Hot water in the house went off the other day, still had heating though. the gas/heating engineer advised it was the diverter valve, had it replaced today but it hasn't fixed the issue so we're needing to try the circuit board. What I'm wanting to know is whether anyone know a cheap place to get the part from.

 

Fi it's a potterton 30HE boiler.

 

Also, could I do the circuit board myself? Looks like it's pretty much plug and play

If its anything like my Worcester then it MIGHT be the water flow sensor. Its basically a little impeller that spins round with the flow of water when the hot top is open. It tells the boiler to light the burner basically. On mine the sensor had failed (jammed I think) and when going through the inbuilt diagnostics the water flow was "0".

 

I actually asked a heating "engineer", (there's more engineer in my Tshirt with a picture of an engine on it...) that came round who informed me that the gas supply pipe was suddenly the wrong size and that's why it had stopped working after 2 years but there we go... When he had changed the supply pipe (in his defense a job that I wanted doing as I wanted the pipe moving) and it still didn't work he proclaimed he wasn't much of a diagnostic man....

 

Anyway, long story short if you have a diagnostic manual and the boiler can give you sensor readings I would recommend looking carefully at it. The repair and replacement sensor on mine cost me about £17 and 10 minutes work, about 8 minutes of that was draining the water out of the hot water system!

Boiler PCBs aren't a cheap part, period. Unless you know for sure through process of elimination it's a lot of money to 'throw' at it, if it doesn't fix it you won't be able to return it for a refund!

 

I found the cheapest place for our PCB was off eBay, had a quick look and there's some listed for yours

British gas one price fix, google it

Your engineer doesn't know what he's doing then. You can manualy overide diverter malve and you'll know if it's foulty. Get a new engineer

Will have a look Al thanks.

 

Baz - that's what I'm thinking expensive mistake to make

 

Quavey - I'll try and look out the diagnostics

 

Rolandas - even after the parts come out, he still said its faulty and was stuck in one position

Edited February 17, 201510 yr by bird

If you do have heating then your boiler fires up. 99% it's not pcb. Check your setting maybe hot water is in off mode

Its definitely a combi boiler right?

 

Assuming so, it could be a number of things. In what manner do you mean the hot water went off? You simply have no hot water full stop, or it runs hot then cold? If you turn the heating completely off and turn a tap on does any thing at all happen or does the boiler appear lifeless?

 

Possibilities include:-

Hot water flow sensor.

Hot water temperature thermistor.

Heavily scaled plate heat exchanger - this would cause hot/cold/hot/cold behaviour.

Diverter valve body or motorised head (doubt its an old type diaphragm based valve).

It is unlikely to be the main PCB.

If you do have heating then your boiler fires up. 99% it's not pcb. Check your setting maybe hot water is in off mode

 

I don't have either now mate

Its definitely a combi boiler right?

 

Assuming so, it could be a number of things. In what manner do you mean the hot water went off? You simply have no hot water full stop, or it runs hot then cold? If you turn the heating completely off and turn a tap on does any thing at all happen or does the boiler appear lifeless?

 

Possibilities include:-

Hot water flow sensor.

Hot water temperature thermistor.

Heavily scaled plate heat exchanger - this would cause hot/cold/hot/cold behaviour.

Diverter valve body or motorised head (doubt its an old type diaphragm based valve).

It is unlikely to be the main PCB.

 

So originally, the hot water tap was knocking the boiler off but just running cold. Now it still just runs cold but I only get 2 lights on the boiler.

Flame failure and safety thermostat

So the engineer has ermmmm made it worse?

Appears that way. Neen thinks it's possible that the board could have got wet while the engineer was fixing a leaky pipe (the ones to turn up the pressure)

Ahh if its now dead then its a different kettle of fish. Even with a broken sensor I actually got mine to give me some warm water through the heat exchanger preheat function which keeps the heat exchanger hot for faster response of hot water at the expense of gas and noise. (Which again told me there was nothing actually wrong with the heating or control side of the boiler). But if it won't do much now best I can suggest is turn it all of and leave it for a while and then start her back up and see what happens.

 

 

If not its looking more serious!

 

http://www.keeptheheaton.com/acatalog/potterton_PCB_s.html

Sounds like you're struggling Lee.

 

I know a very good trustworthy gas safe plumber and let's face it they're worth their weight in gold, he worked tirelessly last summer with me finding a fault (unconnected to yours), charged very little and always advises buying the cheapest way, even looking on ebay together.

 

Some or most don't care about your pocket like you've experienced, say buy this new from here today and it's £130.00 fit it - no better, oh it might be this so you fork out again - this i hate with a passion.

 

Scrap metal places do have complete boilers and 90% of parts on them can be migrated, you may get lucky and find an identical one then you've everything to swap out at will.

Never really thought of trying any scrap metal places. I think I could fit the PCB myself. It's literally plug and play. Our lass has managed to find a board at about £30 so might be worth getting and trying.

Changed the PCB today and the heating is back.

 

Question on the hot water side of things if you don't mind....

 

When I turn the hot water on, the boiler pressure goes up and up and eventually the boiler goes off. Same errors as before. Any ideas?

