Air Entering System / Pressure Drops

[Ksite]

Hi All

I have recently had a Worcester Greenstar Condensing Boiler installed, but have recently noticed that my upstairs radiators need bleeding once every week or so (and then the boiler topping up)

The rad starts out hot all over, then gradually gets colder starting in the top left, before the 'coldness' spreads all across the top. Bleeding solves the problem temporarily.

I also noticed that over a similar period the pressure on the boiler dropped from 1.5 bar down to 1 bar.

I assume air is getting into the system somehow - but the CORGI who installed the boiler has been back twice and just bled the rads - I can do that myself!!

I've read somewhere that it could be the system was not flushed on installation of the new boiler, or that it has not been balanced correctly? Or that I have a leak somewhere in the pipework.

Any suggestions gratefully received - I'm worried about returning home to find myself with one ceiling less than I should do and water everywhere!

 

[OilLecky]

I only work on oil appliances but I'm fairly sure that the hot water system is the same.
How about this? The Pressure Relief Valve (PRV) is leaking slightly. It is the part usually with a red plastic knob that may have something like 2.5 or 3 bar written on it. It vents outside the house. Put a balloon over the outlet and see if it fills with water. If it does then it is leaking. What happens then is that, over-night, when the water cools, air is drawn in through the faulty PRV. This gives you both low pressure on the gauge and air in the radiators.