Hi all
I have a problem with my central heating system. It has been the same for the last 3 years when I moved in.
There is air (a lot - about 1/2 radiator) in 3 of the upstairs radiators. I can bleed most of it out, but not all. I’ve tried bleeding with the pump on and off. I’ve also turned off the individual outlet valves on each rad to get more pressure in the push the air out (returning them to normal afterwards). Sometimes there even seems to be negative pressure in the rads – hissing noise but you can’t feel the usual outflow of air. So there seems to be something of a lack of pressure in the system. The header/expansion tank is full, although I can feel some sludge at the bottom of it. The pump seems to be working ok, and I’ve tried it at all 3 speed settings. I also tried bleeding the pump (screw in centre) but didn’t get anything.
Having got most of the air out of the rads, the next morning when the system comes on, there is the most almighty gurgling in the system waking up the entire house for a good 30 minutes. The gurgling seems to be from the inlets of the radiators affected, but sounds like it may be in the loft too (where the expansion tank is). I tried to place the loft sounds exactly, and they actually seem to be from the cold water tank rather than the expansion tank.
After a few days of leaving the system alone, it settles down and is quiet, albeit with half-full (and thus not hot enough) radiators.
If I bleed the rads again, I get the morning noise problem again.
Is it possible that the system is somehow syphoning water back into the header tank? If so how do I stop this?
Thank you for any help.
Chris
I have a problem with my central heating system. It has been the same for the last 3 years when I moved in.
There is air (a lot - about 1/2 radiator) in 3 of the upstairs radiators. I can bleed most of it out, but not all. I’ve tried bleeding with the pump on and off. I’ve also turned off the individual outlet valves on each rad to get more pressure in the push the air out (returning them to normal afterwards). Sometimes there even seems to be negative pressure in the rads – hissing noise but you can’t feel the usual outflow of air. So there seems to be something of a lack of pressure in the system. The header/expansion tank is full, although I can feel some sludge at the bottom of it. The pump seems to be working ok, and I’ve tried it at all 3 speed settings. I also tried bleeding the pump (screw in centre) but didn’t get anything.
Having got most of the air out of the rads, the next morning when the system comes on, there is the most almighty gurgling in the system waking up the entire house for a good 30 minutes. The gurgling seems to be from the inlets of the radiators affected, but sounds like it may be in the loft too (where the expansion tank is). I tried to place the loft sounds exactly, and they actually seem to be from the cold water tank rather than the expansion tank.
After a few days of leaving the system alone, it settles down and is quiet, albeit with half-full (and thus not hot enough) radiators.
If I bleed the rads again, I get the morning noise problem again.
Is it possible that the system is somehow syphoning water back into the header tank? If so how do I stop this?
Thank you for any help.
Chris