hot water coming into loft tank from immersion tank


P

Patb

After replacing the ball valve, thinking that was leaking and causing
the overflow to go, I have just realised that warm water is coming up
from the immersion in the bedroom up into the loft tank.
Grateful for advice on what I should do to stop this,
thanks
 
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J

John Rumm

Patb said:
After replacing the ball valve, thinking that was leaking and causing
the overflow to go, I have just realised that warm water is coming up
from the immersion in the bedroom up into the loft tank.
Grateful for advice on what I should do to stop this,
Could do with a little more information to answer this...

How is the hot cylinder heated - just the immersion, or is it also
heated by the central heating?

If so, what type of central heating system; vented (i.e. with a little
header tank in the loft) or sealed (no tank, but a pressure gauge and
filling loop)?

How is the warm water getting into the cold tank? Via the feed pipe that
goes from the cold tank to the base of the cylinder, or via the vent
pipe that discharges over it?
 
H

Heliotrope Smith

Patb said:
After replacing the ball valve, thinking that was leaking and causing
the overflow to go, I have just realised that warm water is coming up
from the immersion in the bedroom up into the loft tank.
Grateful for advice on what I should do to stop this,
thanks
If the cylinder is heated indirectly from your boiler then it is most likely
that the primary water coil is perforated.
Only option is to replace the cylinder.
 
P

Patb

If the cylinder is heated indirectly from your boiler then it is most likely
that the primary water coil is perforated.
Only option is to replace the cylinder.
OK, not an expert but....

the water can be heated by either the immersion of the Gas boiler.
The central heating system is vented.
Re the water getting into the tank, not sure about this. It is coming
in from a large pipe that connects to the tank in the loft via the
side of the tank at the bottom. Do I have to track this pipe to see
where it connects to the immersion?
Thanks for the feedback so far
 
J

John Rumm

Patb said:
OK, not an expert but....

the water can be heated by either the immersion of the Gas boiler.
The central heating system is vented.
Re the water getting into the tank, not sure about this. It is coming
in from a large pipe that connects to the tank in the loft via the
side of the tank at the bottom. Do I have to track this pipe to see
where it connects to the immersion?
No, if it is coming into the base of the cold tank, then that is almost
certainly the feed out to the hot cylinder.

Options would seem to be, primary heating water escaping from the the
heat exchanger coil in the cylinder. Check the relative heads of the
cold tank and heating header tank. Is it possible for the water level in
the header to be higher than in the cold tank? If it looks possible that
this is happening then a new cylinder would be the cure.

Another option would be if you have any mixer taps that have a mains
cold feed to one side, and the tap is "letting by" - forcing mains cold
water back up the hot pipe. Can be particularly noticeable if you have a
mixer like this that has a shower on it. (you should not use true mixer
taps in these situations unless you have non return valves also fitted)
 
M

m_sbuilders

It'll be the primary coil.......I had the same problem......did my
head in trying to find out the cause.....I replaced the washer. the
valve etc. When I came to replace the cylinder I found a barsteward
thread and had to abort the swap.ggrrhhhhh
 
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H

Heliotrope Smith

Patb said:
OK, not an expert but....

the water can be heated by either the immersion of the Gas boiler.
The central heating system is vented.
Re the water getting into the tank, not sure about this. It is coming
in from a large pipe that connects to the tank in the loft via the
side of the tank at the bottom. Do I have to track this pipe to see
where it connects to the immersion?
Thanks for the feedback so far
When you trace that pipe back I am sure you will find it goes down to the
bottom of the cylinder (immersion as you call it).
That is the cold feed to the cylinder.

Have a look inside the SMALL tank in the loft (the boiler header tank).
Is this continually dripping but not overflowing?
 
P

Patb

replacing the ball valve, thinking that was leaking and causing






When you trace that pipe back I am sure you will find it goes down to the
bottom of the cylinder (immersion as you call it).
That is the cold feed to the cylinder.

Have a look inside the SMALL tank in theloft(the boiler header tank).
Is this continually dripping but not overflowing?- Hide quoted text -

- Show quoted text -
Thanks for all the feeabck so far.

