central heating problems

krishing

hi plumbing people
i have a baxi bermuda back boiler supplying heat to 7 radiators in my 2 bed house. i have these problems

1 air is getting into the system which is sometimes noisey as a couple of the radiators emit a rattling and chugging noise

2 the radiators get pretty hot farily consistently all over but seem incapable of raising the temperature over 17 centigrade when it is cold. this may be because the boiler cuts out periodically

the boiler should supply hot water to the cylinder (upstairs) but does not. this may be because i asked an engineer a while back to shut off the supply as i rarely needed it (i have a shower unit) i can't remember! the sytem does not allow water heating independent of the central heating. the engineer who serviced it recently didn't seem to think it was possible to shut off the supply to the cylinder - perhaps there is a blockage. i don't know where the pump is located but i'm told it may be under the floor boards. i am told by (contractors) that a power flush is needed, but it seems to me the starting point is to stop air getting in. i'd be pleased to hear any comments. thanks in advance
krishing

glitzy

Wow i cant believe it i thought i was the only one with of those antiquated boilers. I am going to state the obvious - have you bled the radiators? admittedly if your rads are like mine, you cant bleed them all as they have broke. Did not know you could seperate the heating from the water, but have got operating instructions which state 'provide heating and also domestic hot water if required' plus not sure if this will help TO LIGHT THE BOILER PILOT - 1-remove the fender - instructions on fender.
2-hold in grey button
3- push igniter button repeatedly until pilot flame alight,
4-continue to hold grey button for 15 secs -
5-release slowly & pilot should stay alight

krishing

glitzy
many thanks for your reply. yes i've had to bleed the radiators all too often. the pilot works ok. getting the house in order for renting so nic electric certificate required i'll get the electrician to look at separating water and heat.
regards
krishing