worcester 24CDI RSF presure

[dartagnan]

Last week due to the extreme cold weather i turned the central heating water temp up at the boiler a bit thinking the rads could do with getting a bit hotter.
This resulted in the pressure going up a bit and opened the PRV which then resulted in it leaking slowly.
i've managed to reseat it by opening it and letting it release quickly on its own spring tension.

My questions now are.

After refilling the system to .7 bar cold, the presure goes up to about 2.8 bar when fully operational, "It may have done ths before"
Is this too high.

Will the expansion vessel need re-presurising

How do you presurise the EV.
Is it through the Auto air vent at the top of the boiler unit that is accesable or
Through what looks like a shrader valve on the EV that is in-accesable.

Ive no problem will calling in a pro if ness and will do so if the PRV starts leaking again as it looks a sod to get at, I just want to check out all options I can do myself

 

[tomy]

it i8s through the schrader valve but the heating has to be drained first .

 

[dartagnan]

I thought it must be the shrader valve, but how do you get at it.It looks like a major stripdown

 

[dartagnan]

Well after trawling the internet inc diynot, the overwhelming opinion seems to diagnose a Pressure Relief Valve that wont reseat properly after being activated and a new Expansion Vessel that has water dribbling out when the shrader valve is released.
Not a job for the faint hearted on this model boiler, so I called in a Gas Engineer, I left him a note of the symptoms etc and left it for him/her to diagnose and fix while I was at work.

He was there for about 2.5 hrs and ended up draining down and replacing the pump. The old pump was a little bit noisy, but not much, although I have no doubt it was ready for replacing
He has set the CH temperature a bit lower than I had it, The boiler pressure is set to about 0.8 bar cold and goes up to about 1.7 bar when Hot.
All seems perfectly ok now, and I would say never been better and all Rads are nice and warm.

My question to all you experts is.
Is this unusual as all the web sites I visited never mentioned a possible pump problem
Im thinking that maybe the pressure built up when hot to 3 bar because the water wasn’t flowing properly due to a dodgy pump, could this be right.
Does it still need an expansion vessel as water defiantly dripped out of the shrader valve.
Has he tweaked something to overcome the possible problem of a faulty expansion Vessel

 

[landyandy]

Your first post would indicate to me that your ev is faulty. Water out of the ev valve. No where for the expansion to happen so out of the prv.

Pump change. Not sure.

Maybe repressurising the ev has given you some time. Only for your original problem to re appear. Time and how bad your possible faulty ev will tell.

Andy.

 

[nickso]

EV's often give a small amount of water out of the valve. if it's a torrent then it's fecked. on a cdi that is certain doom, there is no one apart from WB themselves that thinks anything other than an external vessel is the proper repair in this case.

the cdi is a turd of the highest order, anything you do to not mess with it is good news, get a competent person to add an external vessel and cap off the current one. job done.

 

[dartagnan]

Thanks for that,
I dont think he has recharged the EV as I cant see any signs of onything being disturbed to get at the valve. its so close to the pipework you can just get the dust cap off. no chance of attatching a pump.

The pump simply bolts on.

I only released the shrader valve on the EV very slightly as I didnt want to loose any presure that may still be in it, Just long enough to see a couple of drops of water

I think its just a matter of wait and see, I dont want the whole boiler stripping if it can be avoided as it about 10 years old now, "if it isnt broke dont fix it" and there is room for an external EV if I need one later.

As I said before all seems to be working fine.