Central Heating Help

[gregor0227]

Hi,

Hoping for some problem diagnosis for my central heating system. Background is:

Vented system
Baxi Bermuda 552 Back boiler
Hot water working

I recently switched my heating back on after the summer. Upon doing this the radiators all came on, but the pump began making a swooshing noise accompanied by the water stopping every 10 seconds. Radiators were coming on but not that hot.

So I bled the radiators and the pump, and everything was back to normal.

However after around a day the pump started making the noise again and the radiators stopped heating up. I have bled the radiators several times and they always seem to have some air in them.

Basically my question is do I have a leak? If so what are the first places I should start looking? and if not what are the other possibilities?

Thanks,

Gregor

 

[Agile]

Have you checked that the F&E tank has at least 100 mm of water in it?

Tony

 

[gregor0227]

F&e tank has loads of water in it. However water level is below old staining around the side of the tank. Thanks.

 

[PowerFlushAssociation]

If there is loads of sludge in the system (water brown or black) you might have a build-up of hardened sludge, where the down feed and vent pipe is plumed into the return pipe before the pump. The hard build-up can cause air to be sucked down the vent pipe because sludge is blocking the down feed pipe.

How do you know?
From the pump follow the pipes backwards until you reach the down feed or vent pipe. If a magnet sticks to the pipes in this area, you will need to cut if out and clean / replace the pipes. The sludge will, again, slowly build up over time in the same area unless removed by power flushing.

 

[namsag]

Flushing does not cure the cause

 

[PowerFlushAssociation]

We did not claim that power flushing fixes the cause. We said: Cut / replace pipes

 

[olejim]

Well you did say "unless" which implies that it does.

 

[PowerFlushAssociation]

If a lot of sludge is present in the system, the down feed section on open vented systems tend to have hard build-ups of sludge.
If sludge is not present in system this build-up cannot happen, because it is made of sludge.
If you cut it out and clean that section without removing sludge from system, it will build-up again, just like before.
Will probably take years, but it will.

 

[gregor0227]

Thanks for replies for far folks. Checked with magnet against pipes from pump up to feed in. Nothing doing. Please let me know if there is any other info which would be useful to diagnose this.

Cheers

 

[gregor0227]

Hi folks,

Thanks for your help. I thought i would post an update to this central heating saga....

Since my last post I have discovered that around 15mins after I switched on the heating, the overflow out the back of the house was overflowing, the radiators had lots of air in them, and the pump was making a swooshing noise.

Following a bit of digging about on the boards I concluded that my pump was "overpumping", and as such I turned it down a notch. This seemed to fix everything...for a while.

Around 5 days later the same problems as above started happening again.

This morning I have turned the pump down to the lowest setting, and it appears to have fixed problems again. However I wonder if I am just putting off the problem rather than dealing with it by doing this?

Can anyone suggest anything further?

Thanks,

Gregor