Need som Hot water advice.

[thudpucker]

I have a shed I can work in.
It also has the Hot water heater, Washing machine and dryer and a Sink with Hot n cold water.
To keep Pipes from bursting in the winter, I'm going to route some hot water out of the 6 Gal heater, and circulate it through some piping around the other cold water pipes, and may even put some in the floor to keep this un insulated shed warmer than the outside temp.
See the drawing for the Question.




See "T-IN" where the recirculating hot or cool water re-enters the Tank.
At that point I think I need some kind of a Valve to prevent the incoming cold water pressure from fighting my Circulating pump.

Also, the Pump.
A 6 gal hot water heater might have a recovery of 1 hour. Meaning you wouldn't want to run the whole tank out in one hour.
So....we want a circulating water speed of 3 Gallons per hour (is my guess)

I think I can hook a spare Electric motor up to one of those Automotive store specials and make it run at 3 Gph.
I don't know how long those Rubber impellers would hold up running Hot water though.
Anybody have any experience there?
How about the cheapest Trash pump you might know of that will run hot water?

If I make this work, I may make a heated slab down in the Barn using a 6 Gal Electric H.W. heater and a pump on a Thermostat.

Somebody on this forum will know about that?
C'mon back and advise all of us. This info could be a boon to guys who like to work in the cold winter.

[TollyWally]

Radiant floor heat using water heated in a hot water heater works great. I'd use a bigger heater than 6 gallons. You can get purpose built circ pumps at moderate cost. Google pex tubing and see what comes up.

I've put infloor heat in several houses I've built in Alaska. Both the "right" way and the gyppo way. Both work prety well. For what it's worth it's pretty easy and cheap to insulate a shed. Everything you do will work much better. Usually down to 20-25 degrees a light bulb will keep the pipes warm enough.

[thudpucker]

I put Wersbo tubing in the one home I built in Chugiak AK.
It was great. I sold the home, the couple split, nobody paid the bills, the place froze up and broke, water soggied it to death.
A neighbor sent me photos of the place being ripped up and hauled off.
Sad...

But I loved it, my granddaughter crawled around in her diaper when it was Zero or colder. Great way to heat a place and pretty healthy too.
Sometimes she'd lay on the floor and put her little cheek down to catch the heat and sleep.

I only have a few pipes on the wall to heat.
I'll figure out how to circulate that water with some alternate pump method.
6 gals is enough for a slab 12X15 to make it comfortable to work in in the winter.
I'll cut and fit some blue board to seal off the area above the rafters, and the walls. I'll put the plumbing inside the Blue Board, and 25' of 3/4" PVC I'll have well protected pipes.
Its just a matter now of finding a real Cheap pump that I can operate with a Pipe Temp T-stat or even a Wall T-stat down where the Pipes start to freeze.

An aside: Somebody here just ordered fuel oil and put a note on the tank, "CLOSE VALVE FIRST PLEASE" the oil got delivered in the dark (It's January) and the deliverer didn't see it. The guy inside had been working on the furnace and soon smelled diesel in the carpet of his living room - talk about soggy! (they said 100 gallons but that seems a stretch)
I don't know how to best rig your circuit but I also vote for insulation - the water heater, itself, might be enuf to heat the space.

[duke]

Fine plan, you can get a little electric water heater and a Taco 120v pump and be in business, but don't mix your potable and your heat. Isolate the system with a double check-valve backflow prevention device.

There's laws that say you need to, for one, and meningitis for another.

-duke

[thudpucker]

Thanks Duke, somebody else mentioned Legionnaires disease from Algae building in the circuit.
I'm glad you guys mentioned the Potable/non-potable separation because I was going to use the potable water tank.

I'm now doodling on the newest deck down in the barn for inside work next winter.
Dick

[Submarine Tom]

A technician I used to work for used a 6 gallon hot water tank to run his open circuit warm water floor heating in a 20 X 24 foot, two story home here in south west Canada. He went as simply as possible except on the tubing in his concrete pad. He went with the good stuff and has had zero problems. He supplements it with a wood stove when it gets cold (below freezing) but he says it's the best thing he did in the home. He adds about 1/4 a cup of water a year to the open reservoir. He had to have base-board heaters to pass the inspection before they could move in but returned them after that for a full refund.

-Tom

[thudpucker]

In AK, my house was 26X60 and I used a 40 gal tank. I had to cut the heat all the way down to 40 degrees and add Celing fans.
Its the best and cheapest method of heating.

[CDK]

Your plan will work fine, but it'll keep working much longer if you use a small central heating circulation pump. The modern ones have 3 speeds and there are versions available for potable water.
I do not think you need any non-return valves if you use smaller tubes for the heating circuit.

A more secure system would have a heat exchanger so you can add anti freeze in the heating part!