Ravenheat RSF 84et- Hot water not not enough!!!

[Agile]

Its difficult to see how a new diverter valve can fail to switch the CH.

I think this is a four pipe heat exchanger with a gianoni diverter which senses the hot water demand and circulates the system water round the HE during DHW demand.

The diverter valve pin should be checked to ensure its coming out fully on DHW demand.

Tony

 

[rizy102]

hi again,
didnt get a chance to swap/change the diverter valve. however, i checked again and the CH pipe is getting hot when tap is switched on. i also closed the CH pipe, so that no water would flow into that particular pipe and the water from the tap became very hot indeed.
does this confirm its the diverter?
also, the diverter valve pin does seem to be pushing out fully.
thanks

 

[richw]

If your CH is cold, and switching on a hot tap causes the CH to warm, then yes, your DV is passing. The boiler is trying to heat the HW and CH, which is doesn't have the capacity to achieve!

For what it's worth, I experienced this exact situation with mine. The diaphragm failed on the DV, so I swapped it for a completely new DV. As Sod's Law would have it, the new DV had a perfect diaphragm, but passed slightly to the CH. I got the same symptoms as you: water not as hot as it should be. After putting the working diaphragm into the old DV, it worked perfectly!

Moral of the story: do not consider a cheap 'lookalike' DV. By all means buy a cheapo diaphragm, but not the complete valve.

 

[rizy102]

right very sorry for the very late reply, but when i did manage to change the diaphragm i had hot water. at last
however, now i have another problem. when hw is switched on the boiler fires up no problem. after approx 30secs in turns off and water goes cold. after another 20secs the boiler switches itself on agin and water heats up. this cycle sometimes continues and sometimes the boiler stays alight for a long period(10 mins) when having bath/shower.
now what i noticed is that the auto air vent wasnt releasing any air when the system was refilled. so i bought a new one and brilliant, now all the air escapes through the auto valve. however, problem still is the same. when CH is on is does more or less the same thing. boiler lights up stays on approx 1minute then switches off. a lot of clicking noises from pcb (not Pilot light) and then boiler lights up again and stays on approx 1min. this cycle continues most of the time also.
i have a feeling it might be the heat exchanger, but a new one costs £240, so ill mostr probably just clean it out. anyone know what product to use for cleaning and how to clean them. also need to know how i can prevent limescale build up in the future?
thank you

 

[Slugbabydotcom]

CH thermistor
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