and boiler water return at 160 ˚F; domestic cold water inlet at 40˚F and domestic hot water outlet at 140˚F"
My system does require a buffer tank, albeit a much smaller one: calculations were made to deduce that 20 gallons would suffice. Buffer tank also serves as a hydraulic separator in the system. Larger 48gal tank was chosen to give the reverse indirect water heater the stored mass it needs to produce enough flow for six people. I can provide the details I've used for the calculations for review.
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Zman, I am working on this problem. I am going to update the drawing today:Zman said:How hot do you intend to run the boiler in order to satisfy the reverse indirect?
What are the design temps for the heating loops. Are you thinking of smart mixing valves and outdoor reset?
It seems like you are going to sacrifice combustion efficiency in order to prevent short cycling. That's not a great tradeoff.
If you did not already have the parts, I would suggest a boiler with 10-1 turndown and a small dedicated buffer tank. If I had to use part on hand, I think I would use the turbo max as a domestic priority and purchase a buffer tank. You could eliminate the mixing valves and run low, efficient boiler temps that way.tomatooxides said:
Do you have any suggestions on how to temporarily raise temperature of the buffer tank/reverse-indirect? Maybe a controller?psb75 said:Your
I have some design constraints mainly when it comes to space, and the cost of the two parts vs one. I am planning to run the Pretige Solo 110 @ its condensing range which I believe, correct me if I am wrong, is 130F, but crank it up (is this possible?) during it's First Hour Use to satisfy Thermo2000's estimates on heating incoming 40F water to temperature in 7 seconds and 1/2F temp drop per hour: https://www.thermo2000.com/wp-content/uploads/produits/optimizer/THER-12004-DepliantTurboMax-EN-pages-Lr.pdf "Estimate based on: Boiler water supply at 180˚F and boiler water return at 160 ˚F; domestic cold water inlet at 40˚F and domestic hot water outlet at 140˚F"0 -
Consider a 2 pipe buffer tank: that way the buffer tank won't get in the way when you need to raise temperature, but when load is low it'll still extend run times.0
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The comment about the boiler Relief valve, expansion relief and the BFP vent being used as a feed are answered in this "redo" of your diagram in the red outlined areas. I also added one more isolation valve between the boiler system and the fill system. this will facilitate keeping the system operational in the event you need to service the BFP or the auto feed (Pressure Reducing) Valve.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Thank you Ed! That was very nice of youEdTheHeaterMan said:The comment about the boiler Relief valve, expansion relief and the BFP vent being used as a feed are answered in this "redo" of your diagram in the red outlined areas. I also added one more isolation valve between the boiler system and the fill system. this will facilitate keeping the system operational in the event you need to service the BFP or the auto feed (Pressure Reducing) Valve.
I understand! 0 -
I do not understand, please elaborate. Where would I feed the four manifolds from? Thanks!Hot_water_fan said:Consider a 2 pipe buffer tank: that way the buffer tank won't get in the way when you need to raise temperature, but when load is low it'll still extend run times.
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https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_17_na.pdf
looks like this! It lets you bypass the buffer tank during high demand, but use the full mass at low demand.1 -
Latest update based on Hot_water_fan's simple and powerful recommendation!
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OT: I am having trouble editing my post. Something about to-be-approved-by-administrator? Anyone know what's up with that?0
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Hot_water_fan, I've been pondering... Would this help in the reverse indirect tank's case with two taps as well? I've been trying to logic it out, and I think it does. But I wanted to know your opinion because you said 'buffer tank' not 'reverse indirect' and I think there is a difference as there are coils in the tank sucking up the heat. I'm not sure what you mean about the 'load as you may be referring to any number of things including the radiant floor and the reverse indirect coils0
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Awe man! That's brilliant! What a simple and yet powerful tip! Thank you!Hot_water_fan said:https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_17_na.pdf
looks like this! It lets you bypass the buffer tank during high demand, but use the full mass at low demand.0 -
@tomatooxides, if you post too many times within a short time period, your post may get held by our spam filters. I've sent it through. Please let me know if you have any questions.tomatooxides said:OT: I am having trouble editing my post. Something about to-be-approved-by-administrator? Anyone know what's up with that?
President
HeatingHelp.com0 -
I think piping from reverse indirect to tankless heater would be ideal since it lets the indirect maintain a slightly lower temperature but still provides the capacity you need, while the tankless can efficiently finish the job.1
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tomatooxides..The Updated drawing looks much better.
As to some of your questions:
1 Stapleup: We find that the heat transfer on a 2 1/2" Plated stapleup is not as good as a flooring system, it is also more labor intensive to install stapleup vs. a flooring system.
2. DHW during WWSD ? You got this under control in the updated drawing.
3. Why is the BFP vent hooked up to the fill valve ? You updated the drawing and it looks better
4. Relief valve on the Boiler side is Missing ? You updated the drawing and it looks better
5. DHW expansion Tank ? Nowadays to prevent cross contamination the city water suppliers have a check valve installed...For this reason we Install our Domestic expansion tanks on the cold water side of the Waterheater using a wall bracket such as the Flex Console/Flamco. In your case if you are using a Reverse Indirect in conjunction with a on demand there will be less thermal expansion so a smaller ST 5 most likely will do the job.
6. As to autofill and Glycol: When ever we can we fill our systems with deironized water as per the German Standard VDI 2035 in conjunction with this we install a sacrificial anode that has a magnet/auto air vent and also aids with the removal of sludge..Elysator makes the SorbOx ...Magnetic makes the HWR 10 Plus https://www.magnetic-online.de/ .
Also,In most cases we use a thermal expansion tank as our makeup water supply.. As we do not want to use regular water in our heating systems we also install a deironizer filter in the makeup water supply,
7. Looks like you may use a 2 pipe buffer tank setup...Use Short Stubby headers/Oversize the piping near the in/outlets of the Buffer tank and you should be fine.
8. Circulating pump: looks better
9. As you know Heating system expansion tanks need to be serviced ..The Bladder needs to be checked in a relief stage meaning the Bladder cannot have any system pressure against it then the charge is checked, We use the Webstone 41672 valve for this.
10. Using the Buffer tank will the 110 will help with the short cycling aspect during the shoulder seasons.1 -
One of the issues I am grappling with is that the heating water connections on the reverse indirect are sized 1 1/4 (same as my future manifold connections). 2" connections are only available on larger units that are too large for my install.
If I wanted to go with closely spaced 'generously sized headers' (I would size those at 2-2.5") -- I would run a bottleneck at my tank. Is this OK? If I bottleneck at the tank, would I still be able to reap the benefit of the 'generously sized headers' for the closely spaced tees?
Thanks!0
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