Combi 80 problems

[rolyatescort]

hi guys, my central heating system is powered by a Potterton Combi 80 that is situated in the utility room on the ground floor at the very back of the house extension with the header tank(s) in the original loft space. it is a mid-terrace with ground and first floors only. The system feeds 2 small radiators and 6 medium sized radiators. The system was installed 3 years ago by a professional plumber but prior to my purchase of the property. The house has never been sufficiently warm but as it is my first experience of central heating i have limited knowledge. After getting a heating guide from B&Q i worked out the BTU rating of my rooms and found each of them to have radiators that weren't powerful enough. I checked with Potterton who confirmed that the radiators when added together were below the recommended minimum setting of the boiler so it was fine to add more powerful units. A professional plumber swapped the original single from the bathroom with a Henrad/Stelrad double convector which i was very happy with so i decided to do the same in the master bedroom again fitted by the plumber this again made noticeable improvements but the system has developed a problem where the pressure drops on the system and the bathroom radiator goes off, if i manually top the system up (to 3 where as it used to run at 1.5) it comes back on. Potterton have confirmed that the system is still nowhere near its maximum capacity. Has anybody any ideas? Sorry for the length of the post but i wanted to give as much detail as possible, cheers.

 

[taydo]

I think you should call your plumber this sounds like a boiler fault. filling the system to three bar you are getting close to activating the pressure release valve this is not correct.

sorry I cant help you