Hot Water Cylinder Problem?

[Chet67]

We have recently had a Greenstar 30CDi system boiler installed with an Integral Diverer Valve together with a Telford 170 litre horizontal hot water cylinder, the system was installed by a Corgi registered plumber.
Unfortunately we a have a problem that the plumber cannot solve namely if we run two showers the water goes cold after about three minutes and doing a check by measuring a full tank of hot water into a bath the water becomes luke warm after approximately 65 litres of hot water has been draw .
I do not know if it’s relevant but when drawing a glass of hot water it’s cloudy/ milky colour but readily clears I can only assume it’s slightly aerated.
Has anyone got any idea what the problem might be?

 

[mrgas]

A big shower head can use 40lts/min
two shower therefore can use 80lts/min
Hot water runs out after 65LTS of hot water on a 170lt cylinder?
Is the cylinder stat located correctly?

I take it it is an unvented cylinder,in which case the cloudy water is just normal entrained air bubbles as you say clear quickly from the bottom of glass up, and nothing to do with your lack of hot water problem.

Are you sure that its horizontal? Can you post a picture?

 

[Chet67]

The two showers are average size heads, but the pressure is quite high which could result in 60 to 80 litres being used but it would be a mixture of hot and cold water.
It’s definitely a horizontal tank, the thermostat is at the bottom, only thing is there appears to be two, one from the boiler and the other part of the tank but they both are attached at the at point, why two stats?

Hope you can see the photo.

 

[mrgas]

I hope i'm wrong, but ive got alarm bells ringing!
Is your installer qualified for unvented hot water storage?
Looks to me like a normal pressure relief valve on top of cylinder instead of temp/pressure relief and I cant see any moterised valve to provide thermal cutoff........
I hope im wrong I'm not familular with Telford..anyone else..

 

[Agile]

Untitled

• Chet67
• 25 Mar 2009
• 1

That cylinder does not look very large compared with the expansion vessel ! Are you totally sure its a nominal 170 litres?

Be aware that horizontal cylinders heat a much smaller proportion of their volume than a vertical one.

Also as stated it seems to be just a pressure relief valve and NOT a T&P valve as required by the regulations.

There is no spring return two port valve as required to be connected in series with an over heat stat.

Its seems pretty clear to me that the installer is a DIYer operating illegally or a cowboy operating illegally!

The official advice would be to remove all sources of heat until it has been properly checked by someone who is qualified as it could

EXPLODE !

Cue BigBurner !

Tony

 

[mrgas]

Assuming it hasnt exploded yet and you are still with us could you tell us when it was installed?

 

[mrgas]

Spoke with tech from Worcestrer today, he tells me the internal diverter valve is no longer "legal" fitted to unvented cylinders.