Heating large tanks with your gas hot water heater. Save 40% on energy cost!
Want2BS8ed
Active Member
In this case the heater is designed to draw combustion air from and exhaust outside. Same as the HVAC units in the basement (dual burner, DC blowers, high SEER a/c, scroll compressors, etc - all high efficiency units).
HVAC systems are serviced twice a year (spring and fall). Never thought about having them take a look at the water heater. Appreciate the suggestion.
M
If I already have a hot water circulating system on my home gas water heating system, my guess is all I need to do is have this exchanger plumbed in on some section of the heating loop (obviously nearest my sump in my fish cave thats under the house) along with the ball valve. I would likely also add one of our flow meters on both the aquarium and the hot water side. I would probably use a pump for circulating the aquarium water through this as opposed to the return. I think it will make things simpler in my particular case. Gotta get the parts ordered and then the time - winter is here!
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DBR_Reef
Active Member
Yeah, I was a little worried about that. The guy I bought mine from seemed fairly reputable, and I tested it (especially the welds) with hydrogen peroxide and salt, and didn't get any corrosion, so hopefully it will last. I actually had a really hard time finding a titanium heat exchanger made in the US in a reasonable size that is not custom made. All I found was Mexico and China. Do you know of a domestic source for them?
Coralfuture
Active Member
This is a really thorough video...I asked a water heater salesman about doing something like this and he told me he couldn't think of a way to do it. This video makes it look so easy...also my tank is 8ft from my water heater and I live in WI so this is a for sure in my future.
AlexG
Valuable Member
I am using the pex method for heating my 1600 gallon system with a ranco temp controller and a bronze re-circulation pump and my Apex acting as a backup over-temp controller. My radiant heating system runs everyday at least once even during the summer months so I am not really concerned about stagnant water in the loop but if it only ran a couple of times a week I would definitely have a concern about bacteria. Cost wise I was between $300-$400 for the pex system I installed largely because of the cost on the bronze re-circulation pump and the Ranco controller. I agree that using a hot water heater on larger tanks is more efficient and safer than using electric heaters.
I think the failure risk is on par with a pex system which is minimal with backup temp controllers and good plumbing connections.
What is your temperature delta between the water entering the heat ex-changer vs leaving the heat ex-changer when you use this method for heating?
I think the failure risk is on par with a pex system which is minimal with backup temp controllers and good plumbing connections.
What is your temperature delta between the water entering the heat ex-changer vs leaving the heat ex-changer when you use this method for heating?
Sea MunnKey
Valuable Member
"Smart" folks, plenty are here ... 
(Does that sound like Yoda speaking?)
(Does that sound like Yoda speaking?)
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DBR_Reef
Active Member
If a pex system is carefully designed I’m sure it could be just as low a risk- I would just want to make sure all connections were made outside the sump. And have daily flushing like you do. I still like the compactness of the ti heat exchanger.
I didn’t really measure delta accurately, as I realized as I was taking it that I needed flow rate to do anything with it, but it may be around 2 degrees F
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DBR_Reef
Active Member
A hot water heater could definitely be used only to heat a tank (I know of several people who use setups like this), but you would probably want to use a on demand heater, as the cost of having a tank hw heater idle is significant
In this case Terance I would add the exchanger into the loop and use the pump and valve on your aquarium water side. That is, you exchanger is always hot and you vary the water flow through the exchanger.
I also use a gas water heater, with electric heaters as backup. I use an in sump Titanium coil (1/3HP). My setup as follows.
Hardware:
Hardware:
- Apex Controller
- In sump Ti coil. (pictured below)
- STC-1000 Temperature Controller.
- Taco 007-SF5 Stainless Pump (w/valves)
- Misc. pex valves, fittings, and stainless swagelock adaptors.
- Temperature controller used to as backup. It will cut power to the recirculating pump when it exceeds the temp setpoint. Relay is wired in series with the pump. Controller is never powered off.
- Apex controls the recirculating pump. After 0.1F increase in temperature, the recirculating pump shuts off. The pump needs ~2.5mins to heat the water 0.1F. After the pump shuts off, my temp continues to increase 0.8F. This is a function of my tank volume (~140g), coil size, and ambient temperature.
- The pump needs to stay off for minimum of 30mins before turned on again (Apex)
- The temp needs to be below setpoint for 1min before turning on the pump (Apex)
- Turn the pump on 2x/day for 1min to circulate water. After 1min, the hot water has not reached the Ti coil yet. This prevents stagnant water when not used during the summer. I do not purge the system, but have fittings installed if necessary.
