Posted by Harold Kestenholz - Hydronic Network on March 07, 2001 at 10:13:54:
In Reply to: phase III hot water overheating posted by Dave on March 07, 2001 at 07:42:58:
If the water to the tank is prevented from reaching the tank by a closed zone valve, the water can not be heated. This means that the sensor that opens and closes the zone valve or the zone valve itself is awry, keeping the zone valve open. Undersized piping would prevent water from reaching the heat exchange coils in the phase 3 tank, making the water colder, not hotter. The cause needs to be solved.
The moaning noise can be caused by a blockage or steam being produced in the boiler. The boiler control should prevent converting water to steam. Get an experinced heating plumber to correct the problem.