Protherm 80E combi F1 overheat error & leaking mystery

[greg123]

Hi folks,

Hope you can help me. I'm a mechanic, but no experience with combi's so need to pick your brains.

I have a Protherm 80E boiler, about 5 years old and still all shiny inside & clean burner so I'd like to fix it. It has had light use, single person before us (me + wife) in a 2 bed semi. It has two problems.

1) it's leaking from a black part which has a few wires coming out of it. It's dripping continually and I have to fill from the loop every couple of days or it gives me a F0 code with no water pressure. Also air builds up in the rads and if I push the pressure past 3.5 bar it makes a clanging noise and water tips out from the bottom of the boiler (relief valve?). I don't know if that's important, but I'm sure the leak from the black part is where the water is escaping - how air is getting in so regularly I don't know.

Two pics of the leaking black part which looks to be attached to another larger brass part - the black piece I'm talking about has a multi plug with wires coming out of it and a sticker with a part number. You can also just see the rust on the chassis indicating long term leaking which is getting worse:

http://www.ukdesigneritems.co.uk/greg/protherm/protherm2.jpg
http://www.ukdesigneritems.co.uk/greg/protherm/protherm3.jpg

2) it's giving a F1 code about twice a day now & cutting out (no hot water or CH) - this is urgent. I had the same problem and the manual says it's an overheat code. 6 months ago I replaced the overheat thermostat and the problem went away. Now it's back. I didn't replace the other overheat thermostat, or the hot water thermistor, not sure if I should just replace them all? Or if they are okay and something else is causing the thing to overheat? Once I press reset on the control panel it's okay for about a day at present, central heating seems to trouble it more than hot water.

View of front panel:
http://www.ukdesigneritems.co.uk/greg/protherm/protherm1.jpg

I have replaced overheat thermostat a) on this picture, but not overheat thermostat c) or hot water thermistor b)

http://www.ukdesigneritems.co.uk/greg/protherm/protherm4.jpg

Advice appreciated, please! Also if I need parts, a good UK online supplier would be great.

Thanks, Greg.

 

[kevplumb]

it looks like a motorised diverter valve

 

[Agile]

The black part is the flow switch and needs tobe replaced to stop it leaking.

F1 is usually an ignition fail code but if its a flow fault then the same part should sort that out unless there really is a flow problem.

Tony

 

[greg123]

Hi Tony,

Thanks for your reply so quickly.

I just had a look on the 'replacing parts' and on the wiring diagram and it seems to be listed as the 'pressure gauge' if I'm reading it right, is that the same thing as a flow switch?

The combi never has any trouble lighting up, first spark and it's off with a lovely flame - not sure if that helps diagnosis but I wasn't aware of any ignition problems.

If it's a flow switch/pressure gauge, any idea where I can get one from in the UK? Is it a common part or specific just to my boiler?

Greg.

The black part is the flow switch and needs tobe replaced to stop it leaking.

F1 is usually an ignition fail code but if its a flow fault then the same part should sort that out unless there really is a flow problem.

Tony

 

[kevplumb]

here

 

[Agile]

If the manual says its a pressure gauge then it probably is but not necessarily as some manuals call a flow switch a pressure gauge.

Regardless it needs changing! Then see if that still gives an error code.

Try Parts Centre.

Tony

 

[greg123]

Thanks Kev & Tony,

I have now contacted them both and hopefully will be able to get an answer/unit shortly.

don't suppose if either of you know if I need any o-rings/clips for fitting so I can order at the same time?

I can't take this one out to see till I get the new one as it's providing the hot water still! The manual is not exactly clear on the matter, saying something like 'replace the unit'....

Greg.

 

[Eeejit]

AS A TEMPORARY MEASURE - AFTER ALL- IT MAY ONLY NEED
A NEW O-RING, YOU COULD TRY SOME LSX JOINTING COMPOUND ON THE ORIGINAL O-RING.
YOU WILL NEED TO DRAIN THE BOILER, AFTER ISOLATING THE ELECTRICS, BY TURNING OFF THE HEATING FLOW AND RETURN VALVES.
THE DRAIN POINT IS IS JUST TO THE LEFT OF THE WATER PRESSURE SENSOR.

 

[greg123]

Thanks Eeejit,

I have found out that the part was superceeded which makes me suspect this one was troublesome, and luckily enough found a new one with clip and o-ring on ebay of the new style for £20 which is under half price of elsewhere. I'll do as you say with regard to locking off and draining and bear in mind the sealant if it looks like the new one isn't a perfectly snug fit.

I'm sure the new one will fix the leak, but if the F0 failures are still there I'll be back to pick more brains...

Cheers, Greg.

AS A TEMPORARY MEASURE - AFTER ALL- IT MAY ONLY NEED
A NEW O-RING, YOU COULD TRY SOME LSX JOINTING COMPOUND ON THE ORIGINAL O-RING.
YOU WILL NEED TO DRAIN THE BOILER, AFTER ISOLATING THE ELECTRICS, BY TURNING OFF THE HEATING FLOW AND RETURN VALVES.
THE DRAIN POINT IS IS JUST TO THE LEFT OF THE WATER PRESSURE SENSOR.