Thorn Apollo 50/65B Boiler

[Ian Denny]

I have a problem with a thorn 50/65B central heating boiler that is 20 years old. The problem is that when it starts up, it will run for 3 days or less and then cuts out. When it is re-started the main burner flame dies after about twenty seconds and it takes out the pilot light. It has always been looked after with regular servicing and regular top-ups of inhibiter in the radiators. Also, in the last few days it has had a new pilot light and a new thermal coupling fitted, but still the problem continues.

Can anyone help !

 

[gas4you]

Do you mean a new pilot injector?

My first thought would have been a partially blocked pilot injector, or pilot tube, RGI territory.

Have all the basics been checked with your gas supply and meter?

I would think the pilot is going out so stopping the main burner.

Has the gas valve been checked?

 

[twgas]

has the flue been checked, had loads of apollos, balanced flue and fanned, where inner flue rusts through and so recycles flue gasses causing pilot outage

 

[ChrisR]

When it is re-started the main burner flame dies after about twenty seconds and it takes out the pilot light.

Is it overheating when it does that? Dodgy overrun stat would cause that - pump wouldn't be running..

 

[phil.gas]

most apollos have a overheat stat with connecting wires into the t/c
wonder if that has been changed recently. and check the connections
onto the t/couple are tight.

 

[Ian Denny]

Spot on Mick at TWGAS, Checked the flue and it had rusted completed through. Many thanks for that.