Vaillant vuw 202/3-5

Peter_1974 · Post by **Peter_1974** » Tue Nov 12, 2024 6:32 pm

Hi Guys,

I have a problem with my heating, I hope one of you will know the reason.

Everything is fine, it makes heat and hot water. But the pressure keeps rising. 0,1 bar in two or three hours. I have already replaced the filling valve but nothing has changed.
I have no clue what to check or change...

All ideas are very welcome!
Thanks in advance,
Peter

dewaltdisney · Post by **dewaltdisney** » Tue Nov 12, 2024 6:54 pm

The taps on Vaillant if plastic can allow the fill to contine as the tap handle turns but the shaft does not.Mine has the Vaillant metal ones. Take the taps off and turn the square valve shaft with a spanner as a first move

DWD

Peter_1974 · Post by **Peter_1974** » Tue Nov 12, 2024 7:02 pm

Thanks dewaltdisney,

it's plastic, and broken.... So I use a screwdriver :)
Anyway, thanks for the idea!

dewaltdisney · Post by **dewaltdisney** » Tue Nov 12, 2024 7:53 pm

I am not an expert but rising pressure would suggest that the filling loop is open and your are probably discharging through the pressure release valve to keep it reasonably pressurised. All I can suggest is rechecking both the incoming and the fill valves again but I think you may be looking at getting Vaillant or a gas engineer in to sort it.

DWD

Peter_1974 · Post by **Peter_1974** » Tue Nov 12, 2024 8:11 pm

I think the same. The water goes into the heating circuit somewhere, so I replaced the filling valve. (I don't know if there is another place where the water can get in... )

dewaltdisney · Post by **dewaltdisney** » Tue Nov 12, 2024 8:49 pm

Let us know how it turns out, it may help others

DWD

Peter_1974 · Post by **Peter_1974** » Thu Nov 14, 2024 8:56 am

It seems, it is the plate heat exchanger. Not very cheap

dewaltdisney · Post by **dewaltdisney** » Thu Nov 14, 2024 9:28 am

Thinking about it, that seems logical. Sometimes, they can flush them out, but most fitters prefer to put a new one in. How old is the boiler?

DWD

Peter_1974 · Post by **Peter_1974** » Thu Nov 14, 2024 9:38 am

15 years, or something like that. Can't remember

dewaltdisney · Post by **dewaltdisney** » Thu Nov 14, 2024 9:51 am

Get a repair estimate because at 15 years, it is near the end of the boiler's serviceable life, and the repair may only delay the inevitable. At least the repair money can go into the replacement. Get a loan and do it over 5 years, as the new Vaillant boilers have a five-year warranty. Around £75 a month I reckon but saving through better efficiency and no need for a maintenance plan other than a yearly service. Check out British Gas as they have low finance deals on when I last looked.

DWD