cracked coil in hot water cyl?

[John.Stitch]

AGA and immersion heater heat the hot water.
AGA supplies heat via two connections at rear of HW tank
Two water tanks in loft: CWS and F/E.

The F/E overflow drips outside and the valve does not seem to leak.

The CWS valve dribbles (replaced 3 months ago) and does not shut off by water level alone, IE I can lift the ball and it will shut off.

One pipe (feed) from the AGA to the HW tank is warm but not as hot as
usual, the other (return) is cold instead of being warm

With the IH turned off the AGA does not heat the hot water in the HW tank, when the IH is used to heat water, the heat drains away.

The shower drips (hot side) and I am replacing this in the next two days with another new valve.

I seem to be replacing parts of this system which was installed 30 years ago.
One toilet
Four taps
One Immersion heater
two gate valves
One Ball valve in CWS
To do: shower valve.


If it is the coil what tests can I do?

Are there any other considerations beyond getting the same size replacement tank and to switch off the AGA and to drain the AGA water system and to also shut off and drain the cold and hot water systems?

Is the best way to drain the hot water cyl via a downstairs hot tap?

 

[adlplumbing]

not come across leaking coil yet
but in theorey and will be corrected if i am wrong
the vent pipe on etheir f & e or cws permently runs which ever is lower

 

[bellairaphon]

If it is the coil what tests can I do?

quote]

one to do which ive found to be quite good.turn your stop cock off and start draining the heating curcuit then go up into the loft and watch the water in the cws if that goes down without any taps been opened then the water is going somewhere and pointing to the cyclinder

Nath

 

[lilleville]

I have had exactly this! It sounds exactly like the coil has split. The excessive heat from the Aga created terrible limescale over time (heating hard water above 60 degs causes more limescale - the Aga heated it well in excess of that), which corroded the coil and resulted in the bv in the CWS constantly dripping and showing up from the overflow from the f&e. The fact that the heat is dispersed says it is going somewhere else! Into the cylinder!! The fact that the f&e is dripping from the overflow and the bv is ok says the water is coming from somewhere else. It has to be the CWS!

Sounds like a new cylinder to me!!

 

[John.Stitch]

It is a high Limescale area as we are adjacent to a Limestone ridge, some of which was quarried and used in Avonmouth docks, they stopped quarrying it as it was too hard.
I will replace the ball valve in the F/E tank as I have one spare and talk to the AGA engineer on Monday.
Thanks for your comments

 

[1oldspindle]

Hi John, before you go too far consider that it may be a mixer tap or shower mixer, internally passing mains water into the hot water pipe. Then pushing what should be hot out of the overflow pipe of the tank
Good luck..

 

[John.Stitch]

Hi John, before you go too far consider that it may be a mixer tap or shower mixer, internally passing mains water into the hot water pipe. Then pushing what should be hot out of the overflow pipe of the tank.

No that would not happen. There is a mixer shower due for replacement and the hot drips but not the cold, the mixer tap in the kitchen is a Franke and 2 years old and if the cold did leak into the hot, the overflow pipe into the F/E tank would drip or dribble which it wasn't.

Spoke to the AGA engineer and the symptoms I described were the same he gave me for a cracked coil and he also recommended using a 40 gallon tank instead of a 20 gallon tank, as did AGA.

So I replaced the tank with a 35 gallon one and the CWS tank valve now shuts off and the F/E tank is only half full and not overflowing.
Just got to wait to see how long it takes for the AGA to heat the hot water.
The old tank was heavier than the new due to all the scale in it.
Do they have a scrap value, price of copper etc?

 

[Hugh Jaleak]

Scrap copper is always worth something, price fluctuates wildly at times for various reasons. I believe its on the increase again at the moment. Braziery copper around the £2900/tonne mark this week, so about £2.90/kg.

I take my scrap to European Metal Recycling when I have enough to weigh in. Or I am skint. (Which seems to be permanently at moment. Teenage daughter seeing to that! )