# Overflow pipe from tank in attic



## redriddick (11 Mar 2009)

Hi guys,
Have a funny one for ye.I have a dual coil cylinder in my hot press which is heated by a solid fuel stove and the oil on the other side.They also heat the radiators obviously.For the past number of weeks my overflow fron the feed tank in the attic has been dripping.I went up to look and took some water out of it and adjusted the ballcock.For two days it was fine then back to the same again.I then disconected the ballcock altogether and blanked it, took out some water and low and behold it is still at it.Cant understand how the extra water is getting into the tank to cause it to overflow.Dont think there can be a hole in the coil as the hot water from the tank is crystal clear.Any suggestions would be great!


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## DavyJones (11 Mar 2009)

You have a hole in you Cylinder coil.

You may or may not find a slight colour in your water. It really depends if the system has been treated or not.


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## redriddick (11 Mar 2009)

Hi Davy,
The system has not been treated and have to say would be very unimpressed if there is a hole in coil as it is in less than 5 years old.Any way of definitely putting it down to this?


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## DavyJones (11 Mar 2009)

redriddick said:


> .Any way of definitely putting it down to this?




Yes and you have done it.

the Feed and expansion tank is lower than the storage tank?

To confirm it, you would have to disconnect and remove cylinder. Blank flow or return and blow through it, you will feel the air escaping.

Chances are it is a pin hole.


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## redriddick (11 Mar 2009)

The feed and expansion tank is beside the storage tank so would be lower than it.Will i have to change the cylinder or is there any other fix?


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## DavyJones (11 Mar 2009)

Maybe the reason why the water is not stained. Fresh water entering heating system as opposed to heating water entering plumbing water, this would happen  if F&E tank were higher than storage tank, possibly.

No fix (that I know of) other than replace.


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## kingfo (11 Mar 2009)

Maybe both pumps on at once and pitching back into tank, could overflow for a while.


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## DavyJones (11 Mar 2009)

Possible but highly unlikely for two reasons.

redriddick, stated it was dripping over a number of weeks. I would take that it was constant.

More importantly he removed water from the tank and blanked ballcock. This is all the water that the system can get,I.E tank is not being refilled. Even if it was pitching, it would very soon run out of water to overflow as the water in the tank would be refilling system as it pitched. he would in a short time find the tank low in water or even empty.


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## redriddick (12 Mar 2009)

Hi Guys,

I have decided to turn off heat on saturday while im at home to see if it is dripping when the heat is off.This will confirm the pin hole.Priced cylinder and it is €450 plus vat will be fitting it myself as it was me that plumbed the house.Thanks guys.


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## SISSOKO (17 Mar 2009)

Hi guys,think i might have a similar problem.over the last couple of months the tank would over flow every couple of days could have been every day
but might not have noticed.It was overflowing alot this morning when i got
up so decided to go up and have a look at tank.
Ballcock seemed to be working fine and no water coming in there , but
the water itself seemed quite warm for a cold water storage tank , any ideas what my problem is ?.I have oil fired central heating UFH downstairs
and rads upstairs.


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## DavyJones (17 Mar 2009)

redriddick said:


> Hi Guys,
> 
> I have decided to turn off heat on saturday while im at home to see if it is dripping when the heat is off.This will confirm the pin hole.Priced cylinder and it is €450 plus vat will be fitting it myself as it was me that plumbed the house.Thanks guys.




Any news on that?



SISSOKO said:


> Hi guys,think i might have a similar problem.over the last couple of months the tank would over flow every couple of days could have been every day
> but might not have noticed.It was overflowing alot this morning when i got
> up so decided to go up and have a look at tank.
> Ballcock seemed to be working fine and no water coming in there , but
> ...




Do what redriddrick did to confirm or discount hole in cylinder.

Is it the big or small tank that is overflowing?


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## redriddick (17 Mar 2009)

Hi Davy,

As we thought it is the cylinder coil.Had heat off and it was still at it.What do you think of the price of the cylinder.Dual coil 18" x 60" 36" element and fully insulated 450 plus vat.Have to say just about 4 and half years in would'nt like this every 4 years or so.Thanks.


