Potterton Suprima 40L not attempting to fire up...

Hi All

Firstly, a bit of history.

1) Boiler was brand new in a new build in july 2004.
2) PCB had lockout problems in november/december 2009 and i fitted a recon with higher grade components in december 2009 and have had just a handful of lockouts since.
3) On 04/12/14 i purchased another pcb and it hasnt fixed this problem.
4) Testing a brand new air pressure switch hasn't fixed the problem.

My boiler is not firing at all and is not even sparking or attempting to fire up.

When the boiler is called for heat, the fan comes on, i can hear a click from the microswitch opening (or closing) on the air pressure switch but no attempt at firing is made and after 60 seconds i get a lockout. It started with the extremely common lockout problems 2 weeks ago. Id come home from work, the fan would be running and the boiler wouldnt be lit. Id reset the boiler and it would then start up ok. This got worse and worse and since last sunday the boiler hasnt lit once. ive also noticed i used to be able to hear water flowing through the pipes of the boiler but now i cant hear anything but the fan running and the microswitch clicking.

i've had a plumber out who didn't know what the problem was and thought it maybe the actuator upstairs by the water tank as the lever on it seemed stuck but i've taken this off the valve it was on and am now manually adjusting the valve so water is flowing round.

As i cant hear water running through the boiler, i found a thread suggesting that there could be an air lock or a blockage and to take out the water pump and turn it around to reverse the flow then once it ran for a bit put it back to normal. When i did this, i could hear water happily flowing through the boiler but now i've put it back to normal i cant hear anything again.

When the boiler is called, and the fan starts, it is again intermittent that the pump starts running, i seem to have to take the power from the pump and put it back on at an angle to get the pump going but then it seems to be fine until i reset the boiler and the pump goes off again.

The boiler has a water flow switch fitted so i assume because i cant hear water flowing this may not be helping but even when i did hear water flowing before, it was still intermittent and would get the lock out problem.

About 1.1/2 weeks ago when it was intermittently working, i decided to tackle the problem of the largest radiator not getting very warm by locking down all the other radiators so the only place the water could flow was round the system and through that 1 radiator. This radiator then got hot (previously it had a domed cold patch from the bottom middle and only luke warm around that. I then adusted all the other rads so less flowed through them and more flowed through this one rad.

So far ive spent a long timing discussing this with one plumber and as mentioned above had another one come in to look and im getting no where.

And to top it its getting colder at the moment...

Desperate now and any help or questions for more info would be very appreciated.

Gaz

Don't take this the wrong way but you really need a gas safe engineer not a plumber and boilers shouldn't be worked on unless they are registered engineers and competent, I can't recommend anyone in your area but honestly an experienced breakdown engineer would diagnose this quickly, it is not a difficult fault to diagnose. Ask neighbours and friends for recommendations of engineers, there are good ones out there, just trust us!

A flow switch on a Suprima? Really ?

Not listed on the MI's that I just looked at to check to reassure myself (never seen one on a suprima yet...)

As per Forum Rules, (which I agree with) no Gas Safety Critcial advice will be given here by any Registered Gas Installer. As said get a recommended RGI to visit.

DH

Dread, you could get suprima with a built in flow switch, although they were a bit rare!
OP i think you system is pretty dirty, try a chemical clean and then, if it does need a flow switch get a RGI to sort as the flow switch is inside the boiler.

As said best get RGI to have a look , some suprimas do have a flow switch & pretty sure it works in series with the APS & throws up what looks like an APS fault.....
Not an area for tinkering with my friend

AFAIK, Suprima HE has flow sensor, not switch.

Standard Suprima has temp sensor, can't see any flow switch in all manuals.

The only boiler I think with flow switch is Potterton Promax HE

Daniel.

There is a flow switch in some of the standard efficiency suprima models it's not listed in the mi's but it is there, once you've seen one and had to repair you won't forget it in a hurry its that unusual! A gas safe engineer can work out how to repair easily

Hi All

Thanks for all your comments...

