Hi - We've had on-going problems with our central heating and hot water circuit since we moved in just over a year ago - basically, continuous bleeding of the bathroom rad and hot water vent (next to HW storage tank) has been required to expel air that is getting in somewhere.
I've drained down-flushed-treated (inhibitor on a couple of occasions, DS-3 on another) but still the problem comes back. It seems to be more noticeable on the hot water circuit when the heating is off (which is why we notice it more now as the heating is off for the summer). When the pump starts, you hear some gurgling of water (as though something is filling up) and then you can hear trapped air in the pipes as it circulates.
Last week I came across an article on the Fernox website about see-sawing which seems to fit exactly what we're experiencing (http://www.fernox.com/?cccpage=air_in_CHS&sub=3). I did the first check that they suggested (see if any water is sucked into the open vent pipe when holding a water filled container under it) and half a glass disappeared when the pump came on! I haven't had a chance to do the other check yet as it's a bit more involved, but the nice clean water that was in the tank when I refilled last week is now a dirty brown indicating that some water from the system is getting back into the F&E tank.
When the CH is on, the air in the system does accumulate in the towel rail in the bathroom.
The boiler is a wall mounted Baxi Solo 50/4 RS, pump is a Grundfos 5M (set to 2 at the moment) feeding 8 rads and a HW cylinder and from what I can see the order is: boiler, open-vent, pump, cold feed, diverter (which conflicts with what Fernox suggest). The boiler is in the dining room (was the old kitchen) with the pump and diverter just above it under a trap-door in the floor boards in the bedroom above.
Question is, is the sucking of air through the vent-pipe ONLY associated with 'see-sawing'? If I put things in the correct order suggested by Fernox (boiler, open vent, cold feed, pump) will this problem disappear so I can get on with my life!?
I've drained down-flushed-treated (inhibitor on a couple of occasions, DS-3 on another) but still the problem comes back. It seems to be more noticeable on the hot water circuit when the heating is off (which is why we notice it more now as the heating is off for the summer). When the pump starts, you hear some gurgling of water (as though something is filling up) and then you can hear trapped air in the pipes as it circulates.
Last week I came across an article on the Fernox website about see-sawing which seems to fit exactly what we're experiencing (http://www.fernox.com/?cccpage=air_in_CHS&sub=3). I did the first check that they suggested (see if any water is sucked into the open vent pipe when holding a water filled container under it) and half a glass disappeared when the pump came on! I haven't had a chance to do the other check yet as it's a bit more involved, but the nice clean water that was in the tank when I refilled last week is now a dirty brown indicating that some water from the system is getting back into the F&E tank.
When the CH is on, the air in the system does accumulate in the towel rail in the bathroom.
The boiler is a wall mounted Baxi Solo 50/4 RS, pump is a Grundfos 5M (set to 2 at the moment) feeding 8 rads and a HW cylinder and from what I can see the order is: boiler, open-vent, pump, cold feed, diverter (which conflicts with what Fernox suggest). The boiler is in the dining room (was the old kitchen) with the pump and diverter just above it under a trap-door in the floor boards in the bedroom above.
Question is, is the sucking of air through the vent-pipe ONLY associated with 'see-sawing'? If I put things in the correct order suggested by Fernox (boiler, open vent, cold feed, pump) will this problem disappear so I can get on with my life!?
