Potterton Performa 24 cycled now no dhw or ch

[szczajuszka]

Hi all

I have a Potterton Performa on which we turned on c/h about a week ago. Last couple of days the shower started cooling/warming subtley and yesterday quite definate cycle. Today the ch and dhw stopped completely.

If I reduce flow in c/h circuit by half closing one of the valves on the magnoclean filter I can get the boiler to cycle on for 18 seconds every three minutes to keep the radiators warmish (have an infant that needs being kept warm). Can't get any dhw though.

Have had the plate heat exhanger off this evening and cleaned as much as I could by flushing whilst tapping with a hammer - visibly improved flow.
However, still same.
What likely? Primary Heat exchanger?
Have tried to get someone to look at it over the weekend but no joy so looks like on my own. (unless anyone can recommned someone in St Albans who'll do weekend work?

regards

 

[twgas]

I would suspect your system is full of cr4p, you've "cleaned" the plate HE, played with the magnaclean (have you cleaned it). Try getting the system cleaned - either chemically or powerflush.

 

[bengasman]

Proper powerflush required here, I would say.

 

[szczajuszka]

Thanks for the advice, but will a chemical flush actually resolve the immediate problem or rather ensure it doesn't clog in future

 

[twgas]

cleaning is a long term solution - if it's done properly. the problem is, whether you have a chem clean or powerflush, if it's not done properly it won't be very successful over the long term.

 

[szczajuszka]

Thanks TWG, but what will get me up and running now? Happy to look pflush lterm but will it also sort out my immediate "dead boiler" problem

 

[twgas]

It might, with your description of fault it's not easy to say.
Ignore the heating for now, what happens, exactly (noises, movement of parts etc.), when you run a hot tap.

 

[Agile]

I dont think you can have made much effort to get anyone out to see it this weekend. St A is within reach of both North London and of Hertford.

Clearly your boiler needs some work both to get it going again and the clean the system. Power flushing would seem to be the solution but that may not be needed if the Magnaclean is fitted and working properly.

Was the magnaclean fitted recently just to try to solve this problem? Whose idea was it to fit it?

Tony

 

[szczajuszka]

TWGas

thanks for suggestions - here are results of testing.

dhw

In hot water mode only opn front selector switch.
Turn on hw tap, and pushrod on DHW Differential Valve extends fully and activates microswitch and pump turns on. No other sound or movement including ignition or attempts or any movement with Central Heating Pressure Differential Valve pushrod.
Turning off hw tap and all goes back to normal.


ch

If turn selector switch to dual dhw/ch then only thing happens is pump starts running (and will stay running if left here)
If I then slowly close the valve on heating return between magnaclean and boiler the pushrod on the Central Heating Pressure Differential Valve will move proportionally. There will come a point where the switch will activate and the burner will ignite. It will stay ignited for about 20sec and then stay off. If I were to turn on a hot tap during this time the psuh rod on the Central Heating Pressure Differential Valve would retract.

 

[Agile]

You have not answered my earlier question! Are my posts invisible?

Your boiler is sludged up and there is insufficient flow rate to operate the system flow switch.

Closing off the CH circuit causes flow through the internal bypass which increases the pressure on th system flow switch and causes it to operate.

Boiler needs to be investigated to clear the blockages. Probably need an experienced person as this can sometimes be difficult to achieve.

Tony

 

[szczajuszka]

Dear Agile (Tony),

many thanks for your comments. My efforts have been to contact the three corgi registered people who have worked on it this year (Feb, Mar and then April when the magnaclean was fitted). I have also asked the local plumbing shop to recommend people. None of these will work the weekend. Given that in the 22 months I have been in this house I have spent over £2000 with 3 corgi registered people to give me longterm problem free heating/hw without it seems much success you can perhaps understand that I am a bit hesitant about just pulling another corgi person from the yellow pages?

Are there any associations/websites where there are listed recommended tradesfolk, or would any of you put your reputations on the line in recommending someone who I can call who?

regards
Darren

 

[szczajuszka]

Dear Agile

Looks like my post to you went in at same time as you were typing yours. Please be patient as I am looking after a newborn as well. Having just read your latest post I can see how this makes sense. Looks like I will need to chance the yellow pages then.

Many thanks.

 

[Agile]

There are a few sites which pretend to offer trusted tradesmen but the reality is that they are subscription so anyone who pays gets on there.

That does not matter as much as the good guys dont need to pay for these advertising scams as they have enough work to do by personal recommendation and their own long term choice of advertising.

We have reduced out directory advertising as its not cost effective and only pay for the BT books now and a lineage advert in a Camden free paper. Normally I would have been able to sort you out today if you had asked. The last address I went to in St A was only 14 satnav minutes away but I already have enough jobs for today and we are going to a party in Ilford this evening.

I am amazed at the amount you say you have spent on your boiler. Hardly any of our repairs come to over £200 and thats only when there is an expensive part involved.

Tony

 

[bengasman]

If the problem is indeed caused by corrosion, a proper powerflush will sort the problem out there and then, unless parts have worn out due to debris floating around in the system.

The bad news is that there are just as many poor powerflushers as there are poor heating engineers.

It ususally pays to ask all local friends, colleagues, relatives and the neighbours until you find someone who has a chap that repaired their boiler more than once, and solved the problem accurately.
As Tony said, many of the best/better engineers don't advertise.

 

[szczajuszka]

Thanks all,

as it turned out I got 2 recommendations for the same chap from different people in our antinatal group - interestingly enough he doesn't need to advertise.

He came in on Sunday and agreed that Powerflush is needed, which he can do at the earliest on Tuesday. Have been quoted £400 for the Powerflush (we have small house = 6 radiators) - does that sound reasonable?

Thanks again for all your help.
Darren