Combi boiler on the fritz...and DH has chased out the repairman! Help!

[InWithTheOutlaws]

Our combi boiler starts flashing the water light after a few minutes of hot water and if you're in the shower it means you're suddenly showering in freezing water . If you switch it on and off again it starts up but only for a few minutes before flashing starts it all off again.

Called a repairman (I was out so DH dealt with) who said the (PCB?) board needed replacing at £200/300, DH said fine if that's what it is....chap came back today, DH got sceptical when he rummaged around, flipped some switches and then installed the new board.....there was a bit of back and forth I take it as DH questioned him about it and apparently he got angry and said to DH that well a simple diagnostic isn't worth his while so board it is! (The board didn't actually fix anything says DH). Repairman 'stormed out' says DH after the exchange.

Anyway....I understand it all garbled, I'm sorry - but does anyone know what the fault could be and how to find a repairman who's not charging for the sake of it but actually for the work needing doing?

DH is probably another problem that needs resolving , but boiler first!

Baxi combi or potterton performa by any chance?

Umm....just a regular British Gas one I think?

British Gas don't make boilers. What make and model is it? Should be on the boiler somewhere, usually on the front. Find the instructions for it online and look for troubleshooting and error codes.

British gas don't manufacture boiler but about gen years ago they went through a phase of branding boilers made by 3rd party companies as "British gas boilers" I can give you advice but I'll need as much detail as possible.

The only thing I can find written on it is C1. Will take a photo.

No it's fine, the c1 was based on a Worcester 28si

How many times a second does the hot water light flash per second? (Between 1 and 4)

Manual for your boiler here.

Looking at the troubleshooting guide which starts on page 32, and from the symptoms you describe it suggests:

"The gas valve mode switch (concealed by the facia side panel) is not set correctly." -> "Turn to NORM position"

Every second when it starts off Spangle.
Thank you for the manual, Cheese! We're off to investigate!

Does the boiler ignite and provide any heat or hot water before the fault? Does the fault occur with no heat or hot water demand or only when the boiler is in use. Has the nature of the fault indication changed in anyway since the last guy was there?

Aaaand it's working fine again.

Things that changed:

• switch was flipped by the repairman without comment who then insisted it was a new circuitboard that was needed and he put that in at the same time. DH thought it was just the switch flipping that seemed appropriate and the circuitboard was just random and asked him to put the old one back and see if it still worked (hence making clear it was just the switch) - which is apparently when he got huffy (and presumably switched it back.

• so switch was turned

• DH has increased the water pressure

• and cut around some hedging that had overgrown near the intake outside

Many, many thanks for all your help, really hope that's it resolved then.

PS: Just to answer your questions Spangle if it helps anyone - the boiler does start off fine, hot water starts up and then after a couple of minute started flashing and stopped heating the water. After that every time we'd try switching it on and off again it would heat water for 1-2 mins before flashing and cold water coming again.

Was it the gas valve mode switch (concealed by the facia {sic} side panel)"?

Do I get a cookie?

Not sure Cheese, tbh DH (feeling ridiculously vindicated, almost to a chest thumping extent) did it. But you certainly get the cookie and my thanks!