Potterton 100 intermitent working.

[strugling_through]

We have a Potterton 100 combi boiler, running 4 radiators upstairs, and 2 double 4 foot radiators downstairs. It was installed 3 years ago, and this is the first problem with it.
For the last month, maybe once or twice a week, it can take up to 2 hours, sometimes longer, to fire up on the central heating. The hot water works perfectly, every time it is used.
I have found, that if I disconect the electricity, run the hot water till it runs cold, leave the boiler till it cools down, then re-start, it sometimes comes on, but not always.

 

[baxpoti]

The hot water works perfectly, every time it is used.

Sounds like the diverter valve is being held in hot water mode.

Try...... turning off the cold water supply to the boiler, check hot taps for any water dripping, or replace the diverter

 

[strugling_through]

If the cold water presure is to high, can that affect the diverter valve?

The reason I ask, recently, maybe 6 week ago. we changed clothes washer, and turned the cold suply off to fit. When installed I recall I put the cold suply on fully, where before it was only turned on less than half way.

 

[Agile]

Exactly which model is this?

If its really only three years old then I cannot guess!

 

[ChrisR]

Puma innit, installed 3 years ago maybe!

 

[strugling_through]

It is a Potterton 100 boiler. Yes it was fitted 3 years ago,the gc number is 47. 393. 04.....
I have turned off the cold water tap, it makes no diference, there are no leaking hot water taps. Do I have to change the diverter valve, as they are expensive, if it isn't the fault?

 

[baxpoti]

Do I have to change the diverter valve, as they are expensive

You don't have to do anything

If you want a second opinion call a local corgi engineer, or the appliance manufacturers Heateam

 

[Vic Spanner]

Do I have to change the diverter valve, as they are expensive

You only need to change the wax capsule that powers the valve open to the heating circuit .
Do you have to bleed your radiators quite a bit..I.E is your system dirty

 

[strugling_through]

It is loosing water presure, and I have to fill, through the fill loop, maybe twice a week. There are definately, no leaks. from the radiators, or the external pipe work. could this be my problem ?

I am sorry, buit I do not understand the inner workings of a combi boiler.

 

[baxpoti]

have to fill, through the fill loop, maybe twice a week. There are definately, no leaks.

If you keep putting water in, it has to be coming out somewhere

 

[strugling_through]

Can it not be leaking inside the boiler... Or transfering to the hot water suply ???
Sorry if this sounds stupid

 

[strugling_through]

May I firstly say thank you, for your help. I have changed the Wax Diverter Valve, and all is fine, although it took a long time to crack up afterwards. As the lockout switch, would not stay in, and fire up, but as I say, it is working fine now.
One question though:- When cold, the guage on the boiler, is showing 1 bar. when up to working temp, it is showing 2.5 bar. Is that normal?

 

[baxpoti]

You need your expansion vessel re-charged or replaced, or fit another expansion vessel to the system. This probably explains your leak!

 

[strugling_through]

Is the gap between 1 and 2.5 bar, to great ?

 

[baxpoti]

It's on the design limit!

The expansion vessel should be charged with 1bar air.

How many radiators are you running?