L
letsfixitnow
:annoyed:I am getting recurring airlocks in our ho****er pipes and have to clear the air lock daily, usually in the evening when the water is getting hot. I have a low pressure HW cylinder gravity fed by a 60Litre supply tank in the roof space. The HW cylinder is heated by a wetback from a woodburner stove (Rayburn). The wetback water is separate from the water in the HW cylinder, and both are separately vented. At the top of the HW cylinder about 12in up from the top the 3/4inch exit vent pipe does a sharp right turn and runs horizontal then slightly upwards for about 6metres then turns vertical and goes up thru the roof and ends up outside about 1.5m above the roof. It seems to work very well except when we sometimes heat the water from our Rayburn. The problem seems to occur in the evening after the fire has been going for a few hours and the water starts to get very hot. I can sometimes hear the water gurgling in the HW cylinder and I assume that bubbles of air are being created in the cylinder but not venting out. When I open a hot tap then air bubbles are in the stream but initially don't create a problem. However it gets to a point when an airlock is created and ends up blocking ho****er from coming out of any of the taps. I then have to clear the blockage in the usual way by running coldwater up the hotpipe and it usually clears it. I am thinking the cause could be that the air is not venting and moving up the vent pipe and outside because of the volume of water in the pipe above it. It seems to be trapped. It has 6m to travel sideways before heading upwards and out thru the top of the vent? If this could be the cause then perhaps I need to run the ventpipe vertically out the top of the HW cylinder? Then the air can vent out more directly?
