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Potterton Combi Boiler advice.....

Had a combi boiler fitted about 3 years ago. Had it serviced in the summer, shortly after we had the water fluctuating between cold and hot, plumber came back and fitted something, no idea what. For the last 4-5 months it has been fine.

Today the water is running cold, boiler sounds like it has fired up but temperature display climbes to 99, then `boiler light` goes off, temperature drops to about 81, boiler light comes back on and it climbs to 99 again, cycle just goes round and round, water stays cold.

Not tried heating.

Boiler is a promax HE.

Any advice/suggestions welcome.



  • Problems with my potterton have occured when the diaphram perished and had to be replaced, it senses when the hot water is on and swithes a micro switch to heat the water, this problem gives intermittent output. Another problem it had was when the exchager was blocked with rust flakes restricting the flow of water through it. Also when the water pressure in the heating system drops below 1 bar - just needs topping up by turning the tap on the boiler with the cold water feed to a couple of bars then turning off again.
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