Oil boiler fault

[pottsiwebber]

My burner whistled / squealed for a while before stopping. It turned out to be the old drive shaft coupling which was slowly eating the "keys" on the plastic part of the coupling allowing it to slip over the metal part attached to the drive end which was causing the squealing sound until it stopped driving the pump all together.

[Cliff top]

Sassen fassen rassen grrrrr

still cycling.

Getting closer though... May be the controller faulty....I can see the controller bimetallic going across and back as it cycles.
I am now working on the assumption that the flame detection cct is meant to hold the bimetallic at a certain temp stopping it going back to oil solenoid cutoff. New sensor and connection cable checked means it can only be the controller at fault.

Will rig up some wiring at work today to check it out.

[Cliff top]

To follow up on this for future reference:

Controller was at fault.  Replacement was actually worse! Still awaiting another to try again.

Anyway after running through how the TF830 actually works, established the cause of the problem is the C shaped spring on the 3rd (oil solenoid) contact. It requires enough spring power to flick the contact closed against the magnetism of the photosensor relay coil/plates which hold it closed until the flame goes out. Due to age the spring was a bit weak. Opened the C out a little and bingo it works...well most of the time. The whole thing is just a bit clockwork really.