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## DavyJones (17 Mar 2009)

redriddick said:


> Hi Davy,
> 
> As we thought it is the cylinder coil.Had heat off and it was still at it.What do you think of the price of the cylinder.Dual coil 18" x 60" 36" element and fully insulated 450 plus vat.Have to say just about 4 and half years in would'nt like this every 4 years or so.Thanks.




Can't remember of top of my head., but trade price on those items would be about €400-ish. Not a bad price.Ask/insist on best price.

besure and treat heating system after installation.


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## redriddick (17 Mar 2009)

Will treat it alright.Still cant get over that it is gone already but i guess you can always get faulty ones.Thanks for the help Davy!


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## SISSOKO (17 Mar 2009)

DavyJones , just come home now after been out for a fw hours water is
p**sing out over flow was at it when i left so presume its been like that since.
have 2 tanks in attic that are the same size that are connedted at the base of each,should there be a small & big tank ??
boiler hasnt been on since 8am this morning.
didnt adjust ballcock earlier.
Will do that tomorrow and see what happens.


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## BD plumbing (19 Mar 2009)

if the tanks are joined then you have a sealed heating system i.e. the heating water will not mix with the domestic water unless there is a hole in the coil but i doubht it if its only 5 years old more then likely the stat is knackered in the emersion or in the boiler and is boiling the water in the cylinder and as water expands when its boiling due to the conversion into gas it needs to expand up the expansion pipe hence the name  make sure the emmersion is not on and also check if the water is coming out of the pipe hovering above the tank in the attic and if you have 2 pipes hovering over the tank indicate which on is pitching and if its from the cylinder then its more then likely the emmersion but if its pitching from the heating expansion well then there could be a blockadge or the pump setting could be to high hope this helps


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## SISSOKO (20 Mar 2009)

BD , we rarely use emersion to heat the water so dont think its overheating , stat on boiler seems ok too so no overheating there , one expansion pipe hovering over tank in attic and no water coming out that to fill and over flow storage tank , ballcock working fine so no excess water coming in there.
Am i right in saying that the only other cause is the one Davyjones indentified , hole
in coil in hot water cylinder ?? and have to replace ??


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## DavyJones (20 Mar 2009)

SISSOKO said:


> BD , we rarely use emersion to heat the water so dont think its overheating , stat on boiler seems ok too so no overheating there , one expansion pipe hovering over tank in attic and no water coming out that to fill and over flow storage tank , ballcock working fine so no excess water coming in there.
> Am i right in saying that the only other cause is the one Davyjones indentified , hole
> in coil in hot water cylinder ?? and have to replace ??




Firstly we need to establish how your heating system is topped up with water.

It may be a "semi sealed" system, this is an Irish way of doing something that breaks a whole lot of by laws (story for another day).

Semi sealed is where the heating water is taken from the same source as the plumbing water I.E your two large tanks. If this is the case then you probably don't have a hole in the cylinder, as in a hole in the cylinder would not cause the tanks to over flow as the system water (heating and plumbing) would balance without a need to rise.

However if you have a set automatic filling unit filling your heating it will automatically fill when water leaves heating system. this could cause the tank to over flow and would mean you have a hole.

So, do you have a gauge at the boiler?
Do you have a big brass valve somewhere with a gauge and black knob attached?

Do you have a sliver fexlible hose connecting to pipes together in hot press or at boiler(there is valves with normally black handles)?

It is likely it is the ballcock, keep an eye on it.


I know it's alot of information and if you feel I could explain it better please ask.


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## SISSOKO (20 Mar 2009)

DavyJones said:


> Firstly we need to establish how your heating system is topped up with water.
> 
> It may be a "semi sealed" system, this is an Irish way of doing something that breaks a whole lot of by laws (story for another day).
> 
> ...


 
Davyjones , no gauge at boiler , brass valve to rear of cylinder with guage
going up to 4 bar with red and black needles.Red needle seems to be constant at 2 bar , black just above zero.Thought that black needle used to move when heating was on but could be mistaken.
No sign of any silver flexi hose anywhere that i can see , as bad as ever this evening.


