Does this sound like a duff programmer?

[RegB]

The oil boiler has suddenly stopped working, no lights, nothing. The programmer on the wall is a Drayton LP722, which is pretty old. Its digital display is active and the red lights are on, indicating that the water and heating are switched on. However, there's a cable (obviously) running from this programmer to the boiler. If I unplug the cable from the boiler and test it, there's no power, even though those programmer lights are on. Does this seem like a duff programmer box to you experts?

Any advice much appreciated.
Reg

 

[ianmcd]

Not necessarily, if you have an S plan or a Y plan system the programmer sends power to these controls and they send the power to bring the boiler on, could be a faulty programmer, you will need a multi meter to trace.

 

[Mike2007]

You might have a high level thermal trip if the control stat has packed in? There is a red reset button under the facial panel, try pressing it in.

 

[RegB]

Thanks Ian and Mike. I don't think it's an S or Y system. I know it's old, about 25 years. It's fairly basic with just two, 2-port motorised valves, one for the heating and one for the hot water. I removed the programmer box (after isolating it of course) and took it apart and there seems to be some scorching between two of the six terminals, and loose foil tracking on the circuit board, which obviously doesn't look ideal. Mike, there's a 'Limit reset' red button on the boiler but pushing it does nothing.

 

[Mike2007]

....

 

[Nozzle]

Also, what fuses do you have in the boiler. I agree with the remark ref S and Y plan.. These valve heads have micro switches in them, and if the switch has failed then boiler never gets the fire signal.

 

[RegB]

Thanks Nozzle. Can't find any fuses in the boiler itself. But following everyone's comments I've checked the motorised valves carefully and one of them is definitely shot. Looks like it's shorted due to a slow leak. The other one is fine. I guess that short could also explain the scorching in the programmer.

 

[undertrained]

Thanks Ian and Mike. I don't think it's an S or Y system. I know it's old, about 25 years. It's fairly basic with just two, 2-port motorised valves, one for the heating and one for the hot water. I removed the programmer box (after isolating it of course) and took it apart and there seems to be some scorching between two of the six terminals, and loose foil tracking on the circuit board, which obviously doesn't look ideal. Mike, there's a 'Limit reset' red button on the boiler but pushing it does nothing.

X2 motorised valves usually indicates S plan , if one is shot, then the other should work.

 

[RegB]

Thanks undertrained. I understand now. Must be S plan.

 

[oldbutnotdead]

That looks similar to my old programmer- that failed due to a similar issue with a 2 port valve. There's an internal fuse inside the thing but the PCB tracks blow much sooner. Repairable with a fine strand of copper wire soldered to bridge the blown track.

If the valve is a Honeywell you used to be able to buy the motor/switch bit separately from the valve head- much cheaper even then

 

[ollski]

If you don’t have a multimeter just link out the conections on the backplate to test it

 

[RegB]

Thanks OBND and Ollski. All very helpful. As it's an ancient programmer and was looking tatty anyway, I've decided to replace it with the modern version. Also got a new motorised valve with a replaceable head. I'll report back later if I can get it all to to work, but still worried about what other stuff might have been fried in that short.

 

[OvertonPlumber]

Those programmers suffer from stuck relays especially if one circuit left in the "on" position.
If you tap the programmer heavily above the big buttons it may go clonk and start working.
Oddley the newer ones suffer worse, cost cutting on parts after they were sold to Sneider electric.

 

[oilhead]

The switching capacity of the Lifestyle programmers is not suited to long life on an oil boiler. The start up current of the pump, burner motor and motorised valves can exceed the rated 3 amps. Many replacements are only 2 amps, so check before purchasing.

 

[RegB]

Good points. Thanks for those. Oilhead, is there one you would suggest instead?