How can I prove cylinder coil leak?

[omits]

I've turned off the cold feed to the HW tank but sort of gurgles then builds up a bit then dribbles. Have I got a coil leaking into the main part?

 

[denso13]

cold feed to the HW tank

Do you mean, the HW cylinder or the cistern in the loft? Are there there two cisterns in the loft, one small, one large?

 

[omits]

Do you mean, the HW cylinder or the cistern in the loft? Are there there two cisterns in the loft, one small, one large?

HW Cylinder. Thanks. Thinking about this as the CW tank in the loft is on the same platform as the small CH filling tank then if there was a leak in the HW cylinder coil this small tank would overflow due to the water level in it being far lower thn the CW tank next to it. Am I right?

 

[ianmcd]

If you have a thermostatic mixer shower or tap, I would be looking there first, coil pinholing can happen but is very rare , turn off the cold feed to the Cylinder, then open the mixer (shower or tap) and set to max Hot and if it keeps dribbling then you have what is called crossover

 

[Deleted member 294929]

HW Cylinder. Thanks. Thinking about this as the CW tank in the loft is on the same platform as the small CH filling tank then if there was a leak in the HW cylinder coil this small tank would overflow due to the water level in it being far lower thn the CW tank next to it. Am I right?

Yes I had one the other week

 

[denso13]

Am I right?

Yes, that's correct.