Worcester Boiler 24 Losing Pressure

[devon scouse]

Hi
Looking for some advice on problem with Worcester 24 losing pressure.
Boiler serviced in September expansion vessel re pressured and pressure relief valve changed by BG.

Now into December and boiler losing pressure again. Recalled BG on Friday who replaced heat exchanger and pressured vessel again. Said he couldn't do any more that that and if it continues there must be leak in system.

Pressure appears to be dropping again to have placed bag over relief pipe and appears to be dry.

Could the pressure vessel be the problem even though no water coming out off pipe.

Have not noticed any water marks on ceiling

If it is leak in system is it safe to use Fernox leak sealer as all pipework under floor boards.

Many thanks

 

[andytw]

If the expansion vessel has a problem then the water has no where to expand to, so is forced out of the pressure relief valve. As you are not seeing any discharge from the PRV then it looks like the expansion vessel is OK..
I would go around all of the gland nuts on all of your radiator valves and nip them up with a spanner. Also do the same with the bleed fittings if these are the type with a large flat on them. Water can leak from radiator fittings and be evaporated straight off without seeing any wetnesss.
How much pressure are you losing and how often ?

andytw

 

[andytw]

Interesting that you say they re-pressured the vessel "again". Do you mean that, or do you mean they re-checked it ?

andytw

 

[devon scouse]

Many thanks for quick reply Andy

They re pressured vessel. All visible fitting have being nipped again.

Losing about .4bar a day