Pressure loss and bleeding rads

[Bagpuss12]

I've recently had my boiler serviced as mentioned that the pressure was always dropping and I was having to keep repressurising it. The engineer stated there was nothing wrong with the boiler and that maybe the rads needed bleeding? We have a towel rail which always seems to need bleeding and no apparent leaks? Is this right or am I being fobbed off?

 

[easyflow]

Its not right, your expansion vessel has had it.

 

[denso13]

Part fobbed off. There may be nothing wrong with the boiler but bleeding the radiators won't help the pressure loss.

 

[Bagpuss12]

So worth a 2nd opinion then?

 

[easyflow]

Worth a second opinion also how old is boiler and what sort of service history does it have.

 

[Bagpuss12]

No idea on the age but it was in when we moved in 3 yrs ago. We've had it serviced for the past 2 yrs but before that I don't know? Why or how would 2 different boiler engineers not be able to identify an expansion vessel issue?

 

[Madrab]

has the expansion vessel been pressure tested? Or checked if it is filled with water?
You could have a pinhole leak at one of the radiators or within the pipework somewhere.

 

[gigz]

You may have a leak on the system, if your towel rail is highest on the system this is where the air will be getting trapped. Turn the boiler off, bleed all the rads starting downstairs, then bleed upstairs making the towel rail the last one. Pressurise to 1 -1/12 bar, fire the boiler up and watch the pressure guage, it should only get to 2 bar (ish depending on the volume of water) if it goes higher than three its time to check pressure vessel (which should have been checked at service if you told him at the time). Bear in mind the leak maybe under the floorboards/concrete floor. Also have you checked there's no discharge from the PRV ?