expansion tank pessure advice

[joesoap1]

Hi Guys. Did as you said .Drained several litres of water off. quite a lot actually, topped EXV up to 1 bar with bleed valve open on rad closest to boiler.Topped system up to 1 bar and run at max temp since 9 am, 13 rads open, several of them doubles.Just reached 82 degrees and pressure is 2.3 bar, so a rise of 1.3 bar.Well below zero here ast night.Checked shraeder valve for leak, no sign of one. Notice sign of leakage at union of diverter valve and DHW heat exchanger, copper coloured furring, and wet to touch cold. No water though. Although PRV just stated to drip last night at 2.8 bar, just a 1/2 a teaspoon in receptacle I placed beneath it.I have been monitoring PRV for signs of leaks for weeks with no sign of it .No leak at PRV today.How accurate my Pump gauge is I'm not sure of:The reason I have never noticed it before is because I have never had all rads on at once in 17 years and always run at 50c, background heat only, possibly 60c max if really cold.It lost 0.5 bar overnight, it fell from 1.5 to 1 bar.Appreciate your advice. RSVP

 

[nickso]

this is a vokera yes? what model?

if its still going that high you could have a blocked flexi pipe.

seems you also have a leak somewhere. could be the heat exchanger if you have no leaks elsewhere.

 

[joesoap1]

this is a vokera yes? what model?

if its still going that high you could have a blocked flexi pipe.

seems you also have a leak somewhere. could be the heat exchanger if you have no leaks elsewhere.

Hi nickso, thanks for reply.I know I have a leak, I.ve had it for years. unable to locate it.It's definitely weeping or leaking hot at the union of the diverter valve and heat exchanger. It. s a fibre washer isn,t it.That's the only sign. No sign in heat exchanger, as I clean it regularly, inside. Got Fernox F4 ready to put in, but advised not to until I did the EXV. It is a Vokera20-80 RS Flowmatic combi.What this flexi pipe, and what rise in pressure should there be?

 

[nickso]

no hard and fast rules on the rise, it depends on the size of the system for a start. 1.3 bar rise sounds excessive though.

the flowmatic has a solid pipe for the EXV, comes off the left side of the left hand manifold. could be blocked and not allowing water though to the EXV. a rare fault on a flowmatic though.

which heat exchanger? the white DHW one? that could be mains water leaking. other places to check for leaks are from the diverter tailplate and if the insulation panels under the main H/E have water marks then that is leaking for sure.

 

[joesoap1]

no hard and fast rules on the rise, it depends on the size of the system for a start. 1.3 bar rise sounds excessive though.

the flowmatic has a solid pipe for the EXV, comes off the left side of the left hand manifold. could be blocked and not allowing water though to the EXV. a rare fault on a flowmatic though.

which heat exchanger? the white DHW one? that could be mains water leaking. other places to check for leaks are from the diverter tailplate and if the insulation panels under the main H/E have water marks then that is leaking for sure.

The weeping and build up of scale is on the left pipe union where the diverter valve goes to white DHW heat exchanger. Not the manifold pump one, one of the 2 @ top of diverter to white vessel.The mini DHW expansion vessel was changed just 3 months ago.I clean inside the main chamber regularly, and main heat exchanger, as I have had wasps build nets inside, causing PCB to short.Never noticed any leakage signs on white insulation foam inside chamber, doesn,t mean I haven't missed it.Thats why I keep it @ 0.5 bar, as soon as I increase it, as I did yesterday, it just leaks back to 0.5 bar, within days. BUT, it doesn.t go any lower, just plods along @ 0.5 bar.What do you think of me using the fernox F4 sealant for the leak?Can this flexipipe be cleaned?

 

[nickso]

The weeping and build up of scale is on the left pipe union where the diverter valve goes to DHW heat exchanger.

sounds like a mains water leak.

it just leaks back to 0.5 bar, within days. BUT, it doesn.t go any lower, just plods along @ 0.5 bar.What do you think of me using the fernox F4 sealant for the leak?Can this flexipipe be cleaned?

up to yourself. i have used it on occasion with some good results. if you are absolutely sure there are no visible leaks it is worth a go if it saves lifting floors. if the boiler plods on with 0.5 bar with no problems i would leave it myself. my own boiler settles to 0.9-1 bar no matter what i put it to, i just leave it now.

EXV pipe can be inspected at pump end but if it needs removing the EXV has to come out i think.

 

[joesoap1]

The weeping and build up of scale is on the left pipe union where the diverter valve goes to DHW heat exchanger.

sounds like a mains water leak.

it just leaks back to 0.5 bar, within days. BUT, it doesn.t go any lower, just plods along @ 0.5 bar.What do you think of me using the fernox F4 sealant for the leak?Can this flexipipe be cleaned?

up to yourself. i have used it on occasion with some good results. if you are absolutely sure there are no visible leaks it is worth a go if it saves lifting floors. if the boiler plods on with 0.5 bar with no problems i would leave it myself. my own boiler settles to 0.9-1 bar no matter what i put it to, i just leave it now.

EXV pipe can be inspected at pump end but if it needs removing the EXV has to come out i think.

Hi, Just looking at manual, the EXV pipe that goes to heating manifold, is that the one you presume may be blocked. If so, wouldn,t it have stopped me re-pressureising it.and just blow off at PRV? I must have got at least 5-10 litres of water out this morning whilst pumping it up.Perhaps a new boiler in spring is called for. Shame, as it.s been a goodun.Would the F4 do any harm to rad valves, It may be a joint under floor where I cannot see.This whole Saga started with my leak enquiry and F4.I think it is the DHW pipe thats weeping from DHW maniflod to DHW exchanger.

 

[nickso]

if you are sure you got water out of the EXV then pipe will be fine.

i don't think a new boiler is needed. certainly try the f4 before that.

 

[joesoap1]

if you are sure you got water out of the EXV then pipe will be fine.

i don't think a new boiler is needed. certainly try the f4 before that.

Cheers nickso, The only reason I am sure is because when I opened bleeder on rad, pressure dropped,to a trickle,I then give my pump a kick, it,s my car pump run off cig lighter, and water shot across the bloody kitchen, and pressure rose in system again.I'll stick F4 in and see what happens. Even if I change boiler in spring. leak has to be fixed first.Thanks for everything. PS. As I am going to put F4 in, and I know there is no inhibitor in, should I put both in together, or F4 first then inhibitor. OR just not bother with inhibitor.????