Empty hot water tank - airlock? Please Help...

[Tim H]

Today I successfully managed to replace the siphon in my toilet. To do this I had to turn off the water supply to the flat (obviously) and then needed to drain the two large interconnnected water tanks in our attic space by running the taps until they were dry - since these water tanks feed the loo…

After finishing the siphon job I reconnected the water supply and waited for the two attic waters tanks to refill. The cold water taps and the loo all work beautifully however when I turned on the hot taps the pressure seemed very low and the hot water just tricked out. Looking at the plumbing configuration in the attic it appears (I think) that one of the two water tanks feeds my emersion / hot water tank by gravity. This involve a copper pipe wipe comes out of the TOP of the tank and then doubles back on it self before going down to hot water tank.

I imagine that by draining the water tanks in the attic the ‘petrol siphon’ effect that fed the hot water tank could no longer work. What I need to know is how to perform the equivalent of a ‘petrol siphon suck’. i.e. I need to know how to reprime my hot water tank. Anyone any ideas – please help or its no washing for me till Monday…

 

[chrishutt]

You've got an air lock in your hot water supply pipework. Do a search for advice on how to clear this.

Why on earth did you drain the feed tanks? You could have just turned off the gatevalve on the supply pipe from the tank. Also you are quite wrong about the "syphon" effect with the vent pipe than inverts over the tank. This should not dip into the water (or be anywhere near the water level).

 

[Tim H]

Cheers Chris, I did look for an isolator valve from the feed tank at the time and there was one for the bath tap and sink tap but it did not appear to be for feed for the loo. I've just checked this and indeed it does stop the toilets supply so I could have saved myself a lot of trouble!

I'll do the search you suggest to try to reprime / remove the air lock from the hot water...

Cheers.

 

[Tim H]

Fixed the air lock...

By turning on both the cold and hot taps on my bath's mixer tap it obviously formed a vacuum and pulled it through - at least I think thats what happened...