Potterton Combi 80 Hot Water Problem

[hoorgi]

I have one of the above central heating boilers. It has the problem that whenever you run the hot water, then turn the tap off, the pump stays on and after a few minutes the system makes an audible bang and gurgle and the 'Lockout' light switches on and it is necessary to press the reset button in order to get any hot water again.

This is a long running problem. I have been able to temporarily solve it by getting the air valve and flow switch changed. I then get about 1 year's use out of it, before the problem returns.

I would love to find a solution that will last, that is preferably not buying a new boiler. Any ideas?

It may or may not be relevant that the boiler is situated in a fairly small cupboard, but with vents at top and bottom (a reputable plumber installed this).

 

[Rob]

Lift off front cover. If the red LED is still on after the tap is off then it needs replacing im afraid.

 

[Agile]

Lift off front cover. If the red LED is still on after the tap is off then it needs replacing im afraid.

You really mean the red led needs replacing?

I would have expected the DHW flow switch!

Tony

 

[ChrisR]

[code:1]and flow switch changed. I then get about 1 year's use out of it, before the problem returns. [/code:1]
Well that is the fix, but 1 year is a bit short!
Are you in a hard waer area?
Did the guy really change the switch or just clean it? NB it has two parts, hydraulic and electrical.
Problem with H can leak, to make problem with E.

 

[hoorgi]

Thanks,

In London, I believe it is a hard water area. If I were to ask the bloke to replace the flow switch again, what should I tell him to do differently from last time, to make it last more than a year?

Does the air valve need changing too? (I have changed this every other time, along with the switch - am I wasting my money?)

Is there anything else I should ask him to do?

Paul

 

[ChrisR]

The problem is that the boiler keeps locking out and the answer appears to be replacing the flow swithc, but the real issue is why does it fail every year and do I need to ask my plumber to do anything different, when I get him to fix it this time?

Do I need to replace the boiler?

London isn't a problem, unless you're in a spot like Epsom where the water is very hard.
As I say, check what's actually being changed.

Air vent - only if it's leaking.

No, no need to change the boiler just for that but experience suggests you will periodically also have to change the pcb, pressure switch if the pressure falls, pump, fan, gas valve and diverter valve, in that order of frequency. And the HW flow switch and air vent