Hot water taps, nothing.

[markmm]

Hi folks,

I would appreciate any help with my plumbing plight. I live in a top floor 100 year old flat that has high ceilings. The mains feeds the kitchen sink cold tap, the washing machine cold tap and the boiler. The only other outlets are in the bathroom (sink and bath taps and shower) the cold in those taps comes from a big tank in the ceiling (low pressure). The central heating is gas heated and works ok.

There is also a really small tank next to the big tank with a ballcock which has a open pipe hovering over it. It is not full. Then there is a big cyclinder in the cuboard near the tanks that I think feeds all the hot water taps.

The problem is that there is no water coming from any of the hot water taps, all the cold taps and central heating is working. This has happened 3 or 4 times in the last 7 months and usually I got a plumber out and he fiddled with it to get it working saying it was an airlock caused by the hot water over boiling??.

I have a mixer tap in the kitchen and tried putting my thumb over that while opening both to unlock the hot but it doesn't seem to work. Don't know if I should have the bathroom hot taps open while doing this? And how long should I do it for? Is there any other way to unblock, by emptying the system say?


Thanks

Mark

 

[kevplumb]

join the hot and cold washing machine taps with one of the hoses and open the valves slowly

 

[markmm]

join the hot and cold washing machine taps with one of the hoses and open the valves slowly

Thanks Kev,

The washing machine only has a cold pipe and a waste though.

Mark

 

[kevplumb]

ok you need to link cold main tap to hot tap

and do the same

you have a mixer in the kitchen

get a cloth or rubber glove and put it over the end of the spout with the hot turned on then open the cold

not your thumb use your palm

 

[Burnerman]

The large tank in the loft is the header tank, that keeps the copper cylinder full of water. This tank is kept full by its float valve (ball cock). The smaller tank is the central heating flow and expansion tank that usually has about 4" of water in it, and that is of no concern at the moment.
Your system is airlocked, and as Kev says, connecting high pressure cold water from the mains into the hot water system forces water back up to the loft tank, hopefully clearing the air bubble as it does so. If your washing machine has a hot and cold supply, then a pipe connecting the two is ideal. Your idea with the mixer tap can achieve exactly the same thing, but you can get wet!
If your hot water is getting so hot as to form an air bubble, maybe your boiler thermostat is faulty?
John

 

[Burnerman]

Didn't mean to poach, Kev
John

 

[kevplumb]

err we are assuming you have checked the tanks first

 

[kevplumb]

Didn't mean to poach, Kev
John

dive in fella

 

[markmm]

There is cold water flowing from the cold taps which is fed from the cold header tank, so that must be ok. How do I check the hot water tank?, it looks sealed.

 

[kevplumb]

na if there is cold water flowing from the tank to taps then its ok

 

[markmm]

na if there is cold water flowing from the tank to taps then its ok

I checked the hot tank, there is 4 pipes attached. One at bottom, one at top then one just above middle and one below the middle. The one above the middle is hot for about a foot then is cold, is this the airlock?

 

[markmm]

Ok tried the palm with rubber glove over the mixer tap and it seemed to work, the water started running hot, for about 2-3 mins then trickled to nothing. I repeated it a few times but the same result. Does this still sound like an airlock?

 

[kevplumb]

hold your hand over a bit longer

 

[markmm]

hold your hand over a bit longer

I don't get it, so when I am doing this the cold water is running back up the hot water pipe, this pipe I assume joins all the other hot water pipes and then goes into the HW tank? So why is working for a few mins? Surely the air lock is gone to allow HW to come out? Then a new airlock must be appearing?

Sorry Just trying to understand.

 

[kevplumb]

View media item 16806
ok if you ignore the heating bit

just the cylinder and header tank

it might make sense to you