Ravenheat RSF820/20T fails to heat water?

A common problem ( done mine 2x in 10 years ) is the diaphragm in the middle of the diverter valve that you have found central rear of boiler pipework . New full valve is approx 140 quid , new diaphram from suppliers ( you have to take valve to bits and replace diaphram ) is approx 40 quid , but my latest one was on e-bay and a fair bit cheeper . lots of pipework to remove first , new fibre washers needed ( cheap ) and not too difficult if you take it steady and you have some basic skills .Obviously check micro switch as well while its in bits , but they are pretty solid ...

rodney
February 2012

Right, having delved into the depths of the boiler case and enrolling the assistance of a glamorous assistant, I can confirm that the disc on the three way valve moves BUT that it does not contact the microswitches........

Over to you what know.......

Thanks again

John
January 2012

Just checked and we get around 6l per minute of water flow, so it suggests the microswitch may well be buggered.

SD mentioned these ought to be available on Ebay - can anyone point me in the right direction please?

Thanks again

John
January 2012

Wow, I didn't expect an answer that quick :)

I am guessing that ours may be older version than the one in your photo? Our heater has the clock, water and heating thermostats, etc on the bottom edge of the case.

Ours appears to have a 3 way valve / diverter near the centre, toward the back. This has as electrical box fixed on its far end. Do you think that could be the microswitch you mentioned? I need to hunt a mirror out to get a "proper" look at it.

I'll hunt out Ravenheats website later this afternoon.

Thanks again

John
January 2012

Water flow is detected within the boiler by a presure switch, remove front cover, about cntre behind control panel, a big valve unit, on end is a black covered unit, that is a microswitch, turn it slightly, so that you can see into it, get someone to turn tap on, you should see the disk in there move and operate the switch, if not, Either pressure to low, (water out should be same as water in, unless pipe work scaled up inside unit, probably difficult to descal, due to location. Cheap new one ebay) or the valve unit needs to be repaired, refurb kits on ebay about £11. if it moves, and presses on switch, poss switch faulty, standard microswitch available at electronic places. couple of quid. other than that, temp sensor, lft side, on the front pipe. Available new via ebay. You can get install manual with fault finding from Ravenheat website.

SD
January 2012