Regarding the flow switch, yes it does actually have one fitted (there is a sticker on the front of the boiler stating this too) but i dont seem to be able to upload a photo right now but it's installed on the front flow/return pipe and is an Altecnic 5109198 02. And double yes it isn't in the manuals ss that's already been pointed out to me.

I get everything you're saying guys but trust me im not touching anything that im not confident or competent at touching. Yes i changed the main pcb board but thats easy...i work in IT and am working inside computers all day so a pcb wiring is easy...and yes i took the pump off and turn it round and then refitted it the right way....again easy.

Also, the guy that came yesterday to look at the boiler was gas safe registered.

Everything ive done so far was to pre-empt a visit from someone else which looks like is imminent now then i suppose.

And I love your enthusiasm about an RGI gas safe engineer diagnosing the problem in 1/2 hr but from all my conversations with 2 of them and actually what i did miss off was a friend of a friend who fits boilers for a living who is also gas safe taking an hr to think it might be the Air Pressure Switch and then it not being, squashes that theory.

But i live in hope of not having a third week coming upto xmas without a boiler

When you replaced the pcb did you open the combustion chamber & replace the wiring loom aswell ?
If so what safety checks did you carry out to ensure the appliance was operating safely ?
" just curious "

Gasescape...thanks for contributing...in answer to your question no i didn't do anything like that...i spoke to several people and looked up a lot of info on the subject. there was no need to change to wiring loom as the board was like for like.

That's what they are saying, that's the problem. ( doing it yourself)

I've worked on a std efficiency Suprima with the flow switch, and it looks very similar to the one fitted to the Baxi Barcelona/Potty Promax. From memory (and it was 5 years ago) a loss of flow will give the same effect as an overheat i.e. immediate trip with user reset required.

It seems clear that the OP has sourced a recon or secondhand pcb to the original pattern if "he" hasn't replaced the wiring loom.

My suggestion to the OP is to remove and clean out the pump, which he appears competent to do, he may well find several impeller chambers are clagged up. If so it seems highly likely that cleaning it (or renewing it) will restore proper flow rates, get his system working again, and not cost him any extra money.


I echo the thoughts of others with regard to working on (starting with opening up the case - part of the flue system) gas appliances without demonstrating (in the legal definition) competence.

OP, if you've had the case open then get a registered gas fitter (Gas Safe) to check the safety of the boiler.

MeldrewsMate thanks for having confidence in me!

You are correct that i purchased a recon pcb but with higher grade components...i had to take the first one back that i purchased last thursday as it made the boiler worse...and the second one still wasnt enabling the boiler to ignite.

I asked the supplier to take the second pcb back for testing and they did and put it on test overnight, they said they had found a fault with it and the solder on the pcb that connects to the lugs on the air pressure switch socket had cracked and gave me another board. Im not convinced myself that something else wasnt wrong and they werent admitting to it.

Anyway, the replacement pcb worked and the boiler is now firing up ok.

Im unsure as to whether it was the pcb or the pump causing the problem but not operating and with no flow of water then the boiler wouldnt fire.

I was getting no voltage at all to the gas valve using a multimeter and now of course i am.

So, ive run the boiler all day and have bled what i can from the radiators and they are all hot except the one that i've always had a problem with and i think its blocked as there is a hot patch where the water enters and all across the top but its then luke warm down the right hand side to the opposite valve and then only luke warm at the valve.

This radiator is the largest at the lowest point and furthest from the boiler at the lowest point too and has always been problematic.

The water in the system is completely black so im thinking of draining it down, flushing it through and refilling again. I think the black is from the x200 (I think) that i put in months ago to sort kettling.

Now i'll get an RGI in to service the boiler although it probably doesnt need it now but i want the piece of paper to say its safe...

From the way you describe the radiator it would indicates the system is just not balanced...read the FAQ's and it should heat up.

In my experience it's extremely rare to come across genuine sludged up radiators...99% of the time it's just poor balancing or failed TRVs etc.