Boiler gurgling noise on HW cycle only

[longshanks2]

Hi,
I have poterton prima boiler and cylinder system regularly serviced, the problem is that when the HW cycle only kicks in there is a lot of gurgling noises and the sound of trickling water comming from within the boiler this continues whilst the water is being heated. I have just had it serviced and had a new auto air vent valve fitted the engineer said that the sound is caused by air within the system and should settledown after a couple of cycles, well day two and it sounds worse. My question really is why does this only occur on the HW cycle.

 

[Dan Robinson]

the system is probably incorrectly piped.

 

[longshanks2]

Thanks for that, this is not a new installation so the pipework has been there for a long time at least 20 years, just had it serviced and a new air valve fitted this involved a partial drain down and this has made the sound problem worse. I am thinking maybe air has been drawn in during this process and will eventually vent out, or at least that is my hope.

 

[Dan Robinson]

Seen plenty of 20+year old systems piped wrongly.

 

[Scarum]

Try turning pump speed from min to max for a few seconds and repeat, it might force the air out.

 

[longshanks2]

Thanks for advice I have tried that, I am now thinking about putting a cleaning agent through the system although there is already A sentinal X300 in there and has been for a number of years. maybe a draindown and flush ect, advice on what cleaner/descaler to use, the system is 35 years old