M
Mark_#9638
Hi, Hopefully someone can throw some light on if this is a real issue or not.
I have had this boiler for about 10 years, I noticed just recently that when the CH has been turned off that a couple of the rads closest to the boiler were slightly warm. When the boiler had demand to heat the DHW I felt all the flow and returns and discovered the CH flow pipe was hot.
From looking at the boiler the DHW and CH copper pipes inside the boiler are teed together so the 3-way valve had to be on the return, from what I can see there is a small stepper motor that actuates an arm which is moving the valve, however the valve itself is all part of the Grundfos pump housing and that looks like a right nightmare to replace.
What I would like to please know is:-
1. Is the hot CH flow pipe normal or not? I guess not as it's a waste of energy.
2. Is there any possibility the issue lies with the stepper motor or the base and actuator the stepper mounts too and not the actual valve in the pump housing?
3. Can the travel of the stepper motor be adjusted in firmware to move the valve more tightly closed or not?
4. If it is the valve in the pump housing is it a pig to replace and best to put up with the slight loss of performance until it gets bad?
I have not tested to see when there is only a demand for CH if the flow to the cylinder DHW gets hot but I am guessing if it does then whatever is deemed here will also cure that.
Thanks in advance
I have had this boiler for about 10 years, I noticed just recently that when the CH has been turned off that a couple of the rads closest to the boiler were slightly warm. When the boiler had demand to heat the DHW I felt all the flow and returns and discovered the CH flow pipe was hot.
From looking at the boiler the DHW and CH copper pipes inside the boiler are teed together so the 3-way valve had to be on the return, from what I can see there is a small stepper motor that actuates an arm which is moving the valve, however the valve itself is all part of the Grundfos pump housing and that looks like a right nightmare to replace.
What I would like to please know is:-
1. Is the hot CH flow pipe normal or not? I guess not as it's a waste of energy.
2. Is there any possibility the issue lies with the stepper motor or the base and actuator the stepper mounts too and not the actual valve in the pump housing?
3. Can the travel of the stepper motor be adjusted in firmware to move the valve more tightly closed or not?
4. If it is the valve in the pump housing is it a pig to replace and best to put up with the slight loss of performance until it gets bad?
I have not tested to see when there is only a demand for CH if the flow to the cylinder DHW gets hot but I am guessing if it does then whatever is deemed here will also cure that.
Thanks in advance
