Posted by Harold Kestenholz - Hydronic Network on March 29, 2001 at 09:54:24:
In Reply to: Hot water storage tank posted by Dinger on March 28, 2001 at 22:16:58:
I hope he intends to use a hot water tank with a heat exchanger to separate the boiler water from the domestic water. Most residential boilers will not take a relief valve over 30 psig by design.
It is the heat exchanger that will make the resistance to the flow of water to heat the tank. There are some tanks that have large diameter stainless steel coils
http://209.116.252.204/tw_space.htm
, a jacket that surrounds to tank, or many copper coils inside to permit gravity flow. These would be satisfactory for heating water by gravity.
Some are too restricted to use for gravity heating; so a circulator is required to drive the water through the 1/2-inch diameter or smaller exchanger bundle.