[an error occurred while processing this directive]
Posted by Ruth on August 07, 2006 at 14:32:48:
In Reply to: Re: New update and question on sub loop posted by HeatPro on August 07, 2006 at 12:13:37:
Thanks HeatPro. Looks like it is hard to install one bypass for two pumps. The problem is the thermostat that contrals the heating on and off. When the room temperature is high enough and the heating stops, the thermostat will close and block the water flow. The boiler zone and the radiation zone will become two isolated loops.
For the radiation zone loop, the external pump is still runing and pushing the water to move, but the water can not go back to the boiler because the thermostat is closed. In this case we need a bypass so that the water can keep moving.
For the boiler loop. When the room tempreture is high enough and the thermostat closes, the boiler also stops running, that sounds fine. But the boiler also supplys hot water. Sometimes calling for a little bit hot water can also start the boiler, in this case the internal pump starts runing and pushing water to move. We will need a bypass to allow water to flow. The bypass installed in the radiation zone can not help because the water can not pass the closed thermostat.
If both the internal and the external pump need a bypass. Maybe we need to install two (one for each of the pump)? Looks like the fatory instruction did not consider the effect of the thermostat, and it it didn't say whether the bypass should be at before or after the thermostat. I was hoping that the internal pump has already been taken care of by the boiler's own bypass. Shall we install two bypass now? Thanks a lot.