Overheating Rayburn?

[Burnerman]

I've been sorting out this oil fired Rayburn today - it has a twin Nu-Way burner unit and provides DHW/heating and also has the usual oven facility.
The burners work fine (slow start type) and the oil pressure is fine at 145 psi as recommended. However, I'm not able to do a CO2 analysis as my Kane 250 is away getting mended.
After the unit has been running for a while and the house is really warm (22 deg) the overheat sensor trips on the heating side and shuts everything down. there is a reset button on the front panel and pushing this back in restores normal running.
Can anyone tell me please where the sensor is, and what it is governing? the Rayburn and flue are perfectly clean - in fact I had to take the flue down to clean it out.
Is it possible that I have too much air going into the burner, increasing the flue temperature this way, perhaps?
I'd be really grateful for any tips or suggestions.
Thanks and good evening, John

 

[Boilerman2]

Sounds like the Boiler Stat, I think it;s behind the Control panel
Your'e brave taking these horrendous cookers on, I did one a year ago, took 4 hours to do a straightforward service, now I try to avoid them like the plague!!

 

[Burnerman]

Thanks for the response, Boilerman2
This sure has been a learning curve, although I'm not guaranteed to die a rich man, trying to sort these things out.....
So far I've fitted new motor bearings - (which had a howl you could hear at 200 yards), the motor to pump drive had failed, the oil pump wouldn't pump more than 110 psi, the electrodes were sparking across the nozzle and there weren't any gaskets between the blast tube and the housing...other than an almost blocked flue due to a huge lump of fireclay cement being in there alls well...and the darn thing still cuts out courtesy of the overheat sensor. I guess I'll wait until my gas analyser returns - the house isn't occupied so no time worries there. Cheers John

 

[Burnerman]

Just an update for anyone who has to get involved with these monsters (Rayburn 499K) the thermostat phials, all 3 of them, are jammed into a tube just behind the control panel. Well scientific! Anyhow, replaced the boiler overheat one, and the thing stays lit.

 

[Boilerman2]

I'll bet you're glad that ones over....however if you thought the Rayburn was bad you should try a STANLEY 80 next or what about an ESSE Century? all PJ Cookers ar truly horrible

 

[Burnerman]

Fingers crossed, once I've put new oil lines on it and done a gas analysis that will be it for a while....however the CH circulating pump is starting to drone, and its buried somewhere beneath the chipboard floor - which in turn is covered with 12" square quarry tiles. I'll cross that bridge when I come to it! Cheers John

 

[rayburner]

Got a Rayburn 480 K here that's been in and working well a few years and apart from a couple of pump drives failing and the cooker stat it's been OK. The repair man I use is retiring soon and isn't keen on delving into it anymore but it has developed another problem with tripping out so I'll ask on here for some advice.
There are two trip out resets on this thing one on the control panel which is a little tiny pin and a large illuminated switch in the panel next to the floor.
The small pin trips on a regular basis maybe once every two weeks but the one near the floor has now tripped and will not reset this morning I've noticed some strange relay chattering noises recently.
Can anyone steer me in the right direction on this ?
Cheers
Ray

 

[Nige F]

Sorry old thread - I`ll get me coat and start another