My WB 30CDi combi boiler is losing around 0.5 bar of pressure daily. However, when I bleed the rads, there is no air in the system. What could be causing this? I have the 5-year WB guarantee so i'm hoping it's simply a boiler-related issue and not related to the pipework or rads.
WB 30CDi losing pressure daily but no air in system
- Thread starter taz777
- Start date
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First of all, STOP bleeding the radiators. Each time you do that, you are introducing fresh water into the system which has air in it 20% of which is oxygen. This oxygen needs to eat, so it will be chomping on iron surfaces in your system
ONLY bleed a radiator IF top rib is cold and base rib on the radiator is HOT
The kind of leak you refer to, will show up as a wet patch or wetenss someplace. Check the pressure relief vent pipe for a start. Go look for the leak. Mind you, it could be inside the boiler as well in which case a RGI will need to attend
ONLY bleed a radiator IF top rib is cold and base rib on the radiator is HOT
The kind of leak you refer to, will show up as a wet patch or wetenss someplace. Check the pressure relief vent pipe for a start. Go look for the leak. Mind you, it could be inside the boiler as well in which case a RGI will need to attend
As dp says, check the pressure relief pipework, see if the end of it is wet/ damp.
Secondly to save some time for the rgi and to rule out a leak within the boiler, isolate the central heating flow and return pipes from the isolating valves under the boiler, they are the extreme left, and extreme right hand side pipes. If there is still a pressure drop within 24 hours, then the issue is in the boiler, and time to call worcester out.
If no pressure drop, then problem is on the radiator side.
Secondly to save some time for the rgi and to rule out a leak within the boiler, isolate the central heating flow and return pipes from the isolating valves under the boiler, they are the extreme left, and extreme right hand side pipes. If there is still a pressure drop within 24 hours, then the issue is in the boiler, and time to call worcester out.
If no pressure drop, then problem is on the radiator side.
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If it's not an issue with the boiler, you may get charged.
My monies on the expansion vessel not being charged... Rubber lining perished= no expansion=blowoff running.
Wont have perished but could be faulty. May not have been charged correctly or faulty shreider (spellling) valve. How big is the system? who fitted the boiler? ( vessel undersized maybe?)
Anyways all the points of failure have been expressed.
Anyways all the points of failure have been expressed.
Oh well, it's the worst case scenario for me. The WB engineers was satisfied that the boiler wasn't leaking. The original CH installers are coming out next week to take a look - something i'm dreading as I have no confidence in their skills.
We were telling you that it would not usually be a boiler manufacturer's fault although it could be an installer's error.
Did the Worcester engineers charge you for their visit? They have every right to do so and most manufacturers will!
Why do you have so little confidence in your installers? After all you chose them!
If the pipework was the original, and particularly if it was previously open vented, then it could well be a leak in the original under floor pipework which is not, per se, the installer's fault.
Tony Glazier
Did the Worcester engineers charge you for their visit? They have every right to do so and most manufacturers will!
Why do you have so little confidence in your installers? After all you chose them!
If the pipework was the original, and particularly if it was previously open vented, then it could well be a leak in the original under floor pipework which is not, per se, the installer's fault.
Tony Glazier
No charge from the nice WB engineer. 
My original CH installers were the installers from hell. A verbal quote of £3K for a basic CH system in a 3-bed semi ended up costing me £7K.
As for no confidence in original CH installers:
No room/house sizing, no BTU calculations to size the rads, no Powerflush even though I was charged for this, five weeks of further visits at the end of the job to rectify other issues, couldn't diagnose blocked filters in newly-installed shower - costing me £1,100 to get a new water mains poly-pipe as they said it would fix the pressure issue. I then paid a proper plumber a further £120 to clean the filters in the new shower as the original CH company didn't flush the pipework.
The workers would just step into my bath with their heavy work shoes and scratched it up badly. The pipework was all experimental and they eventually capped off a lot of their pipework when they couldn't reach under the kitchen cupboards properly. This cost me a further £500 to have a proper plumber reduce the pipework by eliminating all the redundant pipework.
Each room had around 2-3m of trashed floorboards after they left.
The boiler wasn't commissioned properly. And now the WB engineer has stated that my mains gas flow rate is below the minimum rate required for the WB 30CDi boiler.
And finally I have a leak in the CH system - this is going to cost me £350 to fix.
My original CH installers were the installers from hell. A verbal quote of £3K for a basic CH system in a 3-bed semi ended up costing me £7K.
As for no confidence in original CH installers:
No room/house sizing, no BTU calculations to size the rads, no Powerflush even though I was charged for this, five weeks of further visits at the end of the job to rectify other issues, couldn't diagnose blocked filters in newly-installed shower - costing me £1,100 to get a new water mains poly-pipe as they said it would fix the pressure issue. I then paid a proper plumber a further £120 to clean the filters in the new shower as the original CH company didn't flush the pipework.
The workers would just step into my bath with their heavy work shoes and scratched it up badly. The pipework was all experimental and they eventually capped off a lot of their pipework when they couldn't reach under the kitchen cupboards properly. This cost me a further £500 to have a proper plumber reduce the pipework by eliminating all the redundant pipework.
Each room had around 2-3m of trashed floorboards after they left.
The boiler wasn't commissioned properly. And now the WB engineer has stated that my mains gas flow rate is below the minimum rate required for the WB 30CDi boiler.
And finally I have a leak in the CH system - this is going to cost me £350 to fix.
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