Pipes/Pump - Quiet with CH, Noisy with HW

steve99

My update to this is that I left the system running as normal until July but the noise never went away. I had my boiler serviced around then and the engineer advised putting Fernox Leaksealer F4 in and trying a new pump. I did both and the noise just got worse. I then flushed the system by leaving the header tank filling valve on and draining through the drain radiator drain off valve. The water now is pretty clear in the system and I bled as much air as i could through the rads but the noise is still there and even worse than before. It seems to come mainly from the pipe that goes to the header tank in the airing cupboard. I even reduced the water level in the header tank in the hope that any air would be more likely to escape if there is less water in the tank and i did see a few bubbles but it's made no difference.
I'm about out of options now and winter's on it way.......

southcoastrgi

steve99 wrote: »

My update to this is that I left the system running as normal until July but the noise never went away. I had my boiler serviced around then and the engineer advised putting Fernox Leaksealer F4 in and trying a new pump. I did both and the noise just got worse. I then flushed the system by leaving the header tank filling valve on and draining through the drain radiator drain off valve. The water now is pretty clear in the system and I bled as much air as i could through the rads but the noise is still there and even worse than before. It seems to come mainly from the pipe that goes to the header tank in the airing cupboard. I even reduced the water level in the header tank in the hope that any air would be more likely to escape if there is less water in the tank and i did see a few bubbles but it's made no difference.
I'm about out of options now and winter's on it way.......

oh dear another cowboy engineer, why put leak sealer in there to gum everything up inc your boiler from what you say you don't have a leak & if the heating works fine then you prob didn't need a new pump.

it looks like a combined feed & vent teed into the boiler flow under the pump, the vent should rise upto the header tank but because it is on the side of the pipe it is never going to be any use for venting air as any air will just bypass the tee & go straight up into the pump & round the system

steve99

southcoastrgi wrote: »

it looks like a combined feed & vent teed into the boiler flow under the pump, the vent should rise upto the header tank but because it is on the side of the pipe it is never going to be any use for venting air as any air will just bypass the tee & go straight up into the pump & round the system

There is just one pipe that is connected to the input to the pump and then goes up for about 1m. It is then teed as you say with one pipe going to the vent and the other to the feed.

Can you make any suggestions as to what I can do?

Steve

southcoastrgi

yours isn't the only one piped like that i've seen loads (inc one exactly like yours that i'm going to re-pipe next wk), air rises so it's going to go straight up it's never going to go sideways & up the vent, the vent/cold feed is before the pump ie on the neg side which is correct but really the vent should go straight up the only way for that on yours is re-piping it & if i was doing it i would use an air seperator, flow pipe goes up in the a/c to the air seperator, vent off of the top of that with the pump pumping down to the mid pos valve.

keystone

steve99 wrote: »

Can you make any suggestions as to what I can do?

Post a pic or two.

Cheers

southcoastrgi

keystone wrote: »

Post a pic or two.

Cheers

post no 17 KS

keystone

southcoastrgi wrote: »

post no 17 KS

Doesn't really help me as I asked the "combined feed and vent" question at the time and suggested the piping might need adjustment then. I'd like to see more of the pipework tbh.

Cheers

Canucklehead

Hi.

You will get nowhere until you have it repiped to get a vent on the cylinder coil side of the 3 port.

GSR.