Potterton boiler no C/H

[mais01]

I wonder if anyone can suggest what the problem might be here:

I have a wall mounted Potterton 16-22 boiler it has begun playing up.
We have a plentiful supply of hot water, boiler sparks up no problem but no central heating.
The PCB failed about 12 months ago and an makers relacement was fitted.
Had a gander under the cover of the boiler nothing obviously wrong can be found.

Any suggestions on this would be greatly appreciated.

 

[seco services]

checked the motorised valve next to the pump ?
is the pump running ?

 

[Aquaheat]

If boiler is firing for DHW then you can pretty much take the boiler out of the equation.

Check the following:

3 Port valve,
Pump, (both as previously suggested, thanks seco)
Room thermostat
Programmer

 

[mais01]

Thanks for the replies.

Exuce my total ignorance on this.
How do i locate the and second work out if it is working.

 

[Aquaheat]

How do i locate the and second work out if it is working.

Think we might be missing a word? Locate the...?

 

[mais01]

Apologies trying look at the various diagrams etc and write at the same time.

Totally dumb question i know.
How do i locate and test the pump.
Cheers

 

[mais01]

Having got over my blond moment.
The pump is a Grunfros selectric, i have removed the middle screw type affair and have a dribble of water out of it as per FAQ 9.

The "Mid Position Valve" which i am assuming is the three way valve was in the "H" position i did however notice that there appeared to be some form of switch/lever trip that was showing at the bottom of the unit.
When pressed back in the switch has moved to the M position.
After switching the mains to the boiler back on hey presto we suddenly have hot water and heating.

Thanks for the advice it is sincereley appreciated.

 

[GodKnows]

Depending on make of DV they sometimes stick or jam, you have positioned it to the mid position. This is used for flushing the system and would suggest you get an RGI to check that it just stuck or has failed. The Mid position is only to be used as a temporary measure fella...

 

[mais01]

Thanks for that.
Its an ACL LIFESTYLE midposition valve.
At the moment it looks as though the only position it will stay in is the middle one.
I guess the question now is what position shoudl it be in?
Cheers

 

[GodKnows]

It should be in either CH or DHW fella A or B...

 

[mais01]

Cheers for that looks like we have found the problem then.
It wont move to any ther position.