[an error occurred while processing this directive]
Posted by Susan on December 30, 2007 at 01:01:55:
Have a 6-zone under joist system using WM cast-iron gas boiler with indirect DHW and no outdoor reset. 6 zone valves are controlled and connected by 2 zone controllers and 6 room thermometers together. And there is only one pump in the whole system.
Both boiler and pump start and stop by demand from any of room thermometer. wonder what is the easier way to keep zone valve(s)open and pump running for let say 30 seconds or so after heat demand is satisfied so just to get the residual heat out of this cast-iron boiler. Water temp in the boiler gets and builds up as high as 25F past set high limit of 180F. any advise is greatly appreciated!