Replacing Pressure Relief Valve

[PlumberNot]

Off to bed now - work in the morning

Will respond in the morning guys - thanks

Outside pipe still dripping - Pressure still on 1 bar

 

[ChrisR]

1
Looks like top, rear

2 Nope, leave that alone!
3 Not necessarily - gravity an all...
4 just twist the head of the prv. Probably red, but recently black.
5 Aye

 

[PlumberNot]

Just squeezing in a sneaky bump on this topic at work

When I get back from footy I shall do the following:

Please correct me if I am wrong

1. Turn boiler off
2. Locate the Pressure Vessel Valve
3. Press centre pin - if air comes out - ok [can recharge as in FAQ]
if water comes out - expnasion vessel knackered? needs replacing?

I will post upon checking the expansion vessel first before proceeding.

Meanwhile - is there any significance that the pressure is remaining around 1 bar even though it is still dripping out of the pressure relief pipe. I have not put the heating on - only used hot water

Can I turn the relief pressure valve to close it?

Thanks

 

[corgiman]

Just squeezing in a sneaky bump on this topic at work

When I get back from footy I shall do the following:

Please correct me if I am wrong

1. Turn boiler off
2. Locate the Pressure Vessel Valve
3. Press centre pin - if air comes out - ok [can recharge as in FAQ]
if water comes out - expnasion vessel knackered? needs replacing?

I will post upon checking the expansion vessel first before proceeding.

Meanwhile - is there any significance that the pressure is remaining around 1 bar even though it is still dripping out of the pressure relief pipe. I have not put the heating on - only used hot water

Can I turn the relief pressure valve to close it?

Thanks

MMmmm

is the pressure remaining constant while heating the rads, or does it increase?

 

[PlumberNot]

I'm having great difficulty trying to locate the pressure vessel valve

Where is it on the diagram?

Corgiman - got back from football still 1 bar ressure and dripping outside

Have turned on heating now - will let u know re: pressure in 5 mins

 

[corgiman]

thats not right

something is letting by

the PRV should only open @ 3bar and empty the system

not start dripping at 1 and never dropping

mmmmmm rum

 

[PlumberNot]

heating is now on

pressure has rose about 2 tenths of a bar - showing 1.2 bar

radiators are on

outside is still dripping.

-------------------------------------------------
The thing is when the boiler first lost pressure - I kept topping it to 1.3 bar and it would fall to below 1 bar over a day or so. After I had heating on for a couple of hours one night and bleeding a couple of radiators - I topped it up to 1 bar and its remained there since even though it's dripping outside?!!

 

[corgiman]

then I dont reckon you expansion vessel is at fault at all

but something MUST have opened the PRV in the first place

cor I would so prefer to have a look sometimes I cannot do this over the t'net

 

[kevplumb]

I topped it up to 1 bar and its remained there since even though it's dripping outside?!!

then something is filling it as fast as it is dripping

 

[corgiman]

I topped it up to 1 bar and its remained there since even though it's dripping outside?!!

then something is filling it as fast as it is dripping

thats what I was was thinking pappy

but surely if the filling loop or DHW HE was letting by wouldnt the pressure stay at 3 permanently???

 

[kevplumb]

not if the prv is letting by at the same rate give or take

 

[PlumberNot]

what shall I do then?

Shall I change the PRV and see what happens?

I understand that [logically] something must be filling it up if it is remaining at the same pressure.

I have turned off the heating and the pressure has since fallen by one tenth of a bar. I have checked that the filling loop key is turned off

Any ideas

 

[clf-gas]

Not seen this before on W/B

Corgiman and Kev, Your dead right.

Plumbernot, switch of the call for heat on the boiler, issolate the flow and return at the bottom of boiler, observe the pressure for 30min.

Has the pressure dropped?, open the issolation valves to flow and return, observe for 30min, does the pressure rise or stay the same?

Think you filling loop is passing causing initial rise and release, now prv is passing also.

will need to replace both.

 

[PlumberNot]

Plumbernot, switch of the call for heat on the boiler, issolate the flow and return at the bottom of boiler, observe the pressure for 30min.

Please explain - do you mean turn heating off, turn water off

 

[clf-gas]

Yes turn the heating off.

Issolate from bottom of boiler, flow on the left return on the right.

also the cold feed second from right, blue knob