hot water recirculation?

pianotuna wrote:
Hi Gordon,

Any chance of a link to the pump? Thanks in advance.

GordonThree wrote:
The pump was advertised as a circulation pump for small-scale solar hot water, picked it up cheap from Jeff's website (amazon).

Looks like they've gone up, got mine for $15

http://www.amazon.com/gp/product/B00PXXJEHE

Huh, just saw this one listed as related... max temp 60C... magnetic drive HRMMMM

http://www.amazon.com/ZKSJ-Brushless-Centrifugal-Submersible-DC40E-1250/dp/B00C6XNB50

Hi Gordon,

Any chance of a link to the pump? Thanks in advance.

GordonThree wrote:
The pump was advertised as a circulation pump for small-scale solar hot water, picked it up cheap from Jeff's website (amazon).

tmartin000 wrote:
I'd pay a guy $50 to send me all the parts as a diy kit for my Lance camper. I hate these projects when you live 2 hours from home depo. :C

The local mom 'n pop hardware store actually carries the shark-bite fittings - if you have an Ace or Do-It-Best hardware in town you'll probably be in luck. If you have access to your hot and cold pex like I did in the picture, you need two T fittings, a 90 elbow and two 1/2" tubing to 1/2" FPT adapters (these screw onto the pump).

The pump was advertised as a circulation pump for small-scale solar hot water, picked it up cheap from Jeff's website (amazon).

I'd pay a guy $50 to send me all the parts as a diy kit for my Lance camper. I hate these projects when you live 2 hours from home depo. :C

Finally got around to installing my hot water recirculation pump. It works very quickly, keeping all of my water lines nice and warm - no freeze danger here until I run out of propane!



The pump is simply plumbed between HOT and COLD under my kitchen sink. Intake is connected to the hot, outlet to the cold, water runs in a loop using existing plumbing through the hot water heater.

At 12v the pump is turning too fast in my opinion, it puts out more pressure than my supply pump, so it feeds hot water to the cold water faucets. This is a cheapo impeller pump, I know it's not going to last forever. An purpose made induction pump would be sweet, but boy they're expensive. I have some induction pumps from my fishkeeping days (power heads)... hmmmm maybe something can be done after my road trip.

I have created a simple controller that will regulate the pump based on the temperature of the cold water line. When the cold water line drops below 45F, the pump will start... when the line rises over 50F the pump will stop. The controller will also e-mail me if it can't raise the temperature of the water line.

I'd like to put a pressure switch inline, so when a faucet is opened, the pump will shut off.

Could do it like this. Could just install the pump and have it operated by a thermostat (aquastat). A hot water recirc. loop in a house would be done like this except the pump would either run continuous or be on a 24 hr timer. The recirc line would be connected to the farthest faucet away. The pump would have to be rated for hot water use. Insulating the piping wherever you can get to it would help a lot.

There's a couple of types of pipe insulation that would work. A lightweight foam type like in 2nd pic available all over the place. Comes cut lengthwise with an adhesive strip. The other is a higher density rubber like type (EPDM) that is larger in dia. and has higher R-value - 3rd pic. Is not cut lengthwise and will probably have to go to a commercial insulation supplier. You might be able to push either one along the pipe where you don't have access but it could get hung up on something.

Hi Gordon,

I'd go with smk's recirculating method.

Dutch,

Do you know how I could access those water lines, without removing my black tank and the solvent-welded plumbing connections? I 100% agree heat tape would be the best solution.



The cold line from the fresh tank I can access, just need to build up the nerve to cut into my underbelly fabric and put heat tape on it.

The exterior water lines that are above the frost line at our cottage are protected by thermostat regulated internal heat trace wires. There are several brands on the market, including some that operate on 12 volts. Custom lengths are available from some manufacturers.

GordonThree - I will use one of these AQUA-HOT Model 200 i think it is for the main heat exchanger. This will fit in the same spot as the Propane Furnace if I get enough nerve to remove it... The Porpane heater is way too hot for my small foot print POPUP trailer floor plan and also the associated 12VDC blower is way to loud. I always tell everyone the blower sounds just like the GRRRR noise of sitting in the rear seats of the MD80 airplane. I wake up everytime it turns ON at night...

This is the AQUA-HOT heat exchanger with two axial 12VDC fans on the back of it. I used something similar to this back in my JEEP days to heat up the rear seat area... The 200 model has larger axial fans on it.


You can add additional heat zones to this idea and route the hot water around through some of these wall mounted heat exchangers. These don't have fans in them however. I guess you would need a a 12VDC pump in each zone and a different thermostat controlling the pump.


One of the guys from up north got some floor panels that had water lines built into them. Maybe they had electric wires in the them I forget. He put these in his bath room floors.

I noticed we have had these conversations before with much of the same crowd in those discussions...

I haven't done my mods yet either haha... If it was sustained colder here I would have it installed for sure. We get by just fine camping off the power grid using a couple of those 12VDC lap heated blankets. Then just put the loud furnace on a real low temp setting just in case it gets real cold and get under the covers. The 12VDC lap heating pads do great under the top bed cover at night also. My battery alarm will wake me up to turn off the heating pads when they drop down to 11.9VDC. I like to shut everything down when the batteries get down to the 50% charge state and then will re-charge them back the morning when I am allowed to run my 2KW generator during breakfast.

Roy Ken