Good evening everyone,

I'm having a strange problem with our Camray 5 Combi 70A oil boiler and was hoping to get a second opinion as to what the fault might be.

CH side of things is working A-OK - diverter valve actuator was replaced around 7 months ago (stopped working entirely) and is still working fine - pump runs without issue once the valve has 'turned' and activated the microswitch.

The problem is with the HW side of things - the pump specifically is causing trouble as it seems to pick and choose when it wants to work. For example; HW turned on at programmer; boiler fires, pump runs: heat store up to temp. no problem. Upon opening hot tap, 'flow' lamp is indicated on boiler (suggesting flow switch is functioning OK. However, the pump is not activating as it should when draw-off is detected, thus not circulating hot water from heat store through heat exchanger, so water at tap is ice cold (Scotland for you ) despite heat store being up to temp.

My initial thoughts are that a relay on the PCB is 'sticking', meaning that the pump is not getting a live supply when the flow switch is activated. I have attached a copy of the functional flow diagram which might be more obvious to someone other than me as to where the likely culprit is (I suspect it may be 1R3 which is 'sticking' and preventing the flow switch from activating the pump?),. A new PCB is around £125, so not a deal-breaker, however i'm wary of throwing money at it if I am missing a more obvious problem! I appreciate this is tiny compared to most problems with boilers, but times are tight so I am looking to be fairly sure before buying any parts.

As always thanks for any advice or suggestions you can give!

s2onius

Unfortunately this issue is continuing to confuse me; does anybody have any suggestions as to what might be the issue? It is definitely an intermittent fault, as sometimes thr pump comes on with HW draw and sometimes not, which would suggest to me perhaps 'sticky' relay that sometimes works? I would really appreciate a second opinion on the symptoms as I am off work in a week and would have time to replace pcb if that is necessary.

Thank you all for those who have read; hopefully someone will recognise the symptoms and be able to advise if I'm on the completely wrong track!

Pump needing rebuilt/replaced? Does it get hot when it actually runs?

Thank you for getting back to me; I really appreciate it.

The pump seems to be operating ok for the CH side of things (it runs without fail for that!) and only plays up in relation to HW draw. The pump does get warm on the bottom when running, however I always assumed this was due to the hot water running through rather than a fault(?).

As I say the CH problem is intermittent; sometimes the pump comes on and sometimes not: which makes it even more frustrating!

Just a quick update in case anybody has this problem in the future; a new pcb has solved the issue, so I have HW again!

Thanks again,
s2onius