Pressure loss in Worcester Greenstar 40CDI Conventional Boiler

[approach]

Hi
I have a Worcester Greenstar 40CDI Conventional boiler. The boiler and CH system is just under 2 years old and never caused an issue but has suddenly become prone to pressure loss .
A recent radiator removal and draining of system was taken 2 weeks ago with no problems up until 2 days ago.
We have checked for leaks on rad valves and visible pipe work. We have lots of oak flooring and tiles down so we have run the downstairs independently, likewise upstairs and had no pressure loss which hopefully indicates we do not have a leak in the pipe system.
There is no water coming from the external pipe from the pressure vessel which suggests that is functioning correctly.
If the Hot Water & heating are run together we get no pressure loss. As soon as we switch to just Hot Water we get a pressure loss of up to 1 bar over an hour. This also happens when we switch the HW off and run the heating independently.
Overnight with no boiler activity we get a total pressure loss.
This maybe not be an issue but the emission/steam coming from the external flue smells of inhibitor? I have not noticed this before.

All rads are bled with no air present.

Hope someone can help.
Thanks :mad2:

 

[diamondgas]

It sounds like you could have a leaking heatexchanger? The leak would not be noticeable as it'd go straight down the condensate pipe. That would also explain the exhaust fumes smelling of inhibitor

 

[approach]

Thanks.

I have noticed a flowing noise through the condensate pipe and it is very warm to touch (right up to the soil waste outside). additionally i noticed an increase in steam from the flue . Would this be normal? Sounds as though a call to Worcester might be advisable.

 

[diamondgas]

It isn't normal to have a constant flow down the condensate but it may warm up when the syphon 'dumps'. If it's still under warranty then yes I'd be calling Worcester out. They'll be able to verify whether or not the heatexchanger is leaking

 

[mfgs]

It does sound like the heat exchanger is leaking to me to. The heat exchangers have a 10 year warranty, very strange for it to fail in under 2 years though. You dont have a water softener on the incoming mains do you?

 

[approach]

No softerner installed, although we could do with it as our area suffers from hard water!

 

[approach]

Sorry, just recalled we have an electolytic inline scale inhibitor on the mains.

 

[mfgs]

Worcester state in the instructions that artifically softened water should not be used to fill the heating system and it can cause the heat echangers to leak. A friend of mine found out the hard way when he fitted a boiler in a house with water softener which he never knew about, the heat exchanger only lasted 6 months.

 

[approach]

Ok thanks for the info.