gloworm swiftflow 120 loosing boiler pressure

[drewbie]

hi i have a gloworm combi swiftflow 120, the problem is that it keeps loosing pressure. at first i thought it was the pressure release valve that maybe wasnt sealing properly so replaced it for same type but its still venting. i have noticed that when pressure has been set at 1 bar while just usinhg the boiler for hot water its fine but as soon as you put the central heating on the bar pressure steadily climbs until it reaches 3 bar then of course the valve opens and it starts to vent, i think the pumps running [grundfos] i have tried to listen to it as i change the speed and it changes in tone.......can any one help pleaaaaase.

 

[nickso]

the expansion vessel needs to be pumped up with air or its burst or the pipe leading to it is blocked

 

[drewbie]

have just pumped up tank to 10lb what is the correct pressure please

 

[drewbie]

the expansion vessel needs to be pumped up with air or its burst or the pipe leading to it is blocked

 

[nickso]

it needs to be pumped up to 1 bar

the prv must be open when you pump it up

 

[drewbie]

if i open the prv the water drains out and goes to 0 do i then pmp it up? need idiots guide please

 

[nickso]

yes

if you pump it up with water pressure in it you wont get it to the right pressure no matter what it says on your pump guage

 

[Gasguru]

Pump the vessel to 0.8 Bar with zero pressure showing on the boiler pressure gauge. Ie open the safety valve while you are pumping it up.

Once the vessel pressure is OK remove the safety valve head and clean the seating otherwise it won't seal properly once you re-pressurise the boiler.

Check the auto air vent doesn't leak after all this otherwise you need to change this as well.

 

[drewbie]

i dropped the pressure down to 0 using prv but when i trid to pump up with valve open it would not work so closed the valve and pumped to .8 bar top upto 1.1 bar using top up pipe and turned on heating the pressure valve climmed to 1.6 bar but is holding so i think your advice has helped to solve it, i will check it out in the morning, thank you andrew

 

[Gasguru]

You have to measure the pressure on the expansion veesel ie where you connect the pump.

 

[drewbie]

i am only using a bike pump, the gauge i have measures in lb how do i get 1bar?

 

[ChrisR]

1 bar is 15psi

Procedure is explained in detail in faq section "Boiler Pressure Problems"

 

[drewbie]

thanks for that have read it all and now filled boiler correct way, pressure levels out at 1.5 bar when running and prv not leaking but pressure still drops back to .2 bar when heating is not running and has been left awhile, any more help please