Ravenheat CSI 85T

[steve28]

Hi all,

Have a CSI85t thats developed a strange problem.

When the heating is OFF and set to SUMMER ie HW only, the boiler fires up fine when a tap is turned on and hot water is drawn, BUT the radiators get hot.

This happens whether or not the switch is set to HW only or CH and HW.

i've checked the thermistors by substitution and they are fine. When a tap is opened and the boiler fires, it runs on a while after the tap is closed again (few mins) heating the rads before switching off. The rads are getting excessively hot.

I'm thinking the PCB could be at fault because the CH runs even when its supposed to be isolated.

Anyone got any other ideas?

Thanks in advance for any suggestions.

 

[Deleted member 105431]

diverter valve faulty/jammed/letting by?

 

[twgas]

sounds more like a diverter problem than PCB to me.

 

[steve28]

Thanks guys -

Ill check that and see if the valve is jammed open/half open.

I assume its a mechanical valve and just needs unblocking but notice theres a diaphragm kit for it - so could that be perforated causing the problem?

Would you recommend replacing the whole thing or just attempting the diaphragm replacement first?

 

[Deleted member 105431]

Thanks guys -

Ill check that and see if the valve is jammed open/half open.

I assume its a mechanical valve and just needs unblocking but notice theres a diaphragm kit for it - so could that be perforated causing the problem?

Would you recommend replacing the whole thing or just attempting the diaphragm replacement first?

change the whole valve, guts are ruined.

 

[steve28]

Well,

after dismantling the valve I discovered there had been a leak from the top union - this had leaked into the microswitch and corroded it. NC/NO/C all open cct.

I took the valve apart and checked but the inside seals looked fine, so I have renewed all 5 washers, and will be fitting a new switch tomorrow.

Thanks for your help and advise.