Potterton Perfoma 28 Boiler Pressure & Hot water Issues

[Chris_B]

Hi all, New to the Plumbing forum, this is my first post.

Potterton Perfoma 28 Boiler, 7 years old from new, in the last 6 months the boilers pressure has been at or below 0.5Bar, the hot water tap would go from scorching hot to tepid to luke warm in a space of a minute when run on full.

Tried topping up the boilers central heating system through the filling loop which was already attached? so i followed the procedure by switching the boiler off, and with the system at cold i opened the cold filling loop valve to 1Bar, bled the radiators, (the highest Rad had lots n lots of air trapped), then filled back upto 1Bar. Ran okay for a day, although i cant recall what the hot water tap was like at this stage.

inspected the boiler with the front cover off and found that the differential valve body was leaking where its connected to the 3-way diverter valve body.

Now, this isn't my boiler, but the company who is contracted to maintain and service this boiler for a family member has told a member of my family that they need a new boiler, just after they 'serviced' it. but all they did was scrape the limescale build up on the heat exchanger plate. A while after this another boiler engineer of a big firm (i wont name names), came round to my familys household to perform another 'service' but shortly after leaving they left my family without running hot water & central heating.

After i inspected the boiler to see why the pressure keeps dropping i narrowed it down to this. See attached Pictures

I notice that the green sludge build up is a form of bacteria, could be giardia? at worse case? so i can understand that this is a health risk.

I am quite temped to fix this issue myself, i have repaired quite a majority of things so I'm confident with spanners and that. but i have researched that i can buy a complete diverter valve diaphragm kit including all the rubber 'O' rings and green nylon washers for £30 (Baxi branded)

any tips much appreciated, thank you for reading

 

[TBServices]

That boiler hasn't been serviced in a million years, and you shouldn't have even taken the case off.

Best advice is get a GSR in to assess the problem and avoid using british gas/the big firms. Just because you think that's the problem doesn't mean it is. Leaking diverter won't cause no heat and HW on its own. The leak may be the result of other problems. The pressure should not be at 2.5 bar, too close to the limit.

This thread will no doubt be closed, we will not give advice on gas appliances, post up in the plumber wanted section, there maybe a local GSR who can help.

 

[Chris_B]

Ok, thank you for the Honest advice and pointing me in the right direction, no doubt i shouldn't have even taken the case off.

 

[Chris_B]

Just wanted to update this thread,

Hired a Gas Safe Registered engineer to inspect further into this problem:

Diverter valve parts replaced (diaphragm & Pins)
DHW Heat exchanger replaced
Pressure release valve replaced
2 new Rads replaced (20 years old at least!)
Leaking rad valves replaced with TRV (1 old valve was leaking causing pressure bleed off)
X400 sludge remover added
Expansion vessel re-pressurized

I have to admit, I re pressurized the expansion vessel, The problem we also had was a pump/ low pressure fault on the boiler, and we had to turn the boiler off, turn C.H./ DHW on then turn boiler on to 'fool' it to work and to fire up, but the other problem we are having is the pressure is on 2.7bar when C.H. is on.

the household has 11 Rads, 2 of which are new and 1 had been flushed.

 

[Billy Bob Bob]

Just wanted to update this thread,

Hired a Gas Safe Registered engineer to inspect further into this problem:

Diverter valve parts replaced (diaphragm & Pins)
DHW Heat exchanger replaced
Pressure release valve replaced
2 new Rads replaced (20 years old at least!)
Leaking rad valves replaced with TRV (1 old valve was leaking causing pressure bleed off)
X400 sludge remover added
Expansion vessel re-pressurized

I have to admit, I re pressurized the expansion vessel, The problem we also had was a pump/ low pressure fault on the boiler, and we had to turn the boiler off, turn C.H./ DHW on then turn boiler on to 'fool' it to work and to fire up, but the other problem we are having is the pressure is on 2.7bar when C.H. is on.

the household has 11 Rads, 2 of which are new and 1 had been flushed.

keep running this at 2.7 bar and you will destroy every bush and o ring in your performa,if your gsr cant resolve it,either find a competent one or get baxis people in,heat team

 

[Chris_B]

Hi, Thank you for your reply.

What would cause the boiler to operate at extremely high pressure? I have to constantly keep an eye on the pressure and turn it off before it gets too high. when I turn ALL the rads off, it operates and hangs around just under 2bar

Thank you

 

[Mike Jackson]

Normally knackered expansion vessel. They are quite often a right mare to change and if there is room look at fitting an external one.

 

[Chris_B]

Ok thank you,

My next question;

How do I size up a new expansion vessel for the house? Basically what size expansion vessel to get?

Thank you

 

[Masood]

Ok thank you,

My next question;

How do I size up a new expansion vessel for the house? Basically what size expansion vessel to get?

Thank you

Seriously, get a COMPETENT GSR engineer in. He/she will be able to calculate that accurately. As said above, get that wrong and you WILL need a new boiler. The work you've had done already doesn't seem untoward, but there does seem to be a quite obvious thing missed out. A decent GSR will know.

Try posting here: [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL] with your location and you'll not go wrong...

 

[Dotty]

Seriously, get a COMPETENT GSR engineer in. He/she will be able to calculate that accurately. As said above, get that wrong and you WILL need a new boiler. The work you've had done already doesn't seem untoward, but there does seem to be a quite obvious thing missed out. A decent GSR will know.

Try posting here: [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL] with your location and you'll not go wrong...

Good advice there. Thread closed.