What size reservoir for radiant heat?

belfert · July 18, 2009, 08:23:16 AM

I have a Proheat heater that will have three zones plus a zone for my water heater. What is the recommended amount of coolant in the system so I can size the the expansion tank or reservoir appropriately?

What are folks using for a reservoir if they need more coolant in the system? I know some folks have used a small electric water heater as a coolant reservoir which also allows for electric heating of the system if there is a seperate coolant pump.

JackConrad · July 18, 2009, 11:39:22 AM

Brian,
If I remember correctly, ProHeat recomends a minimum of 4 or 5 gallons (I don't remember which) of coolant to prevent short cycling, which afrter a few short cycles will cause the compter to shut down the unit. I found this out when my system only required about 2.5 gallon. I added the expansion tank shown for extra capacity.

belfert · July 18, 2009, 12:40:42 PM

Can you give me more specifics on that expansion tank? It looks like that would be good one to use.

JohnEd · July 18, 2009, 02:29:27 PM

Brian,

I think your "water heater for a res" was a HOT idea. Really, and pun intended.

Thank you for that.

John

Lin · July 18, 2009, 03:04:19 PM

I agree with John. It has started me thinking about putting a couple of fan/coils in a loop with my 10 gallon electric heater and adding a diesel boiler as an unplugged backup.

belfert · July 18, 2009, 03:16:02 PM

Quote from: JohnEd on July 18, 2009, 02:29:27 PM
I think your "water heater for a res" was a HOT idea. Really, and pun intended.

The water heater as a coolant reservoir is not my idea. I got the idea here or from BNO.

I was thinking more about it and I'm not sure it would work that well for heating the coolant. A typical water heater only heats to 130 to 140F. I suppose it would work, but have to run more to provide heat.

Lin · July 18, 2009, 04:28:12 PM

Well, the way I took it was the domestic hot water could be pumped through a loop that may have two fan/coil units. The 10 gallon water heater only puts out less than 10,000 BTU's, but that would work for many situations. Further, in a campground it would be relatively quite and be on free electricity. The diesel boiler could be used to increase the heat output or for when electricity was not available. Of course, you would need a different heat source for when using hot water for other things. I have not thought out any of the control details though, so it might not be workable.

gumpy · July 18, 2009, 06:08:36 PM

The water heater would not be used to generate heat. It would be used to store the hot coolant from the diesel heater. If you wrap the tank with copper tube, it can produce domestic hot water on demand, also, and when parked with shore power, it can be used to keep the coolant hot for domestic hot water, but the electric element is not intended to produce heating heat.

A friend of mine in Lino Lakes did this in his MC9, and it worked great. He passed away last year.

Lin · July 18, 2009, 07:12:45 PM

Well, I for one would not do it if it would kill me!