Potterton 100e continually firing but not lighting

9 Aug 2007
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United Kingdom
Hi! I have just moved into a new house which has a Potterton 100e installed I am told 4 years ago but not serviced.

The unit keeps firing up every 20 or so seconds and then shuts down - this goes on whenever the CH or HW are on - doesn't matter which.

We have plenty of hot water and the CH also works fine. But it just keeps firing all the time.

Any thoughts on solutions/cause?

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A huge boiler!

I would suspect its over sized if your heating and h/w is fine.

Plus a scaled heat ex.

Well it is a big house on three floors so I guess they thought they needed a big one!

I have also noticed that despite the heating being turned off most of the radiators are hot.
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dripping taps?

and diverter needs looking at.
I am guessing that this is the Puma in the contract version that is just called 80e or 100e. They ceased production about 1998 so if I am right there have been some porkies told.

It sounds as if there are more than one problem, with the diverter valve being one of them. Might just be the DHW flow switch though.

Is it a combi or do you have a hot water cylinder?


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