Glow Worm Easicom 28 Fault: CH Increasing Pressure

[cpcnw]

Hi All,

Wondered if anyone can comment on this to help me diagnose a little problem I have. The above boiler has been in place for a good 2-3 years (possibly longer) and has given pretty good service for both hot water and heating. The only thing I have done is clean out the Magnaclean a couple of times a year and on one occasion a few years ago, clean sludge that had built up around the back of the PRV (on that occasion I was getting slow drop in CH pressure)

Anyway this recent occurrence is one of over pressure up to about 2.8 - 3.0 bar

I have dropped the pressure back down to 1 bar, using a drain valve at the bottom of the rad near the back door, but the pressure rises again especially once the heating has kicked in. I have dropped the pressure a few times and the first few times it did stay low for a while however it is now increasing pretty rapidly.

From past experience I believe there are only a few reasons for an increase in pressure;

* Water is adding to the CH side because the valve(s) on either side of the filling loop are weeping

* The expansion chamber is leaking or needs re-pressurising

* The heat exchanger is leaking internally and passing water to the CH side

Is there a sure fire way to diagnose this? Heat exchangers for this model aren't too expensive but I believe its a beggar to fit. I could test the pressure on the expansion vessel or indeed add some pressure to see if that made any difference?

I do not suspect the filling loop valve but again that would be relatively low cost to swap out.

I guess I could just swap the filling loop / valve then test the expansion vessel pressure before doing anything else?

Any help appreciated...

Tia!

 

[terryplumb]

Process of elimination really. Do as you suggest ,disconnect f/ loop ( is it external to boiler )? And check the EV charge pressure ( you should drop system pressure first ). See what those establish.

 

[cpcnw]

OK will do - have to wait a few days as I am out at work. Will come back with my findings assuming I don't crack it - will reply either way.

Thanks for getting back to me.

 

[terryplumb]

Your welcome mate

 

[cpcnw]

One thing I forgot to mention in addition to the main symptom [ie incerase of pressure] is the following;

The mixer tap on the bath, for the shower, when showering the difference between very hot and tepid is now a matter of a few millimetres adjustment of the hot tap. So, start with the cold on full, then adding hot it is a right faff to get a nice hot shower without either scalding yourself or getting luke warm water. I am fairly sure that this was not the case some years ago?

This has started to make me think it is indeed the heat exchanger leaking... could still be wrong - and still not had time to check out the first two. Looks like it will be the weekend.