Boiler Needs Manually Refilling With Water Frequently

[Dorsetfella]

Hi

I'm hoping some one can point me in the right direction as i have the following fault with my boiler.

My water pressure gauge drops to zero every couple of days and prevents the boiler from heating.
I refill from the stop tap,pressure rises to 1.5 and it's then fine for the next couple of days.

I have had two engineers out and they have checked the 'Pressure Release Valve' and said it's fine.
They have also checked the tube that connects to the valve and that exits the wall externally and this too is fine.
They said that because they couldn't find any leaks there was nothing further they could do.

There are no signs of any leaks anywhere in the house and so we dont understand why the pressure is dropping after so long.

It is a 'Ideal' Logic Combi and it is 2.5 years old and out of warranty.

Any help appreciated

Mark

 

[45yearsagasman]

If it's not going out the prv and there isn't a leak on the system then it may be the main heat exchanger leaking and going out the condensate drain. You won't see that unless someone goes looking for it. Did your engineer check the expansion vessel?

 

[Whitespirit66]

Does the condensate pipe (white plastic one) drip when the boiler is off?

 

[Dorsetfella]

The engineer checked the expansion vessel and said it was ok.
He mentioned about the condenser being tested and there was no leak there.
I remember he had an old fashioned hand pump which I guess he would have used for testing purposes.
Any more ideas? Thanks v much for your help soo far

 

[swbjackson]

Top up the system, turn the boiler off and isolate it from the heating pipes (two little valves under the boiler). If the pressure gauge drops the leak is on the boiler. If the pressure doesn't drop open the isolating valves. If the pressure now drops the leak is on the system. If the pressure still doesn't drop it is either the expansion vessel or the heat exchanger is leaking when hot.

 

[Dorsetfella]

**Resolved**

Good news,fault found,it was the heat exchanger,and it was replaced foc by manufacturer because boiler was under two years old.

Thanks to all who tried to help.

 

[Agile]

He mentioned about the condenser being tested and there was no leak there.

Not very clever then! Or perhaps lazy and tells lies?

Was he an independent or a substandard engineer working for some kind of boiler insurance cover firm?

Tony