Drop in hot water pressure - combi boiler

Hi, I hope someone here can help as I'm currently tearing my hair out!

I had to turn off the hot water supply to refit a hot tap in the bathroom as the plastic nut had broken. Stupidly, rather than just turn off the mains at the internal stop-cock, I first tried closing the valves under the boiler. This didn't work so I turned off the mains, changed the nut and opened all the valves and turned the cold water back on.

The problem I have now is that the hot water pressure is much lower than before. Never had any problems with this previously but now only one hot tap works at a time and even that is low pressure. I've tried everything I can think of including making sure everything is fully open but no joy.

Any advice would be very much appreciated, thanks in advance!

what boiler?

nickso said:

what boiler?

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Ah, that would help wouldn't it! Its a Jaguar 23kw combi boiler which is made by Saunier Duval

cold water flow is ok? just the hot taps affected?

nickso said:

cold water flow is ok? just the hot taps affected?

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Yep cold water is fine, just the hot taps.

hmm. could be a few things.

i can't remember what type of filter/restictor these use but thats a possible fault. perhaps something has happened to the isolation valve on the cold inlet to the boiler not allowing it to fully open.

you could prove its the boiler by removing the cold inlet from the boiler and checking the flow rate into a bucket, then doing the same to the hot oulet, a lot of faff but it will prove it.

if it is the boiler then im afraid its a case of removing bits until you find a blockage or fault.