Boiler gargling noise

[kevoffthetee]

Hi all

Last week I had a heating engineer out to sort a pressure problem. He added an external expansion vessel to the ch return and then a replacement water pump.

Every now and again as the boiler fires up the pressure gauge flickers and then a huge gargling noise comes from the boiler and it cuts out. Turn the boiler off for a while and then back on and everything is ok again.

I can only resemble the gargling sound to when you empty the bath.

Could you guys shed any light on what it could be and is there anything I can do myself as I can't get him back out until Tuesday

Thanks, Kevin [/url]

 

[kevoffthetee]

Should the heating engineer have isolated or repressurized the original expansion vessel?

The system started making the gargling noise again and I've located that it is coming from the original expansion vessel.

 

[1983]

This could just be the old exp vessel filling up with water, can't think of anything else that would cause a gurgling noise. Is the pressure gauge flicker happening when the gurgling noise happens.
It's not necessary to disconnect the old vessel.
Is the pressure ok, ie it doesn't go too high(near the 3 bar mark) or too low?

 

[kevoffthetee]

Hi 1983,

The pressure is stable at 1 bar before and after the pressure jolt and gargling noise.

It happens randomly and seems to be mainly when the system fires back up when idle for an hour or two. The system is running quiet and I've checked for air in the system at the rads and the release screw in the middle of the pump so I'm lost for ideas

 

[1983]

Does sound like its just the water making its way into exp vessel, if the vessel was empty of water and no charge when the system is pressurised the air in it will be trapped. The water then could bubble into the vessel as the air is under pressure. The diaphragm in the vessel was probably holed.
Best get him to check it anyway but this will probably disappear in time. He could also bleed the old vessel through the valve to get rid of air.
Edited to say what make and model of boiler is it?
Possible air is circulating in system also.

 

[kevoffthetee]

My heating engineer managed to finish a job early today so called in when on route to another job. He said that he hadn't tightened the bleed screw on the new pump and that's what was allowing air into the system

Will see how things go as I'm still not 100% on this causing the problem, but we'll see