The latest in the saga is that the tank in the lost went into overflow
mode last night even though neither the gas boiler or the immersion
was on. So cold water is coming into the loft tank. I had assumed that
it was only hot water that would come up due to convection.
Is there any problem with draining the large tank right down so I can
actually see the water coming in?

Heliotrope, I will look in the small loft tank and report back (why is
life so complicated? Still don't realy understand why we need to have
tanks of cold water sitting in the lost in the first plalce)
 
P

Patb

Thanks for all the feeabck so far.

The latest in the saga is that the tank in the lost went into overflow
mode last night even though neither the gas boiler or the immersion
was on. So cold water is coming into thelofttank. I had assumed that
it was only hot water that would come up due to convection.
Is there any problem with draining the large tank right down so I can
actually see the water coming in?

Heliotrope, I will look in the smalllofttank and report back (why is
life so complicated? Still don't realy understand why we need to have
tanks of cold water sitting in the lost in the first plalce)- Hide quoted text -

- Show quoted text -
Been a busy afternoon. I drained down the lost tak and then could
actually see the cold ater tricling up from the immersion into the
tank. Based on John's advice, I went aroud and isolted the three mixer
taps, this made no difference. So the prime suspect must be the shower
which does have a mixer unit on. Not sure how to isolate this other
than turning ff the mains. I took the shower off the wall and both the
hot and cold pipes have what look to be small non-return valves built
in. Took these out and put them back in, ensuring that they seemd to
operate smoothly, replaced shower unit. If I wake up tomorrow, with no
overflow dripping... BINGO!! If not, any ideas?
 
H

Heliotrope Smith

Patb said:
Thanks for all the feeabck so far.

The latest in the saga is that the tank in the lost went into overflow
mode last night even though neither the gas boiler or the immersion
was on. So cold water is coming into the loft tank. I had assumed that
it was only hot water that would come up due to convection.
Is there any problem with draining the large tank right down so I can
actually see the water coming in?

Heliotrope, I will look in the small loft tank and report back (why is
life so complicated? Still don't realy understand why we need to have
tanks of cold water sitting in the lost in the first plalce)
..
I am afraid it looks more and more likely that the coil inside the cylinder
is holed.
It makes no difference if either the boiler or the immersion heater are on
or not.
It would seem that the small tank is higher than the large tank. The small
tank contains the water that is inside the coil in the cylinder, so if the
water can get out it must try to find the same level as that it started at.
 
B

Bob Minchin

John said:
Could do with a little more information to answer this...

How is the hot cylinder heated - just the immersion, or is it also
heated by the central heating?

If so, what type of central heating system; vented (i.e. with a little
header tank in the loft) or sealed (no tank, but a pressure gauge and
filling loop)?

How is the warm water getting into the cold tank? Via the feed pipe that
goes from the cold tank to the base of the cylinder, or via the vent
pipe that discharges over it?
The usual problem is a leak between the primary and secondary hot water
circuits. A new cylinder is likely to be needed.

Bob
 
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J

John Rumm

Patb said:
overflow dripping... BINGO!! If not, any ideas?
Make sure the heating and immersion are off. Get a rubber bung (or in
extremis a carrot!) and reach into the small header tank and plug the
outlet. Drain some water from the main tank, and see if it is still
refilling. If not, and removing the bung from the header tank starts it
filling again, then you have a leak in your cylinder's heat exchanger coil.
 
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P

Patb

The usual problem is a leak between the primary and secondary hot water
circuits. A new cylinder is likely to be needed.

Bob- Hide quoted text -

- Show quoted text -
OK, I drained down the tank in the loft to confirm that water is
coming up from the immersion. Sure enough, there was a steady trickle.
I also checked the smaller boiler header tank. This looks rock solid,
nowhere near over flowing.
We recently had an extension put in with 3 new mixer taps and a
shower. I isolated each mixer to see if this stopped the trickle, non
did. Could not see how to isolate the shower but took the mixer part
off the wall. There seemed to be a small non-return valve built into
the inlet on both hot and cold. I tickered with them to ensure they
could move in and out smoothly and then re-installed it. Fingers
crossed that it was the shower unit "letting by". Monitoring the water
level in the loft tank today
thanks for all the advice, I will let you know
 

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