Hello,
First post
I have Y plan system for CH and HW via 3 port valve, Honeywell 4073, pump on its input side.
The CH works whilst HW is on at programmer (Potterton EP2000), but CH does display or work when HW is off at programmer, even if room stat is calling for more heat.
It has been the same since I moved in 4 years ago and previously assumed that was the way it had been set up, but time now to resolve .
In checking for a fault I note if I turn manually HW to OFF on programmer (via slider switch), the CH on the electronic display also goes off, even though slider is set for "24 hours" which seems odd.
I have read that a faulty 3 port valve (micro switch) can mean the CH does not run independantly, so the 3 port valve is perhaps to be suspected.
Q1) Would a 3 port valve (switch) probelm also explain the programmer not allowing CH to be displayed ON, on it's own?
If 3 port valve is faulty, my laymans expectation is that programmer will still display CH, as that is what it is supposed to be trying to set itelf to.
Many web articles talk of the no CH without HW problem, not don't mention whether this prevents programmer from displaying what it is TRYING to achieve.. even if microswitch faulty.
The genuine Honeywell replacement head is expensive, so would like to check the theory first.
Q2) Is there any other reason why the programmer would turn off the CH on its display when it turns HW off?
I have checked it is in the 16 programme position for pumped systems and that the HW off wire is present at the programmer.
TIA
David
First post
I have Y plan system for CH and HW via 3 port valve, Honeywell 4073, pump on its input side.
The CH works whilst HW is on at programmer (Potterton EP2000), but CH does display or work when HW is off at programmer, even if room stat is calling for more heat.
It has been the same since I moved in 4 years ago and previously assumed that was the way it had been set up, but time now to resolve .
In checking for a fault I note if I turn manually HW to OFF on programmer (via slider switch), the CH on the electronic display also goes off, even though slider is set for "24 hours" which seems odd.
I have read that a faulty 3 port valve (micro switch) can mean the CH does not run independantly, so the 3 port valve is perhaps to be suspected.
Q1) Would a 3 port valve (switch) probelm also explain the programmer not allowing CH to be displayed ON, on it's own?
If 3 port valve is faulty, my laymans expectation is that programmer will still display CH, as that is what it is supposed to be trying to set itelf to.
Many web articles talk of the no CH without HW problem, not don't mention whether this prevents programmer from displaying what it is TRYING to achieve.. even if microswitch faulty.
The genuine Honeywell replacement head is expensive, so would like to check the theory first.
Q2) Is there any other reason why the programmer would turn off the CH on its display when it turns HW off?
I have checked it is in the 16 programme position for pumped systems and that the HW off wire is present at the programmer.
TIA
David