Glow worm space saver MKII problem

[Applejack]

Hi
I have a glow worm space saver MKII boiler. It wasn't firing up and thought it was the main boiler thermostat & thermocouple, I purchased a new Ranco CL6P0102 boiler thermostat c/w thermocouple fitted it and the boiler fired up. This worked for a couple of days then the same thing happened again. If I turned the boiler thermostat to the off position, then turned it back until it was just on, it fired up, however, if I moved it to a higher temp it cut out. I refitted the old unit and all worked OK, I then refitted the new Ranco unit and this worked correctly. is there something else that can cause this type of fault?
Many thanks David

 

[townfanjon]

Oh eck , sorry david, one of the mods will be along shortly and explain

 

[Riley]

We will not give information relating to DIY gas work. It is illegal and against the rules of the forum

 

[Dotty]

Job 38.11