Worcester 28si II

[dscanlan]

Hiya,

Our Worcester 28si has been installed for just over 4 years now and has never had any issues. Recently, I, noticed that the pressue in my boiler is running bewteen 3 and 3.5

I tried it with the central heating (CH) on and the pressue increase. switched it off and the gauge reduced slightly. Last night i noticed that i was getting closer to 4 so switched off the CH and again it reduced. This morning i noticed that the pressue has again increased.

I've been told that this is looking like the heat exchanger needs to be replaced. I've had a look around and found this post:

//www.diynot.com/forums/viewtopic.php?t=44212

What i am struggling to find is which heat exchanger i require. Would anyone be able to tell me if there is anything else that could have caused this and if that is likely to be the case tell me the heat exchanger that i require?

 

[Agile]

Look at the FAQs on this site with particular reference to the explansion vessel and if necessary repressurise that.

If this is not the cause the follow the FAQ advice for diagnosing a leaking secondary plate HE.

These have a habit of failing on Worcesters.

Tony

 

[bones001]

There is only one heat exchanger on your boiler. It has no plate to plate but a twin pipe running through the single heat ex. Yes they do split inside and cause the mains water to mix with the ch water causing the boiler to continuosly pressurize but you may want to check the filling loop has not been left open or is passing first of all. Also if it has increased overnight without the heating on it will have nothing to do with the expansion vessel. If it only increases when the heating is on take agiles advice on the expansion vessel

 

[Agile]

Oops, sorry, yes this is a four pipe HE.

If the expansion vessel checks out OK and there is still a problem then set system pressure to 1 bar at night and then close the mains water inlet valve and leave hot tap open.

In the morning if its still at 1 bar then repeat the next night and if it goes up then its the secondary circuit within the primary heat exchanger.

That can happen although its much rarer than the leaking plate HEs on worcesters.

Tony