Potterton 80 Combi boiler problem (s)

[thegimp]

Hi guys,

My first post is in regards the Potterton 80 Combi Boiler.

I've lived in my property for almost three years now and within the last year I've had some problems with the boiler.

Last weekend the boiler stopped working (on the possible coldest day of the year). I looked at the mains switch light and that was "orange". But the flame had gone out.

I called my father in law and he suggested I needed to release pressure to ensure the flame kicked in again.
On this I noticed the pressure gauge was almost 3 bar. The main panel states a safe point of 2.5 bar.

I called my father inlaw again and he suggested I went to a radiator and let some water out. Which I did and the pressure gauge dropped down to 1.9bar (or so).

The heating still wouldn't go on so I unplugged it from the mains and then took every plug off the circuit board. I then put the plugs back on the board and hey presto it worked.

But today I checked the pressure gauge as we needed the heating on as my son i ill. It was reading almost 3.4 bar. So again I let some water out of the the main radiator and the pressure dropped to just over 2 bar.

About an hour ago the heating came back on as it is on timed. I checked the pressure and it has gone back up again to over 3 bar. I can't keep taking water out the radiator everyday. I've switched it off for the time being but noticed when I was turning it off a noise from the pipes.

Can anyone suggest what I can do? I have no idea in regards plumbing what so ever.

Regards Steve aka The Gimp

 

[gas4you]

First of all check that the filling loop is fully turned off.

Remove the filling loop to confirm that it is not letting by.

There are only 2 ways that the pressure can keep rising after you have drained water off, 1, as stated above, 2, a pinhole in the hot water heat exchanger.

Also have a look in FAQ's about checking your Expansion Vessel, although from what you have posted I don't think it will be this this time, but still worth a quick check.

 

[ddk]

i was unaware these boilers had a high pressure cut off device. if the potterton 80 you describe is a Puma, then i would suggest looking at the metal backplate behind the PCB to check for signs of scorching which normally occurs in the top left hand corner, this would indicate a dry soldered joint on the rear of the PCB, which can be re-soldered for a cheap repair, but as with everything, better to have it replaced if that is indeed the problem

 

[baxpoti]

a pinhole in the hot water heat exchanger.

Very unlikely on this boiler

 

[baxpoti]

a pinhole in the hot water heat exchanger.

Very unlikely on this boiler

remove filling loop as per gas4you

 

[thegimp]

Thank you for taking the time to reply to my question folks.

I have no idea what a filling loop is? Where abouts is this item? Is it easy enough for a novice to look at?

DDK, I had a problem last year with the PCB which I had to repair and I am 99.9% sure it was the top left hand side of the PCB that had to be soldered.

Is it looking more like a Corgi registered repair man will need to come out?


Thanks again guys
Regards
Steve

 

[Kev F]

http://shop.ebay.co.uk/items/__fill...0feb9c5f6&keyword=filling+loop&agid=566802362

should be a silver braided hose with two shut off valves (usually black)

 

[thegimp]

Thanks eaton.

I've had to let some more water out this morning. I've switched it off again as it went up to 3.3/4bar.

I also turned the screw on the Filling loop anti clock wise. And even though there is lots of pressure there was no hissing what so ever?
I'm stumped on this as I would have thought the pressure build up would result in the hissing of pressure release?

I'm going to unscrew the PCB today and hopfully look at this filling loop.

Thanks again
Steve

 

[thegimp]

I use some solder on the PCB earlier.

Let more water out. Left it at 1.5bar.

Fired her up and all seemed well until about 50 minutes when the misses was in the shower. Heard the boiler banging (not loud but loud enough) so looked at the gauge. It was almost 4bar.

I switch off the water and drained the main radiator again and the pressure read approx 1.45bar.

I turned the water on again and the gauge read 2.3bar.

I really need to have the heating on during the night but doesn't look likely.

Anymore ideas?

Steve

 

[gas4you]

If the pressure is only rising when the ch is on then look in FAQ's on how to check the expansion vessel.

Try removing the filling loop completely after setting the system pressure to about 1 and a bit bar cold.

 

[ChrisR]

I also turned the screw on the Filling loop anti clock wise.

Filling loops don't have a screw to turn. They have a TAP at one or both ends. Often the plastic handle bit of the tap is bust so you have to remove it an use a small spanner.
Make sure you're turning the right thing. Not many have a nice knob like tis one:

 

[thegimp]

Hi guys,

Thanks again for the input. I tried the suggestion you suggest Chris R on the filling loop. There was still no compression however.

I called a Plumber out and he arrived yesterday. He had a look and said he thought the diaphram had gone. But he checked and all ok.

He pumped up the pressure in the expansion vessel (I think) and some other bits and bobs.

It work fine all night. However I have just had a knock on the door from a neighbour telling me hot water it dripping down the wall outside (upper floor maisonette). SO I checked the pressure and it has shot up again to 3.5bar.

Any other suggestions? I was told that I'd need a new boiler and gave me a price of £2,200?

Regards
Steve

 

[Aquaheat]

Release excess pressure from the boiler and then isolate the filling loop by physically removing the braided hose. Ensuring the tap is closed first of course.

If pressure still increases with this hose removed then leave hose off and isolate the main cold water supply to the boiler. This will result in a loss of hot water for a short period but will test the DHW heat exchanger. See if pressure builds with this isolated.

post results for any further help.

BTW, forgot to add the main cold to the boiler should be the centre pipe of the 5 that are entering the boiler at the bottom. (3rd from the left!!) Assuming this is a Puma 80.