Rayburn 480k MX - Boiler will not ignite

[Gone-on-John]

My last post was not quite correct when I said that the purge fan had failed as well. when I tried it last night I did not have the boiler turned on at the thermostat control. It is in fact working. but no ignition. - John

 

[SJB060685]

I have asked on another forum with regards to this unit and had a couple of responses. Although the guy has explained to the best of his knowledge how the start sequence on these work and I understand what he said I could still do with a bit more further input (might not get it). I even contacted Rayburn technical to see if they could give me a detailed breakdown of the start sequence and despite my engineering background they wouldn’t release any detailed information. As with any pressure jet burner the principal is the same, just in this case more solenoids and a soft start function. Like I said before fan runs, ignition is on at same time, cell looks for strenuous light, if ok solenoids open and you should have ignition. Anything in this sequence could be the problem as could the boiler flue way as I’m told these can easily block on these units. I can’t really advise anymore because I’m not 100% sure at the moment on this model, all I will say is what Rayburn advised me was to contact them direct and get one of their registered technicians to rectify, obviously this will come at a cost though.

 

[MikeJhn]

That would mean the cell works in the opposite way to a normal burner, as far as I know the cell looks for the flame after ignition and shuts the solenoid if the flame is not present, perhaps the multiple solenoid's work differently on these units? At a guess I would say the solenoid is not opening during the ignition sequence or the feed line is blocked to that side.

 

[Gone-on-John]

I have attached the start up sequence from the servicing manual if it helps. The main clue for me is that the lockout light does not come on. Which seems most odd. I do have a multimeter and an oil pressure gauge but unfortunately I have very poor eyesight and find it hard to see where to stick them. - John

 

[Gone-on-John]

This is the schedule

 

[Gone-on-John]

Finally got hold of an engineer, who serviced the machine and replaced the air pressure switch. Still a few strange glitches but at least running now. Bill hurt but we are warm. Thanks for everyone's input. - John

 

[MikeJhn]

"Air pressure switch ?" just confirms I know nothing about these particular twin burner Rayburns, and at my age I am not going to try to find out either. LOL

 

[SJB060685]

Thanks John. I didn’t realise there was a pressure switch on these either. A course would obviously help me lol.

Thanks again

 

[SJB060685]

@Gone-on-John I’ve just noticed the start up sequence image you posted (didn’t see it at first). That’s very helpful, it tells me what’s happening and when. Where did you find this image? Could you provide a link so I can have a further study of rest of manual?

 

[Gone-on-John]

The diagrams are from the service manual that came with the appliance. I have scanned a few pages and attached them. It is a bit big to scan all of it, do you have any bits you would particularly like to see? I would have thought that there was a downloadable version on the Rayburn site. - John

 

[SJB060685]

Thanks very much John. These screen shots tell me virtually all I wanted to know. When you attached the burner sequence image yesterday I studied it and noticed that when boiler burner runs two motors are energised and only one when cooker burner is live. I assumed at the time the cooker motor is supplying cooker fan and pump and the boiler motor just a fan. Reading what you just attached confirms my thinking. One last thing I’m curious of and that you might be able to find is how the soft start pressure is governed. These pumps have a single regulating spool inside them, with the theory of say 10 bar setting at pump = 10 bar at nozzle but as you know the soft start on this unit is 6 bar so unless I’m being stupid there must be something else initially adjusting this pressure.
Thanks for taking the time so I can get a better understanding of these units, much appreciated and I’m glad you managed to find a decent engineer who fixed your problem.

 

[Gone-on-John]

Certainly when a pressure gauge is attached to the pump you can see the pressure change as the machine goes through its start up sequence. Sorry, I do not know enough to say what is controlling these changes. - John

 

[SJB060685]

Certainly when a pressure gauge is attached to the pump you can see the pressure change as the machine goes through its start up sequence. Sorry, I do not know enough to say what is controlling these changes. - John

Hi John. After posting this question yesterday I carried on thinking about it and I’m sure I’ve figured it. Thanks for posting your initial query and thanks for the information you’ve supplied, although this is just for these burners used and may differ from other twin pressure jets it’s taught me a lot about them, something I always wanted to achieve.

 

[Jon Sparks]

Hi, can you tell me the name of your engineer in West Somerset please