baxi 552 only lukewarm, pump problems ?

[totty]

Hi,

I've recently bought a excouncil house that has been empty for a while, at some point (probably while empty) it had a baxi back boiler and fire installled which appears to have never been used. The house needs allot of work and I'm on a tight budget so I'd like to do as much as possible myself.

I've found that when set to water only it works fine but when the heating is on the boiler gets quite noisy and both the water and the radiators (and the pipes from the boiler) only get lukewarm at best after running for 3 hours.
So far I've read loads of posts on various forums (unfortunatly with a hang over which cant of helped, but it is nearly xmas and done the following:

checked that the tanks (large tank with a smaller one fixed to the side of it) in the loft have water in them.
blead all radiators (loads of times)
found that the taps either side of the pump were turned off.

I've done a bit of experimenting with the taps and opening them any amount cures the boiler noises. The less open they are the hotter the pipes get, but I still cant get the radiators hot just warm. I also don't think this is the correct way to adjust the flow but I havent found any controls on the pump (It's quite hard to get at) a collegue has also just suggested that I might not have a pump suitable for microbore, they may have replaced the pipes but not yet replaced the old pump and that might be why the taps were turned off.


Has anyone got any ideas what to try next ? new pump maybe ?


Thanks

Allan

 

[breezer]

have you bled the pump?

 

[totty]

Hi breezer, thanks for the reply.

No, I didn't know you needed to and I havent spotted a bleed screw on it. Its on a vertical pipe as well so I would have thought that it wouldnt need bleeding ?

 

[oilman]

There may be other bleed points not on radiators. The pump bleed is usually a large screw on the back of the pump.

 

[ChrisR]

Look for a bleed point near where the boiler's pipes go into the hot water cylinder. Pump's valves should be fully open. Pump probably has 3 speeds, set on the plastic block part of it. Does it run quietly?

 

[totty]

I had a look for bleed points at the tank in the loft and I couldnt see any but I'll double check tomorrow. I thought they should be fully open but I wasnt certain, thanks for confirming. The pump runs fairly quietly, you can only here it if theres no other noise in the house. I think I might have to take the pump out and have a good look at it, it's only got a few mill clearence on most sides. Once I've found a speed control, whats the precedure for working out which speed to use ? Shall I just turn it down 1 ?

Thanks

Allan

 

[totty]

I've now turned the pump down to I from II and blead absolutly everything. Unless anyone can suggest anything else to try I think its time to give in and call a pro.

Thanks

Allan

 

[DP]

Goto CORGI website and look for registered gas engineer under 'boiler' sunsection to get one who is registered to work on boilers.