Zone valve / Hot rads issue

[Marty1966]

Hi, wondering if anyone can shed any light on the following;

I have recently replaced both zone valves (Honeywell V4043H) models as complete units hoping to eradicate the issue of the heating circuit warming up when the HW circuit is the only one selected. However the issue still persists. It seems to be the upstairs rads that get hot rather than the downstairs ones.
If I select auto/manual lever on one of the zone valves and push it across to 'open' the boiler fires up briefly, this does not occur on the other zone valve.
Anyone experienced the same issue and worked out the cause?
Wiring would seem an option but otherwise it all works with the programmer on both the CH and HW settings...
Thanks in advance
Marty

 

[ianmcd]

the return connection for your HW circuit has to be the last connection before the boiler, bet it is that

 

[Marty1966]

Ian, I'll have a look and see if I can decipher the pipework above the boiler- thank you

 

[ianmcd]

Ian, I'll have a look and see if I can decipher the pipework above the boiler- thank you

very common Marty and the upstairs rads will reverse circulate if not fitted properly

 

[Marty1966]

Ian, am i right in thinking that if the rads are heating up then the heating of the hot water in the cylinder is being compromised or does it continue to heat the water and the warming of the rads is an unwanted side effect - basically am I getting less hot water than I should ? Thanks

 

[ianmcd]

Ian, am i right in thinking that if the rads are heating up then the heating of the hot water in the cylinder is being compromised or does it continue to heat the water and the warming of the rads is an unwanted side effect - basically am I getting less hot water than I should ? Thanks

Yes it is a possibility, try closing a valve or TRV on one side of all the upstairs rads and see if your HW improves

 

[Marty1966]

Thanks again Ian, recently was informed that the pump had been plumbed in on the return circuit rather than the flow, after posting pics here for another issue so would that be exasperating the issue ?

 

[ianmcd]

Thanks again Ian, recently was informed that the pump had been plumbed in on the return circuit rather than the flow, after posting pics here for another issue so would that be exasperating the issue ?

Shouldnt be an issue really, it all depends on where the return from the HW cylinder is plumbed into the system

 

[Marty1966]

Having read a bit more Ive come across whats been described as 'Gravity Flow' which to stop this there is a check valve on the radiator loop - am I going off in the wrong direction with this line of thought.
I have some pics of the pipework immediately above the boiler which may make sense to you, would those be helpful ?