Potterton 28i Combi Diverter Issue?

[dave12]

Hi all,

Just looking for your opinion on this.

My Diverter Valve was recently leaking and as I have a cover policy I had Scottish Power out to look at it. They decided that they needed to change the valve as the couldn't get it open to chenge the stem.

Anyway, they guy came to change the valve and had a bit of a nightmare to be honest. So much so he blew the PCB by getting water on it then powering the boiler up! Doh!

So that was replaced along with the valve and the boiler put back in service. Which appeared to work fine.

However, I have now noticed that the downstairs radiators are cold, and the upstairs fine (Hot).

I have tried closing all the upstairs rads and the downstairs rads become hot. Having left the system like this for several hours, when opening all the rads up again, they return to how they were. (Hot Upstairs Cold down).

Could this be the Diverter valve not fuctioning correctly? What other things could I try?

For information, the Hot Water seems fine.

 

[dcawkwell]

No your system needs balancing.
Glad I don't have any cover with scottish. They sounds like a bunch
of numpties. It isn't hard to drain down a boiler and replace any part.
He should have also been equipped with a towel and a water vac!

It could be the diverter valve is still faulty and isn't opening fully to
central heating. But I'd try balancing the system up first if the downstairs radiators heat up quickly when you turn the upstairs radiators off.

 

[dave12]

Ha ha,

Well even I knew that, and I'm a spark! It was when he asked for the hair dryer after he had switched the boiler on I knew he had blew it (literally).

Anyway, so can a sparky (me) balance the heating? I thought my trick with closing the rads would do a similar thing but to no avail?
The downstairs rads do heat quickly once upstairs is closed.

Stupid question coming.....why would the system need rebalancing if nothing has changed with the rads/pipework etc? plus the valve is like for like/?

 

[dave12]

Hi,

I thought I'd post an update on this one as the Saga continues!

I am still with inter mittent heating and good old Scottish Power seem to be making a meal of this fault.

I had one of their guys around yesterday to (what I thought) fix the problem. However, he quickly installed a new Actuator for the Diverter Valve and packed up. He was quickly asked to check over all the heating and felt one radiator and diagnosed thatthe Boiler was fine and that there must be sludge in the rads.

So, from originally having a leak on the Diverter valve which as I understand it needed a replacement Stem (seal). I now have a new Diverter Valve (which is now leaking), New Actuator & New PCB. But the heating is not working correctly!!

Please give me your opinion. What do you think the problem could be Sludge or Diverter Valve?

If Sludge where did it come from when all heating was working before. (I have 8mm pipes by the way)

If the Valve, How can I prove this easily?

Many Thanks

 

[Agile]

Now you tell us you have 8 mm pipes!

Would you wire a ring main in 1 mm cable?

They seem to have made a mess of your boiler but if it worked OK before then I would expect it to work now!

You are lucky you have the cover!

Tony

 

[dave12]

Hi Tony,

Whats the problem with 8mm (microbore) pipes? I thought this was quite common?

I am going to check the plate heat exchanger for any heat when the heating is on. Obviously, there shouldn't be any heat it when the heating is on. But there is, surely this suggests the diverter valve isn't opening fully?

Thoughts?

 

[Agile]

8 mm pipes have a high flow resistance and block easily!

Tony

 

[Gasguru]

Anyone bothered to check the return filter?

 

[dave12]

Unbelievable!!!!

Just had the Scottish Power Guy (sorry can't call him an 'Engineer') round again to fit another Diverter Valve.

The Bad news is, the problem hasn't gone away! So could this be blocked pipes then? They were fine before the valve was originally replaced!!

Even worse now though, there is no Hot Water!!!

When running the Hot Tap, the boiler doesn't even acknowledge that the tap is running ie changeover to Hot water function.

I suspect he has not replaced a microswitch or something? But am not at the house to check... Where do SP get them?

Meant to ask, where would the return filter be? I didn't think there was one!

 

[Agile]

So how does the SP guy manage to leave the property with the boiler not working?

Tony

 

[dave12]

Tony, you wouldn't believe it!!!

Like I have said, I went from having a weep on the Diverter valve (So I was loosing pressure over the space of 3 - 4 hours). To now having 50% of my Rads operational and no hot water!

Since just before Christmas for this one fault (the weep) they have changed 2 x Diverter Valves 1 x Actuator and 1 x PCB And still the system is in a worse state than it was when I first called them!!!

They have just been to fix the Hot water and tried saying that my Wife had not switched the Boiler on properly via the selector switch! Although he acknowledged he also checked a plug. (I suspect from the actuator)

Needless to say, my confidence in SP is not great!!

 

[Agile]

Unfortunately, the only people who will work for those firms are newly qualified and the not very good ones!

An independent doing repairs has to be good otherwise he will stick to installing boilers.

Because I charge a fixed price wherever possible I need to complete a repair on the first and only visit otherwise it becomes uneconomic.

Tony