Ravenheat RSF 84 E - Won't fire up.

[MrStudley]

I have a Ravenheat RSF 84 E which I've had for about 6 years. Apart from a handful of new thermistors on the CH and DHW side and 1nr timeclock it has worked well.

It has now decided to pack in on me......If I either run a hot water tap or call for heating, there is a small click as the water moves through the system then the pump runs & the fan runs. But there is no attempt to spark up the pilot flame. It doesnt even make an attempt to 'click'.

I have changed the DHW & CH thermistors and have checked for continuity from the time clock.

Is it likely to be the air pressure switch? Or the ignition control box?

I read in another post that they originally had metal honeywell ones which are now changed to white HUBA ones. The fault finding chart is suggestting that the ignition electrode needs checking/is faulty. I put a meter through it and it made a circuit but thats about all I know to test it.

The guy I normally use for gas/boiler work is away at the moment. Although I'm sensible enough not to tamper with anything that would involve the gas side of this machine.

Please help...we need to bath the kids tonite. !

 

[Agile]

It sounds like a problem with the APS or the venturi ( or even the pcb ) .

However as this is a safety device it should only be worked on by somebody competent usually CORGI registered.

The metal cased Honeywell APS is highly reliable and uses an industry standard microswitch.. I only encounter about one every year which has failed in use.

The plastic cased ones are much cheaper for the manufacturer to buy and in my experience often fail. Even the ones fitted on more recent vaillants regularly fail a few months after the diverter valve has been changed.

Tony

 

[MrStudley]

Thanks

Are there a series of tests I can do to determine which is the faulty component?

 

[MrStudley]

A local engineer told me to whack the top, back, right hand corner of the boiler as it starts....

It worked an absolute treat !!

It shocked the APS back into the action. Getting a new one today.

 

[Agile]

A local engineer told me to whack the top, back, right hand corner of the boiler as it starts....

I dont see that as a very professional approach!

Gently tapping a suspected component with an insulated rod would be my method.

It sounds as if the contacts on the APS may have been oxidised. That could have been identified by measuring the "ON" resistance !

Tony

 

[MrStudley]

He used to do all Ravenheats callouts (they are just down the road).

He says the rubber inside the original APS's can harden up. He's recommended changing it for the white HUBA one.

The knock frees up the rubber component....apparently.