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## DavyJones (20 Mar 2009)

SISSOKO said:


> Davyjones , no gauge at boiler , brass valve to rear of cylinder with guage
> going up to 4 bar with red and black needles.Red needle seems to be constant at 2 bar , black just above zero.Thought that black needle used to move when heating was on but could be mistaken.
> No sign of any silver flexi hose anywhere that i can see , as bad as ever this evening.




Ok, that could be an automatic filling valve. Is there a black wheel type handle.

If so close it. Rightly tighty, lefty loosely!


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## SISSOKO (20 Mar 2009)

OK closed that , only took about half a turn and its not so much a wheel type
but more of a knob type what should i expect


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## DavyJones (20 Mar 2009)

Not a lot I would think.

Unlikey to be hole in cylinder.
Are the tanks still overflowing?
Have you checked the ballcock in tanks again, this is the most probable cause.


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## SISSOKO (20 Mar 2009)

ok ,went up and had a look at tanks , pipe from right hand base of cylinder that goes up into attic and is connected to both tanks at base of each is warm all the way up and you can actually see the waves of tha warm water entering tanks.Ballcock not letting in water and tank is about to overflow. What the hell is causing that ?? frustrated now!!


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## DavyJones (20 Mar 2009)

ok.
You have hot water expanding back through the cold fed to cylinder?

At the moment you have heating on?

Off the top of the cylinder there is a hot draw off pipe and an expansion pipe that hooks over top of tanks, ensure this is not obstructed or blocked.

As mentioned earlier it may be a faulty immersion. you should use a phase tester to prove that no power is going to immersion when switch is off. The fault would be at the switch, theromstat fault at immersion.


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## SISSOKO (20 Mar 2009)

Heating off since 8pm , cant see any obstruction to expansion pipe , pipe from top of cylinder to expansion pipe is cold , will check immersion to seeif its on constantly but
that would mean we have constant hot water but we dont.........if its not the immersion have we exhausted the possible causes?


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## DavyJones (22 Mar 2009)

How is it today?

You have isolated water entering the heating system? By way of shutting off auto filling valve.

Does it still overflow once heating is off?


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## SISSOKO (22 Mar 2009)

Hi Davyjones , Shut off valve as you said , still overflowing and no heat or 
immersion on today , had a look about an hour ago and  problem
is definately water coming back up the feed pipe from cylinder to storage tank when it should be going the other way as needed. 

That would suggest pressure causing it to rise am i correct?
So does that mean hole in coil ?


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## DavyJones (23 Mar 2009)

We need to isolate filling valve from system to ensure it is off?

To do this shut down mains..check tank, water should now have stopped back feeding?

either blank or valve mains side of auto filling valve and turn back on water. If it stops, then you have hole in coil.


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## SISSOKO (23 Mar 2009)

Davy , update for ya , tanks overflowing this evening as usual got young fella to turn
off feed from tank to cylinder and straight away water started coming out expansion pipe.
Does this confirm hole in cylinder causing water to feed back into tank?
Also should i leave the filling valve for heating shut off?


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## DavyJones (23 Mar 2009)

Looks like the only thing it can be. The auto filling valve is letting.

Does the water stop when you turn off mains?

I don't understand your last question.


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## SISSOKO (24 Mar 2009)

Yes overflow stops when mains is turned off , should the knob on the auto filling valve be left closed tightly all the time.


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## DavyJones (24 Mar 2009)

Your best bet is too replace the auto valve for a filling loop. you could also fit a gauge nearby to allow you to observe pressure drop.


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## SISSOKO (19 May 2009)

Problem solved , while in the process of replacing cylinder plumber noticed water flowing back into cylinder from pipe that feeds hot taps while cylinder completely
disconnected.
Turns out mains pressure was crossing over mixer taps forcing water back up into
cylinder and up to tank through cold water feed and causing tank to overflow.

Fitted non return valves to taps to stop this , seems to have worked o.k.


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