- Misc. overtemp/undertemp emails & text message alerts (Apex)
SpartaReef
Active Member
Following
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DBR_Reef
Active Member
Well that heat exchanger is probably a better way to go- no worries about detritus buildup in the heat exchanger affecting return pump flow. how come I couldn’t find that when I was looking- could have saved $100. How is the coil holding up?I also use a gas water heater, with electric heaters as backup. I use an in sump Titanium coil (1/3HP). My setup as follows.
Hardware:
Controls:
- Apex Controller
- In sump Ti coil. (pictured below)
- STC-1000 Temperature Controller.
- Taco 007-SF5 Stainless Pump (w/valves)
- Misc. pex valves, fittings, and stainless swagelock adaptors.
Side Note. I take the hot water from our kitchen sink, but return the hot water directly to the water heater. Anytime the recirculating pump turns on, we have instant hot water at our kitchen sink and dishwasher. No basement and all of the pex tubing is run in the crawlspace from tank to kitchen/garage.
- Temperature controller used to as backup. It will cut power to the recirculating pump when it exceeds the temp setpoint. Relay is wired in series with the pump. Controller is never powered off.
- Apex controls the recirculating pump. After 0.1F increase in temperature, the recirculating pump shuts off. The pump needs ~2.5mins to heat the water 0.1F. After the pump shuts off, my temp continues to increase 0.8F. This is a function of my tank volume (~140g), coil size, and ambient temperature.
- The pump needs to stay off for minimum of 30mins before turned on again (Apex)
- The temp needs to be below setpoint for 1min before turning on the pump (Apex)
- Turn the pump on 2x/day for 1min to circulate water. After 1min, the hot water has not reached the Ti coil yet. This prevents stagnant water when not used during the summer. I do not purge the system, but have fittings installed if necessary.
- Misc. overtemp/undertemp emails & text message alerts (Apex)
AlexG
Valuable Member
I agree the pex connections need to be outside of the sump and should not be directly over the sump either in the event that there is a leak. In my case I used the pex to run the return to the hot water heater so there is only ~50-60ft of pex in my sump which is plenty. I have an entire 120 gallon sump that houses the pex heat ex-changer so the compactness of the titanium heat ex-changer is a nice feature to save space. Here is my heating setup https://www.youtube.com/playlist?list=PLB7yLHQeKst9CLnTgkMZaMecB_w29WVnz
That is a good delta temp on the heat ex-changer. I know when I was setting up my radiant heater I was worried it might heat the tank too quickly. I liked your inclusion of the apex graph in the video. Below is the temp graph from my apex. I really think this is a better way to heat larger tanks without the need for electric heaters. Thanks for sharing this article.
Any photos to show of your sump set up and the PEX? I am trying to understand the heating of the sump area with this method and the amount of space it requires. A sump area usually for folks has limited space. Very interesting article and I am super intrigued.
Visually coil looks same as received. It was pressurize when I received it. I also pressurized to 100psi and let it sit overnight to verify all welds were okay. The risk is the swagelock tubing adaptors (tube --> NPT --> Pex) are directly over my sump. Any leaks and it drips into the sump. Thankfully, I have had no issues. After a few temp cycles, I snugged the fittings again just to make sure. I use the Pro Pex system, so no metal crimp rings and foolproof to install. The temp probes are also in the same compartment as the heat exchanger coil. The tank temperature probably trends much slower. Apex chart below.
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DBR_Reef
Active Member
so maybe not better, but definitely a good in sump alternative and definitely cheaperVisually coil looks same as received. It was pressurize when I received it. I also pressurized to 100psi and let it sit overnight to verify all welds were okay. The risk is the swagelock tubing adaptors (tube --> NPT --> Pex) are directly over my sump. Any leaks and it drips into the sump. Thankfully, I have had no issues. After a few temp cycles, I snugged the fittings again just to make sure. I use the Pro Pex system, so no metal crimp rings and foolproof to install. The temp probes are also in the same compartment as the heat exchanger coil. The tank temperature probably trends much slower. Apex chart below.
Visually coil looks same as received. It was pressurize when I received it. I also pressurized to 100psi and let it sit overnight to verify all welds were okay. The risk is the swagelock tubing adaptors (tube --> NPT --> Pex) are directly over my sump. Any leaks and it drips into the sump. Thankfully, I have had no issues. After a few temp cycles, I snugged the fittings again just to make sure. I use the Pro Pex system, so no metal crimp rings and foolproof to install. The temp probes are also in the same compartment as the heat exchanger coil. The tank temperature probably trends much slower. Apex chart below.
Would there be a way to build some type of drip tray below the fittings so in the unlikely event a leak does occur it would drip to that and away from the tank? Might make the system almost foolproof.
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