vented direct hot water cylinder expansion problems

[Agile]

Thanks mate there are only two other mixing valves we have taken them off and blanked tails

So why was this not found before?

 

[alpina1970]

Oh sorry but we had another extension to the hot water supply that we found out about

 

[Agile]

Right, one of those extensions!

 

[alpina1970]

Its a hotel with 3 extensions 1 of which we had no access to...if thats ok with your approval

 

[Agile]

Should always have access to the whole property!

I fitted a lever valve under a bath isolating H&C to further rooms which were not yet fully plumbed.

Silly builders turned valve on for no obvious reason! They were English too!

 

[JBPHS]

What's the volume of the cylinder mate? Is there a secondary circulation pump fitted?

James.

 

[alpina1970]

Direct cylinder james..thanks

 

[JBPHS]

I'll give you a clue it's not difficult:

Volume I.e. 120 litres.

Secondary circulation (bronze or stainless steel) circulators (pumps) can still be fitted to a direct cylinder.

James.

 

[alpina1970]

Ok give me your best theory james 144l and storage is 150gallon fed with 28mm copper
No pumps fitted

 

[alpina1970]

James bear in mind were not idiots only looking initially for other possibilities that we have overlooked. ..I know what volume means

 

[stardanny]

Hooray! You found it.

Cylinder is a bit small, is it, for a small hotel? How many taps and shower mixer do it serve?

And cold water come from main?

Bear in mind that the temperature of hot water need to be at 60c to prevent legionella and blending valve at end user / thermostat control mixer at shower.

Daniel.

 

[JBPHS]

Seeing as you are not idiots, you will of course fitted a full bore isolation valve where the DHW tees from the expansion. Allowing you to close the valve, I.e. eliminating any exterior influences such as TMV's, mixer taps, mixer showers, etc.

If problem continues, isolate the ball valve. Remove some water from the CWS (10 litres should be ample).

Then come back with findings.

James.

 

[stardanny]

.......only when gate valve feed to cylinder is shut down that the water stops via expansion.

.....Faulty shower mixer valve.

Daniel.

 

[alpina1970]

James ive been time served since 1984 appreciate your thoughts but ive never fitted a gatevalve or isolation to anywhere on the dhw draw off of my poss 1000 hot water cylinders...just not the done thing mate but unless your only suggesting for investigation purposes.

 

[alpina1970]

Thanks Daniel