Hi there, we recently needed to change a washer on one of our hot taps and this has caused a major problem! We have an old house with a gravity fed hot water system. We shut off the main water supply to the house but couldn't find a tap or anything at the hot water cylinder so just switched it off and turned on on all the other hot water taps while we changed the washer and the hot water eventually stopped running out so thought the tank must be empty. When we turned the mains water back on we could hear the tank begin to fill but no water has come out of our hot taps again and it has been about 12 hours later! What can we do? The tank feels warm and there doesn't seem to be any leaks. Thanks!

One of our plumbing experts will be along in a bit. We volunteer here so please be patient.

As far as your problem goes it sounds like you have the system air locked. Are all the faucets still open? If so then that could be part of the problem. In a gravity system you would want to open the lowest point and allow the system to fill from there. Bleeding all the air out that is in the system

If you try to do it all at once then you won't get the syphoning effect that you need to run the water through the pipes.

Thank you for replying. I had turned all the faucets off and just checked them routinely. I have now turned on the tub tap (lowest to the ground and furtherst from the tank I think) and a small amount of cold water ran out and then stopped again. I have left it on. Is there anything else I could try? Thank you.

Where does your water come from (source) for the hot water feed and where is your hot water tank located in all of this?

I'm not sure where my hot water comes from. I have a tank on the roof (exterior) that feeds into the main hot water tank in a cupboard about 1m off the ground. All the water services Kitchen, bathroom etc) are on the opposite side of the house so the water must flow down to them if that makes sense? Its an old villa but the bathroom/kitchen was put in around 1960. Does that help at all?


Where does your water come from (source) for the hot water feed and where is your hot water tank located in all of this?

Is there a bleed valve on your hot water heater ?

Are you sure it is full ?

Hi again, problem solved. Yes it was air locked. We used a plastic tube to shoot water from the cold tap up the hot tap into the tank and it unblocked it.
Very glad to have hot water again :)

Is there a bleed valve on your hot water heater ?

Are you sure it is full ?

Thanks for the update. Always nice to hear back. Regards, Tom