At complete rest and cold, say first thing in a morning is the pressure reading at 1 bar or in the middle of the green bit ?

 

I try to keep mine there, just noticed my boiler and it's just warmed the rads for the second time today and the needle is at almost 2.5 bar, will start falling now as it cools, still short of the red area, are you saying your boiler goes well into the red zone and then safety shuts down, hence your hot warm water tap you had running will of course go cold ?

To cut to the chase Lee, it sounds to me like your expansion vessel needs some air, so pump it up !!

 

I expect you might only have half a bar of pressure, check your manual but you'll probably need to get it up to 0.9 bar.

 

Then check on your needle daily, bleeding a rad will reduce the pressure, filling loop will increase.

Edited February 21, 201510 yr by phutumsch
added the word daily

You really need to give British Gas a call and either take a boiler and controls contract or just pay for a one off repair.

All this guessing is getting you no where.

 

"When I turn the hot water on, the boiler pressure goes up and up and eventually the boiler goes off. Same errors as before. Any ideas?"

 

Very strange, generally system pressure and hot water function aren't really related on a combi boiler. The system pressure is the water in the primary side and radiator circuit.

It could be that when you run the hot water, the heat generated in the plate heat exchanger opens up a small leak inside this plate to plate and so main water pressure 'leaks' into the primary side of the plate and over pressurises the system. If that makes sense and trust me I know what I'm talking about!

 

Stop playing and call BG!

Edited February 21, 201510 yr by lonezedder

At complete rest and cold, say first thing in a morning is the pressure reading at 1 bar or in the middle of the green bit ?

 

I try to keep mine there, just noticed my boiler and it's just warmed the rads for the second time today and the needle is at almost 2.5 bar, will start falling now as it cools, still short of the red area, are you saying your boiler goes well into the red zone and then safety shuts down, hence your hot warm water tap you had running will of course go cold ?

 

I think your expansion vessel is ready for some air as well. When cold 1 bar of pressure is good, then when all rads hot, pressure with a very healthy EV shouldn't get anywhere near 2 bar unless you have lots of radiators.

 

As a healthy example I recharged one yesterday on an Isar HE30. Pumped vessel up to 1bar with system open (i.e. blow off valve open), then re-seated, refilled system to 1.5bar, got all rads red hot (10 of them) and system pressure only read 1 3/4bar. That's how it should be really.

Edited February 21, 201510 yr by lonezedder

I think your expansion vessel is ready for some air as well. When cold 1 bar of pressure is good, then when all rads hot, pressure with a very healthy EV shouldn't get anywhere near 2 bar unless you have lots of radiators.

 

As a healthy example I recharged one yesterday on an Isar HE30. Pumped vessel up to 1bar with system open (i.e. blow off valve open), then re-seated, refilled system to 1.5bar, got all rads red hot (10 of them) and system pressure only read 1 3/4bar. That's how it should be really.

 

I have 16 rads !!

 

So hence this is the reason my reading shows a bit more than the norm then ?

^^^ Obviously the more radiators, the more water to expand in the system. Different boilers have different sized expansion vessels though.

Personally though, based on your cold pressure of 1bar rising to 2.5bar when hot, I would say your EV is ready for some air. 16 radiators is plenty, but not uncommon these days.

And of course the higher your run the boiler stat, the more expansion you get as well.

The main job of an EV is to take up this expansion of water and keep the pressure in the system stable. If there is no EV then the water can't expand and so the pressure rises instead, a flat EV is essentially no EV, so the PRV will operate at 3bar as a precaution to stop seals failing.

^^^ Obviously the more radiators, the more water to expand in the system. Different boilers have different sized expansion vessels though.

Personally though, based on your cold pressure of 1bar rising to 2.5bar when hot, I would say your EV is ready for some air. 16 radiators is plenty, but not uncommon these days.

And of course the higher your run the boiler stat, the more expansion you get as well.

 

On further inspection it seems when cold my pressure was not 1bar as stated previously more like 1.35 so i've dropped it down, this therefore the reason when operating it was nearing the red area methinks.

 

What happens the filling loop does not fully close the valve iirc, so i shall disconnect it as i believe you should anyway and cap it off once i am 100% happy i have it settled at close to 1 bar in a day or so.

pay your gas bill:whistling:

Lee have you tried......

In the Right hand isolation valve under the boiler, (heating return)

you will see a nut facing forward, AFTER ISOLATING ELECTRIC & WATER

SUPPLIES, drain the boiler, remove the nut, there is a mesh filter (strainer) inside, my guess is it is filled with crud, wash it out, and replace , refill and put back into use, problem solved

 

"Taken from another forum"

 

also found this on Q&A site for your boiler ......

hi, i think this could be a faulty condensate trap or pcb fault, as i have something similar with one of my customers boilers. i found the condensate pipe was frozen, causing the trap to overflow and short the terminals at the top.if this isnt the fault with yours, then the next things will be the white sensor lead on top of the trap, or pcb fault.i would always reccomend getting a gas safe registered engineer in to work on your boiler, as he will have the know how and tools for the job, good luck and post back if this has helped, cheers

Edited February 21, 201510 yr by veilside01702