Worcester Bosch HEATSLAVE 20/25 ignition failure

[CraigT]

Hi. I've got a Worcester Bosch Heatslave 20/25 oil fired boiler and the burner has stopped igniting.

I have done a fair amount of fault finding and this is what I have found:

If there is a demand from either the hot water, or the heating the burner blower starts, but there is no ignition. It also just continues to run like this; there's no lock-out.
There is oil getting to the pump, but no oil getting to the nozzle (checked by opening the oil pressure blank on the line from the pump).
When there is a demand for the boiler to ignite the oil pump solenoid is only receiving 131v, which I assume is not enough for it to open. The resistance of the solenoid coil is 2300 ohms. If I temporarily wire a fused 240v input to the solenoid terminals it operates correctly and the boiler ignites & runs fine.
Is this pointing to a faulty control box, or is there something else in the electrical circuit that might be preventing the solenoid from being actuated?

I believe that the part number for the control box is 87161200970. A search for this shows a new one to be about £200, however a search for a TF832.3 control box (as printed on the front) has led me to this (sorry, won't let me post url's): heatingsparescentre dot co dot uk/satronic-c23/satronic-control-boxes-and-accessories-c2970/satronic-honeywell-tf8323-oil-burner-control-box-p22492 , which is only £41. Is there a difference, or is this just a brand name thing?!

Thanks,
Craig

 

[kimbo]

If the motor runs and doesnt lockout it sounds like the photocell is checking for light. Disconnect the photocell leads and run the burner, if it fires and then goes to lockout it will be the photocell, if not it is probably the control box.

 

[CraigT]

If the motor runs and doesnt lockout it sounds like the photocell is checking for light. Disconnect the photocell leads and run the burner, if it fires and then goes to lockout it will be the photocell, if not it is probably the control box.

Hi Kimbo,
Many thanks for that. I disconnected the photocell & the symptoms are the same. I also spoke to Technical Support at W-Bosch & they agreed with the Control Box diagnosis. I've ordered one as per my link in the previous post & I'll let you know how I get on!

 

[CraigT]

Brilliant! The replacement control box turned up this afternoon. It's marked Honeywell rather than Bentone, but is still a "TF 832.3" and was £49.68 (including next day delivery). Two minutes later & it was fitted & the boiler's running fine again :smile5:.
Thanks again for your advice kimbo.
Craig

 

[Dotty]

Thanks for coming back to us Craig and glad you're back up and running.

 

[kimbo]

Well done craig

 

[SimonG]

Well fixed Craig, just glad I don't pay that much for my control boxes.