dual header tank overfilling and overflowing

[dave2020]

hi
new to this forum and i have had a read on the various topics but still thought i would ask

in the airing cupboard we have a header tank above the hot water heater tank(big copper tank).

the header tank looks like its got an inner tank built in,both have separate mains water feeds thru their own ballcocks.

now the problem is that the larger of the 2 tanks is leaking thru the overflow outside,its more than a drip,more like a slow trickle.

i have tied the ballcock up on the large tank and the small tank and you can still see the water rising,takes about 5 mins to raise 5mm or so,i emptied the main tank half way down and i cannot see any water leaking from the ballcock/washer area and running down the tank side on the large tank,i cannot get into the inner header tank one to check as the space is very confined and i cant get my head all the way in as its near the roof in the airing cupboard,i suspect i will have to dismantle the whole tank to remove it to check.

now all this is happening without any of the heating turned on,we have radiators fitted but never use them,we just use the gas fire as house is usually warm enough,so we only ever have the hot water on,as i said,this is happening without any heating on.

now could it be the back ballcock in the small tank is leaking somehow and filling the main tank up?

the house is an ex council house and has all the original plumbing in etc.

thanks
dave

 

[seco services]

does it stop if you isolate the mains to the house ?

 

[dave2020]

hi
well..we turned the mains stop tap under the sink and it doesnt fully close the water off,if you turn the cold tap on downstairs it dribbles even with the stop tap under the sink turned off,however,with the stop tap in its best closed position the tank doesnt overflow,when the stop is open it does overflow.

also the mains feed to the tank in the airing cupboard has a stoptap on it but you guessed it..it doesnt work,im going to put a new one of those on this afternoon,hopefully by leaving the tap open downstairs and the stoptap in its best closed position it should be easy? (i already bought a new tap same as old one)

cheers
dave

 

[seco services]

as you say in its best closed position it stops it overflowing.

if you have any mixer taps that are hot gravity and mains cold its passing cold mains to the hot gravity apart from your kitchen mixer is their any other mixers in the house ?

one of them is faulty.

 

[dave2020]

no just the kitchen mixer tap and its brand new.

so,to check if the mixer tap is the problem im guessing i would have to have the mains tap under the sink turned on but isolate the mains water to the ballcoks in the header tanks?

are you saying that the cold water is coming in thru the mains,then the valve in the mixer tap is letting cold water to enter into the hot pipe where it enters the mixer tap,travel back up thru the piping the wrong way and backfill the header tank?

im not that upto speed on plumbing(mechanic by profession) but im a swift learner so any help appreciated.

 

[seco services]

are you saying that the cold water is coming in thru the mains,then the valve in the mixer tap is letting cold water to enter into the hot pipe where it enters the mixer tap,travel back up thru the piping the wrong way and backfill the header tank?
.

yes.

can you turn the mains stopcock back on and shut the hot side to the tap ?
is their any isolation valves to the tap under sink.

have you a shower mixer valve ? fed from gravity hot mains cold ?

 

[dave2020]

no there are no isolation valves to the taps under the sink only the mains fed stop tap..should i fit some?

we have an electric shower fitted that is mains fed upstairs,also a washing machine which is fed from both hot and cold downstairs.

could it be the washing machine also doing the same as the mixer tap?

 

[seco services]

no there are no isolation valves to the taps under the sink only the mains fed stop tap..should i fit some?

yes

could it be the washing machine also doing the same as the mixer tap?

try it for how long it takes to disconnect but i wouldn't say so.

 

[dave2020]

ok thanks

i managed to get the stop tap that feeds water to the ballcocks working in the airing cupboard,so mains is on downstairs and the ballcocks are isolated,so if it continues to overflow then it has to be a hot/cold transfer leak somewhere im guessing.

i guess i would have empty the tanks completely,isolate or lift ballcocks to a closed position and watch to see if i can see where water is entering the header tanks,there are 2 big pipes which enter the header tanks lower down,one goes to bottom of hot water cistern,other goes to mid height in same place,i guess thats where the water would backfill from?


cheers
dave

 

[seco services]

i managed to get the stop tap that feeds water to the b*****s working in the airing cupboard,so mains is on downstairs and the b*****s are isolated,so if it continues to overflow then it has to be a hot/cold transfer leak somewhere im guessing.

yes.

i guess i would have empty the tanks completely,isolate or lift b*****s to a closed position and watch to see if i can see where water is entering the header tanks,there are 2 big pipes which enter the header tanks lower down,one goes to bottom of hot water cistern,other goes to mid height in same place,i guess thats where the water would backfill from?


cheers

the water will come in one of those pipes in the bottom of tank.

you say you have two pipes entering the bottom of the tank.
one will be the feed to the cylinder.
wheres the other go ? is it bathroom cold feed or a shower ?

 

[dave2020]

no,the hot water heating tank has 2 big pipes that come off it,one goes to the bottom of the main header tank about 2 inches from bottom,the other goes what looks like into the small header tank,this pipe has a T junction on it which then goes thru under the floorboards.there are also 2 what look like 'vent' pipe which hang over the header tanks.

would a drawing be easier?

with the stoptap in the airing cupboard closed and balcocks isolated and the mains tap downstairs open the tank continued to overfill,i turned the feed off to the shower also and made no difference.
dave

 

[seco services]

drawing if you have one.

 

[dave2020]

ok here goes

the pipes as you can see go down under the floorboards so no idea where they go sorry
the hot water tank works off a back boiler behind the fire if that helps.

i took some pictures of the offending items,excuse the mess in the airing cupboard,it only gets used to store crap in there hehe.

 

[seco services]

looks like gravity hw pumped heating.

green flow
red return
grey vent and hw to taps
other red cylinder feed

yes i would still opt for the mixer tap passing. so cold mains returnig up the right hand red pipe to cold water storage

 

[giblets]

If you tie up both ball valves does the water in the small tank fall whilst the water in the large tank rises?

If so then the hot water cylinder coil has failed.