My 24cdi permenently increases CH pressure

[dom99]

Hi, I have just moved in to a house with a 24cdi combi boiler that is 4 years old. The problem i have is that the CH continually increases in pressure when there is no heating on. does anyone know what the problem might be?

In order to release this pressure to avoid any danger i have used the pressure release valve, unfortunately the valve has not closed and now i am losing pressure.

i know i am going to have to get some one in to maybe replace the relief valve but that will not take away the problem of the pressure increasing all the time once it is fixed, or will it!

We would be ever so grateful if can someone could offer some helpful advice.

 

[leafy]

Sounds like the plate heat exhanger is leaking mains pressure water into the heating circuit. With the type of filling loop fitted to this boiler thats the only place it could possibly happen.

 

[dom99]

Thanks leafy,

Is it possible to use a fernox product or another something else that can fix leaks for this type of problem, or help remove it from the equation, before i go down the expensive road of parts and labour?

 

[ChrisR]

'Fraid no elixir exists to mend that one. Rec retail is £131.29 inc vat for the heat exchanger, £13.41 for the prv.

 

[croydoncorgi]

Is the filling valve definitely SHUT and the large plastic 'key' REMOVED from the pipework under the boiler? The reason I ask is that although the secondary HX can fail it's unusual and there's only two places pressure can get from mains water to primary circuit of boiler.

 

[ChrisR]

I'm just replacing a plate h/e on a 24cdi - part arrived today!

 

[dom99]

I am sure the key is not in! unless there is a special way that you remove it so that it seals the mains from the enclosed system? i just trun it back and it slides out.

Im not sure i am up to fitting a heat exchanger and will probably look for someone qualified to fit it, if it is the problem.

Croydoncorgi, i may need you to recommend someone reliable who could have a look at my boiler as i am in the same borough.

 

[ChrisR]

"unless there is a special way "
There isn't!
Where are you - I'm west of CC.

 

[namsag]

Plate heat exchanger £84 inc vat . From www.onlineboilerspares.com . REF number 87161429020 . Or try gas appliance spares Preston whose prices are very rarely beat and have an excellent next day delivery service phone number 01772 702755

 

[croydoncorgi]

Devil finds mischief.....

Croydoncorgi, i may need you to recommend someone reliable who could have a look at my boiler as i am in the same borough.

Could possibly ..... this bloke lives in Croydon, CORGI registered, wastes a lot of time on DIYnot.... But with no email address contact is difficult!