HELP!! - Potterton 28i Combi - Hot Water Problem

[rossyl]

Hi

The problem is an intermittent hot water problem. Central heating is fine.

Sometimes we get hot water from all the taps and shower, sometimes we don't. Sometimes opening a tap fully for a few mins will result in hot water, sometimes it will just remain cold.

Basically sometimes it works and sometimes it doesn't.

The problem has been getting progressively worse. When the system was installed (4 years ago) everything was fine.

We've recently had the Secondary Heating Exchanger changed. This has not fixed the problem.

The next thing the Corgi registered boilerman has suggested is that it could be a problem with an electric hot water switch in the boiler.

My concern is I don't want to change the entire boiler part by part trying to find the problem, and end up chelling out a fortune. i was wondering if any of you have experince with this boiler and could suggest what the fault may be?

All help greatly appreciated - Thanks!!

 

[gas4you]

Anyone checked the diaphragm in the DHW differential assembly?

 

[rossyl]

I shall ask the plumber.

he came today and here's what happened....

He called the Potterton Engineers whilst working on the boiler and explained the problem of the heating not going beyond 30 instead of 60 degrees. They suggested that he changes the Sensor after going through various stages, as the Gas is not firing at full strength and it dips all of a sudden only when the Hot Water is turned on. He is going to change the Sensor this evening after getting the part.

 

[Agile]

He sounds like a parts changer without any diagnostic skills! To be avoided!

This is a simple and common boiler and he should not replace parts which are not necessary or need to call the manufacturers if he is competent which he clearly is not!

In my view you should not have paid for the new part if it did not fix the boiler!

Tony

 

[rossyl]

i agree.

after changing the Sensor as suggested by Poterton, the water is still only intermittant.

any ideas, or recommend me another plumber - North London/Potters Bar

 

[Vic Spanner]

Sounds like you have a sticky Pressure Differential Assembly ..Part 248728

 

[Minder]

I have exactly the same problem with a Worcester Bosch 28 Cdi. I get a poor supply of hor water particularly in the mornings when the heating is running. Problem has gotten worse since the clocks changed - I didn't change the clock on the boiler for a few days - seems if the heating only recently running, the hot water will not switch over when the demand comes on.

Is a pressure differential assembly part of the switching arrangement to move from heating to on demand hot water?