No DHW

[jcdel]

I have posted already on this subject but possibly I didn't explain fully.It is a Ravenheat 84ET and altho' I have fitted a new genuine Giannoni Diverter the problem remains.I can fire up on DHW but only if I tap the valve.This was also the case with the original valve.The sequence therfore is:-
Turn on DHW/Fan and pump operate but no ignition/Tap the valve 3 times and it fires up.Theoretically,the original valve was OK because we also had to tap that.At the moment due to kitchen fitment etc. we are using the boiler purely for DHW,(in effect as an instant hot water heater).Pressure is maintained at 1 bar but only one radiator connected.The boiler eventually is to be relocated in an upstairs utility room.The reason for posting mainly is that if we are looking at an expensive repair then sensibly we will just have a replacement boiler installed when we relocate it upstairs.

 

[Gasguru]

Is there more than one microswitch operated by the valve?

Perhaps the microswitch contacts have failed.

 

[Gas2Air]

If the spindle does move, does it go far enough to make the flow switch? Difficult to tell if the black cap is on the flow switch. As said it maybe a dodgy flowswitch, or i've had the water pressure switch have dirt in causing such a fault but rarely.

 

[jcdel]

Thanks guys,I'm on nights this week so not a lot of time.It is just a single switch on the shunt valve but I have just noticed that after I tap the valve,if I listen to the fan outside the house it does increase in speed and volume when it ignites.

 

[jcdel]

Another angle on the problem.I was putting the side covers back on and inadvertently (seriously) knocked the stepladders over and they hit the boiler(not hard enough to even dent the casing) and the bloody thing is working fine now.It seems that tapping the valve just vibrated something elswhere.Where the steps landed,is in the area of the fan etc.??????????
Thanks again Guys. (If it wasn't for this forum,I would be a single bloke).Now there's a thought!