Oil boiler problems

flopstocks

Hello in our property we have oil central heating and every so often the boiler fails to come in. If we go into the garage switch the power to the boiler off for a few seconds, then turn it on it works fine for a few days. Seems that resetting the electrics fixes the issue.

So far I have tried a different programmer, and this gave the same result. I am tempted to try another room stat (currently have a Honeywell CM907 fitted) but I don't think this would fix the issue. Any ideas as to what could be causing the problem?

Thanks for your time.

snowcat75

Is it locking out on the burner? or is the whole power supply going off.

flopstocks

No lockouts boiler just appears dead, simply turning off the power switch for a few seconds fixes the issue? There is power there before resetting as the programmer stays on.

mark-w20

What boiler is it

flopstocks

It is a Worcester Danesmoor 15/19

mark-w20

Is it just the power to the boiler you switch off or is it the fused spur for the complete heating system.

flopstocks

Just the switch feeding the boiler, the programmer gets it power from the same supply also. Just after switching the power on the circulation pump kicks in and the boiler fires up.

jayyar66

I'm going to make the assumption that your system is either a 'Y' plan system with a single, 3 port, motorised diverter valve or an 'S' plan with two 2 port motorised valves. Either way, the sequence of operation is pretty much the same. The programmer doesn't control the the boiler/pump directly. The programmer switches power to the respective valve/s, there's approximately a 10 - 15 sec delay as the valve motors open, power is then switched, via a micro-switch within the valve, directly to the boiler/pump. It could be that the valve/s are intermittent in operation and need repairing/replacing.
Equally, it could be a loose/intermittent connections somewhere.
Are the symptoms the same for both heating AND hot water?

Seronera

As above really. If you have a 3 port valve or 2 x 2 ports they will have a lever that enables you to set them to manual operation. If that triggers the boiler, there's your problem.

mark-w20

Seronera wrote: »

As above really. If you have a 3 port valve or 2 x 2 ports they will have a lever that enables you to set them to manual operation. If that triggers the boiler, there's your problem.

Just to add to this, be a little carefull with this method of diagnosis as not all valves will open far enough with the manual level to operate the micro switch, the manual lever is really only there to lock the valve open whilst filling and draining down, also if it's a 3 port the boiler will only get it's power supply via the valve when in the heating only position, whenever hot water is calling the boiler power comes via the cylinder stat.