Hot Water Cylinder Not Filling Properly - URGENT HELP PLEASE

[Tuafan]

Hi there,

we have a low pressure hot water system - header tank in ceiling, and a 180litre main cylinder. It is a very old cylinder, and is now leaking slightly from the bottom.

In my attempts to temporarily fix the leak, we turned off the tap from the header tank to the main cylinder, and emptied the cylinder. We have now turned the tap on the header tank back on - but the cylinder is only filling with a few litres - maybe only about 30 at most? Subsequently it is near impossible to have a shower, etc because there is very limited hot water pressure. I turned the mains power to the cylinder off, as I am worried it may burn out with not enough water in it.

Did we do the refilling wrong? Do we need to do this over again, have the house taps all on when we turn the header tank tap on, or do we need to have them off? Is there something else we need to do that we haven't done?

Thanks heaps - any basic advice (novice DIY person here!) would be great thanks. We really need to get this fixed ASAP as the children and my Wife arn't to happy about no showers!


Thanks again,

Trevor

 

[kirkgas]

could be a couple of things, airlock, or blockage in pipe to tank, or tank not refilling, check tank in loft to see if it full, then it could be an airlock when refilling, shut the valve feeding the cylinder again, then start to drain it down again, while draining reopen the valve and you might pull the airlock thro the tank, if so you should hear it refilling again, leave a tap open to allow the sir and water to come out when refilled,

 

[Reg Man]

Sounds like you could have an air lock. At worst it could be a limescale issue. Temporary fix to leaking hot water vessels are not mormaly sucessful on the longer term. Look at replacing the vessel.

 

[REDSAW]

you didnt break the gate valve when you turned it of did you (free turning).
open hot, hold up ball cock and see rate it is filling by monitoring water level in header.
back fill system will clear scale and air locks.

 

[Reg Man]

Yer good point, could have sheared the gate valve spindle and dropped the gate.

 

[Tuafan]

Sounds like you could have an air lock. At worst it could be a limescale issue. Temporary fix to leaking hot water vessels are not normaly sucessful on the longer term. Look at replacing the vessel.

Yes we will be getting a new cylinder asap. Thanks.

 

[Tuafan]

you didnt break the gate valve when you turned it of did you (free turning).
open hot, hold up ball cock and see rate it is filling by monitoring water level in header.
back fill system will clear scale and air locks.

Hi - not sure what the 'gate valve' is? It was really stiff, and we had to use leverage to turn it off, then back on again. It did start filling as soon as we got it back on.

Sorry but I'm not a 100% sure what you mean by 'back fill'?

Thanks heaps for your reply.

 

[yorkieplumber]

Hi the valve you turned the water off with sounds favourite to me, it will have snapped probably when you opened it back up, you will need to replace it, you need to block off outlet in tank, then replace valve, airlock is a possibility as well, if thats the case you will need to back fill it to remove airlock. If your not sure best thing at this point would be to call a plumber out, or you could end up causing more problems for yourself, hope this helps.

 

[Tuafan]

Thanks Yorkie.

Header tank tap still seems to work fine though. I just turned the tap back off, emptied it completely via the pipe that comes out from bottom of cylinder (that has tap on it). Kept hot water taps on for a while, and pipe tap on for a while as I turned the header tank back on, then turned them off one at a time. Header tank is filling, but now when I try the hot taps there is no water coming from them.

I'm at a complete loss now! What do I do exactly to "back fill"?

Yes - if all else fails I will have to get a plumber in tomorrow.

Thanks for all your help to date!

Trevor (in New Zealand)

Hi the valve you turned the water off with sounds favourite to me, it will have snapped probably when you opened it back up, you will need to replace it, you need to block off outlet in tank, then replace valve, airlock is a possibility as well, if thats the case you will need to back fill it to remove airlock. If your not sure best thing at this point would be to call a plumber out, or you could end up causing more problems for yourself, hope this helps.

 

[yorkieplumber]

backfill you need to force cold mains water through your hot pipewok, best way is back of washing machine so long as it is hot and cold fill, connect hot and cold washing machine valves together with one of washing machine hoses and turn both valves on for ten seconds or so, turn them off then fully open kitchen sink tap and hopefully air lock should be clear.

Steve.