potterton performa 28 boiler issues

[kapneil]

Hi i have a potterton performa 28 boiler which heats the radiators when ever the hot water is used??? Any idea why and what i can look for to resolve this issue. By the way last year the boiler repair man chaned the heat exchanger, but the problem remained.

 

[namsag]

Is it just a normal performa or the instant.

Normal one its the microswitch stuck on water section
instant it will be a passing divertor valve when on preheat

 

[kapneil]

thanks for your reply namsag.
I think it is a normal performa boiler. The micro switch(s) both work ok as i can see a pin from the valve make the microswitch. The microswitch nearest to the front makes when HW tap is opened and the microswitch furthest away from the front makes when central heating is required.

 

[Agile]

Namsag has not read and digested what you said.

Your problem is that the diverter valve manifold is not following the diaphragm section and is allowing some heat to leak to the rads.

Normally a new diverter valve. I have not found cleaning them to be very successful and always replace them.

Tony

 

[kapneil]

thanks Agile.
I will try and buy a new diverter valve and see if the problem is fixed.

 

[peterbaxi]

first of all if the heating is always on but room stat and clock are set to off then it is th hw microswitch stuck closed circuit, but if it comes on when you run a hot tap then it is the diverter valve letting by, also check plate heat exchanger is clean if not replace.

 

[adlplumbing]

pete i think agile has already told him the problem diavert vavle is passing

 

[Agile]

first of all if the heating is always on but room stat and clock are set to off then it is th hw microswitch stuck closed circuit, but if it comes on when you run a hot tap then it is the diverter valve letting by, also check plate heat exchanger is clean if not replace.

Peter, he has very clearly stated the problem is the rads heating up when DHW is used. Thats the diverter valve! The problem is made worse if the plate is seriously blocked due to the back pressure forcing more water round the rads but in that case he would also be complaining of hot/cold water.

He has not complained of CH coming on when not demanded.

Tony

 

[45yearsagasman]

At a risk of too many cooks etc,I have never changed the whole diverter.Why remove and scrap perfectly good parts when with a service kit and a clean you can save a whole heap of money.Just a thought.

 

[Agile]

For a rather mean friend during the summer, I took a diverter valve apart and boiled the components in citric acid to totally clean them.

I did not mind doing that because his very pretty wife kept me topped up with wine and it was hot and sunny so I could do it on the patio.

On reassembly I lubricated everything with silicone grease.

But a few weeks later it was leaking again. I think I know why! So I had to replace it anyway.

Tony