Ravenheat combi boiler (air pressure problem?)

MGAstra

Hi all,

I have recently installed a Ravenheat combi boiler LS-100T (yes those cheap and cheerfull ones from B&Q) but it has a problem trying to stay lit. I have done several of these boilers in the past and had no problems what so ever, but this one just wont play ball!

When either CH or DHW is called for, the ignition sparks and the burner lites. Then after a few seconds when the spark stops, the burner goes out. Then there is about 10 seconds delay before it tries again. This repeats three times then the flame failure light comes on.

This problem occurs with both CH and DHW, so i dont think it will be the overheat stat coming in.

I was thinking it may be the air pressure sensor if the flue has slipped out of position?

Has anyone experienced anything like this before?

Any help would be much appreciated.

Thanks!

Moss5

This may not apply, but my boiler requires live and neutral polarity to be correct. If reversed, it will allow a 6-second attempt at firing.
A neon screwdriver will confirm polarity is correct.
P.S You can link-out the air pressure switch to prove if that is the cause of the fault.

moneysavingplumber

Have you checked to make sure the pump has not seized and that both flow and return inlet valves are open and the main heat exchanger has been bled via the cap usually on top of the boiler?

I know the fault Moss5 has referred to is one that applies to the Baxi 105 regarding polarity, not sure about the Ravenheats though.

catkins

Is it a condensing boiler? My OH had a problem with one of them and it was down to the sensor on the chamber where the water collects to discharge.

MGAstra

Thanks for all your replies.

The polarity of the mains was incorrect!