Hi all,
I have just replaced an expansion vessel which is connected to the feed of an unvented hot water cylinder. The old one was completely full of water and not functioning. The new one is doing much better and sounds hollow at the top and water filled at the bottom - so that is all good news. There is a question of pressure though. The mains feed is above 3 bar and i have a reducer with a gauge which brings the supply down to 3 bar. The pressure on the top of the expansion vessel is 2.6 bar (with the water on). There is something in the vessel instructions about setting the pressure to 1/2 bar more or less than something else, but it is too technical for me to interpret. Can anybody advise what the vessel pressure should be for a 3 bar supply on a 210 litre tank. I can drain down easily enough or fill from cold if the pressure setting should be prior to pressurising if that is what is required. Thanks for your help.
[BTW - an auxilary question which comes to mind - when i bought the new vessel i could hear the rubber bag flopping around inside. I phoned the manufacturer and asked if this was normal and they said that it was. The pre-install pressure is 3 bar according to the leaflet. Sureley if there is 3 bar (45+ psi) of pressure in there the bag should be pinned down to the bottom not flopping around! Or does it only become 3 bar once the vessel fills with water to a certain point. This would make more sense as the air void would become much smaller and the pressure would increase proportianally to the reduction in volume. Just interested really.]
Thanks,
Don
I have just replaced an expansion vessel which is connected to the feed of an unvented hot water cylinder. The old one was completely full of water and not functioning. The new one is doing much better and sounds hollow at the top and water filled at the bottom - so that is all good news. There is a question of pressure though. The mains feed is above 3 bar and i have a reducer with a gauge which brings the supply down to 3 bar. The pressure on the top of the expansion vessel is 2.6 bar (with the water on). There is something in the vessel instructions about setting the pressure to 1/2 bar more or less than something else, but it is too technical for me to interpret. Can anybody advise what the vessel pressure should be for a 3 bar supply on a 210 litre tank. I can drain down easily enough or fill from cold if the pressure setting should be prior to pressurising if that is what is required. Thanks for your help.
[BTW - an auxilary question which comes to mind - when i bought the new vessel i could hear the rubber bag flopping around inside. I phoned the manufacturer and asked if this was normal and they said that it was. The pre-install pressure is 3 bar according to the leaflet. Sureley if there is 3 bar (45+ psi) of pressure in there the bag should be pinned down to the bottom not flopping around! Or does it only become 3 bar once the vessel fills with water to a certain point. This would make more sense as the air void would become much smaller and the pressure would increase proportianally to the reduction in volume. Just interested really.]
Thanks,
Don
