Worcester Bosch Greenstar Pressure Problems

[jsaipe]

Hi, I have a Worcester Bosch Greenstar 24i boiler with strange pressure fluctuations.

For the last couple of days I noticed that the pressure was reading zero in the morning when cold. I also noticed a slow drip coming out of the drain valve thanks to it only being hand tight.

So, I assumed that the pressure had dropped due to the water leak (albeit small). After tightening the drain valve I re-pressurised the system (when cold) back to 1.

However, when the boiler is on, the pressure goes up to 3 bar and into the red. To reduce the pressure, I've bled the nearest radiator when the boiler is on (not sure if I should do that while the boiler is running?). And then it sits happily around 1.5-2 bar.

However, when the boiler has been off for a while, the pressure is near enough back to zero after cooling right down which has forced me to re-pressurise to get the pressure back up to 1.5.

I've been through this process a few times of re-pressurising when cold but then having to reduce the pressure when hot.

I'm not especially technical, but from what I've read could it be my expansion vessel? Or could there be trapped air causing this? (FYI I've bled most of the radiators and none at the time had air in them).

Any help would be appreciated.

 

[EPH]

It's the expansion vessel, might just need re pressurising though rather than replacing.

Drain the system and check the pressure using a tyre pressure gauge on the top its just under the flue if it goes straight out the rear. Look at the right hand picture below, its at 1 o'clock on the vessel as shown.

It should be about .75 bar. If its less use a pump to increase the pressure accordingly. If you can hear air going back into the system or the pressure keeps dropping it needs replacing. You can cut an additional one into the boiler return pipe but if its the original one being replaced you MUST have a GSR engineer to perform this task.

 

[jsaipe]

It's the expansion vessel, might just need re pressurising though rather than replacing.

Thanks! Will check it out. For an amateur it sounds a bit daunting.

FYI Worcester Bosch have quoted £260 to come out and fix or replace. Sound like a good deal?

 

[Dotty]

Repressuring your EV is NOT advised as above as you don't know what pressure to put in it. Also there are other things you need to check and do.

The fixed price repair price doesn't sound too bad. Ring a couple of local gsr's too. There's more than one way to skin a cat!

 

[Centralheatking]

Why use a W/B expansion ? generic external ones are about £40 - cap off the boiler one and stick the new one some where else with a 't' joint - thats what I would do - BUT GET A QUALIFIED
FELLA IN TO DO THIS ..............CHK

 

[bert large]

If it's a Greenstar Junior the expansion vessel will probably be knackered. I've had to replace two in as many weeks.

 

[Centralheatking]

I have looked thro our records - the 24i has not been a great performer -

I can see 20/25 installations and the call backs etc make me pleased
that we dumped it and moved on - it was cheap at the time CHKing

 

[EPH]

Also, the PRV is a pig to change on these. .

 

[jsaipe]

Thanks all for your contributions. Really appreciated.

I have Worcester Bosch popping over on Tuesday as I'm not qualified to fix it. I was told this boiler was a star performer a few years back when it was installed. Hard to know who to believe eh!

 

[Ermintrude]

Thank Worcester for everything .

Now If Carlsberg made a boiler it would be as light as a logic, beautiful as a Worcester, reliable as a valliant, have as many parts as a intergas, be priced like a heat line in rays super clear out offers and have a pay back scheme like Baxi. It would also make tea to go with the free bickies !

 

[Koogatubac]

I believe the 'best' boiler is different plumbers opinions.

This topic on the 'best' boiler has been covered sooo many times