zachtos
Active member
I finally decided to implement my natural gas heater design. I would call the design a huge success. I'm estimating a 6-8 month payback based on my utility rates and kwh usage and $200-300/year savings.
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1418-1.jpg" border="0" height="600" width="800"></img>
parts laid out, note, I changed the original pump to a mag18
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1427.jpg" border="0" height="600" width="800"></img>
here is the 100' coil in the sump
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1457.jpg" border="0" height="600" width="800"></img>
proper fittings
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1435.jpg" border="0" height="600" width="800"></img>
pump connections, notice that it's plumbed so I can disconnect the pump, and still drain the water heater
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1434.jpg" border="0" height="800" width="600"></img>
Tee w/ valve off the hotwater line
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1432.jpg" border="0" height="800" width="600"></img>
Full Setup, I installed a new water heater to replace my 17 year old heater at the same time
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1065.jpg" border="0" height="600" width="800"></img>
my DIY ranco controller for $60
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1431.jpg" border="0" height="800" width="600"></img>
The Ranco controller turns the recirculating pump on and off
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/wheat.jpg" border="0" height="600" width="800"></img>
diagram to illustrate connections
Energy Calculations
I was using around 300kwh in the warm months, and up to 800kwh in the cold months. ($31-$88/month in electric heat). I should now use about 17 mcf to 45 mcf per month ($18-$48/month in gas heat and negligible electric use.) So, around $300/yr gas vs $550/yr electric (around $250 / year savings in energy, maybe more based on summer peak rates). SOOooo, the project does make sense for me, but you will have to run your own energy calculations. A kill-a-watt meter will help you determine if it's worth converting. But for reference, I would say a 1 year payback on a 500G system with electric rates of $0.11/kwh and $1.07/mcf. It cost $225 to build the setup I installed.
Results
-@$#$% Amazing. A water heater is around 40,000BTU, so when you convert that over, think of it as 30 of the strongest 350W heaters you can buy in your tank at once. It raised my tank from 55F to 80F in only 4 hours. 4 hours!!! My old 1200Watt setup would take a WEEK! I have the ranco set at 80F with a 2 degree differential. It kicks the mag on rougly every 2 hours for about 60 seconds. It takes... 60 seconds... to raise my 500G system, 2 degrees... this is because there is so much energy in the 100' PEX coil that it continues to heat the water after the pump shuts off. This is the perfect setup for doing water changes. It only takes about 15 minutes for the tank to heat from 74F to 80F after a large water change.
Caution
-use compression fitting for PEX
-use CPVC glue and couplings for CPVC and FLEXIBLE PVC
-your water heater may have lots of sediment in the bottom, it must be THOUROUGHLY cleaned before you start recirculating the water heater. Otherwise, your pump will clog up with sediment instantly.
-a mag drive is not able to withstand over 5psi, otherwise it leaks. I solved this with superglue, but that is NOT a solution, as I can no longer clean this $110 pump out ever again.
*using the wrong fittings for the PEX can result in a flooded basement or a dead reef system (thank me later)
Conclusions
This is a fantastic way to heat large bodies of water. It is cheaper, but not more efficient. The reason it is cheaper, is because gas right now is cheaper per BTU then electric. If you have a newer water heater or want to add a self cleaning feature to your water heater, this would be a great way for you larger systems to start saving cash.
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1418-1.jpg" border="0" height="600" width="800"></img>
parts laid out, note, I changed the original pump to a mag18
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1427.jpg" border="0" height="600" width="800"></img>
here is the 100' coil in the sump
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1457.jpg" border="0" height="600" width="800"></img>
proper fittings
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1435.jpg" border="0" height="600" width="800"></img>
pump connections, notice that it's plumbed so I can disconnect the pump, and still drain the water heater
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1434.jpg" border="0" height="800" width="600"></img>
Tee w/ valve off the hotwater line
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1432.jpg" border="0" height="800" width="600"></img>
Full Setup, I installed a new water heater to replace my 17 year old heater at the same time
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1065.jpg" border="0" height="600" width="800"></img>
my DIY ranco controller for $60
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/IMG_1431.jpg" border="0" height="800" width="600"></img>
The Ranco controller turns the recirculating pump on and off
<img src="http://i135.photobucket.com/albums/q151/zachtos/240G%20rebooted/wheat.jpg" border="0" height="600" width="800"></img>
diagram to illustrate connections
Energy Calculations
I was using around 300kwh in the warm months, and up to 800kwh in the cold months. ($31-$88/month in electric heat). I should now use about 17 mcf to 45 mcf per month ($18-$48/month in gas heat and negligible electric use.) So, around $300/yr gas vs $550/yr electric (around $250 / year savings in energy, maybe more based on summer peak rates). SOOooo, the project does make sense for me, but you will have to run your own energy calculations. A kill-a-watt meter will help you determine if it's worth converting. But for reference, I would say a 1 year payback on a 500G system with electric rates of $0.11/kwh and $1.07/mcf. It cost $225 to build the setup I installed.
Results
-@$#$% Amazing. A water heater is around 40,000BTU, so when you convert that over, think of it as 30 of the strongest 350W heaters you can buy in your tank at once. It raised my tank from 55F to 80F in only 4 hours. 4 hours!!! My old 1200Watt setup would take a WEEK! I have the ranco set at 80F with a 2 degree differential. It kicks the mag on rougly every 2 hours for about 60 seconds. It takes... 60 seconds... to raise my 500G system, 2 degrees... this is because there is so much energy in the 100' PEX coil that it continues to heat the water after the pump shuts off. This is the perfect setup for doing water changes. It only takes about 15 minutes for the tank to heat from 74F to 80F after a large water change.
Caution
-use compression fitting for PEX
-use CPVC glue and couplings for CPVC and FLEXIBLE PVC
-your water heater may have lots of sediment in the bottom, it must be THOUROUGHLY cleaned before you start recirculating the water heater. Otherwise, your pump will clog up with sediment instantly.
-a mag drive is not able to withstand over 5psi, otherwise it leaks. I solved this with superglue, but that is NOT a solution, as I can no longer clean this $110 pump out ever again.
*using the wrong fittings for the PEX can result in a flooded basement or a dead reef system (thank me later)
Conclusions
This is a fantastic way to heat large bodies of water. It is cheaper, but not more efficient. The reason it is cheaper, is because gas right now is cheaper per BTU then electric. If you have a newer water heater or want to add a self cleaning feature to your water heater, this would be a great way for you larger systems to start saving cash.