Can't figure out whats wrong

Hi , This is my first time writing in looking for help. I can't get someone to check out my central heating , its boomtime in Ireland and impossible to get anyone to come to the house without waiting weeks.

My main problem is a lot of the radiators are cold at the bottom and either warm or luke warm at the top. The small rad in the ensuite is'nt working at all ! All the rads are fitted with TRV's which I've checked and am pretty sure they are opening. The system is about 12 years old , the gas boiler is a Potterton , wall mounted job. Up in the attic I have two big water tanks and one small one sited directly over the two big ones. One of the big tanks and the small one have ballcocks attached to them.

Attached to the copper cylinder in the airing closet is a red expansion vessel about the size of a football , however there is no pressure gauge in there or anywhere on the boiler , so I'm not sure if its a sealed system or not.....my neighbour has exact same system but has a pressure gauge.

I've bled the radiators several times and no air comes out and the water is very clean . I've shut off several radiators at a time to put pressure on the remaining rads but it made no difference. I've also experimented with a couple of the lock shield valves in case it was a balancing problem. I've just been advised by someone that the problem is that I need a new expansion vessel , I've looked through pages of letters in the forum but do'nt see anyone writing to say they've had to change one or suggesting someone should get a new one so I'm a bit sceptical that thats the problem. I'm getting so much conflicting advise from people I'm not sure where to go now, however, I'm determined to get those TRV's off as I do'nt trust them , to do that I'll have to drain the system so if I'm doing that should I get a new expansion vessel and why have I no pressure gauge.

Sorry about the length of the post but wanted to tell you as much history as possible .

Many thanks

Which pipe on the HW cylinder is the red vessel attached to?
Red implies it's for heationg rather than tap water. Is the small tank in the loft definitely in use?

Rads being cool at the bottom is either due to sludge, or just not enough hot water getting round. Than can be becaause the pump is worn out or blocked, or the boiler isn't producing the heat it should.
Does the pipe from the boiler get good and hot?

You dont say exactly where you are. There are several people here in your country.

I really dont think its necessary for you to wait weeks unless perhaps you want to!

Tony

ChrisR ,

Thanks for your reply , a pipe comes out of the red vessel which then connects onto another pipe (pipe A). Pipe A runs parallel to the HW cylinder , one end of the pipe dissapears downstairs the other end comes to a dead end. Just before it come to a dead end a pipe comes of it and goes into the side of the HW cylinder near the top.

The small tank in the attic works OK , there's a pipe coming out of the boiler which is very hot alright and theres no problem with hot water from the taps ,the boiler was serviced at the start of the year and a friend has already had me check that the pump is turned up all the way.

If there was sludge would the water coming out of the bleed valves be dirty ? , as it is they are all clean.

Regards.