Torrent hot water cylinder problems

[sasik]

Hi
My costumer have a Torrent direct hot water cylinder with a mixing valve on the hot outlet from the cylinder. The problem is, when he tray to draw hot water at the taps he get good flow of hot water for about 10 second and then it turn cold. I replaced the mixing valve assuming it was faulty but I still can't get hot water at the taps. I tested both of the water heating elements and they both work fine (plenty of hot water in cylinder). There is a pressure reducing valve on the cold incoming supply (set at 3bar) that might by faulty but I am not sure.
I don't know where is the problem and why he can't get hot water like he use to.
If any of you can help, please send your coments.
Thanks sasi

[plumbnuts]

Hi sasi
This is a thermal store direct cylinder. The water in the cylinder is static and topped up from a F&E tank which is heated from the immersion heaters and the cold water main passes through a coil and is instantly heated. You say that the water in the cylinder is hot - What teperature is it?
have you checked the correct operation of the thermostats on the immersions.
Steve

[sasik]

Both element set between 65c and 70c. when I draw water very hot but not for long(about 10sec). When you run hot water in the tap you can fill how the flow increase as the hot water mixing with the cold water.

I am not quite sure how this cylinder work. It's vented cylinder but it supply hot water in main pressure. Directly on top of the main body of the cylinder you have a small f&e tank (the manufacture recommend only couple of inches of water)

Do you think if the pressure reducing valve don't work right the cold water flow over power the flow of hot water when they both come in to the mixing valve?

[Mike Jackson]

The coil could be scaled up. This would lead to extended heat up times for the hot water so that the initial draw would be hot but very soon run cold.

Mike

[sasik]

I don't think this cylinder have a coil, it's a direct cylinder with two heating elements. The main one at the bottom and the immersion heater half way the cylinder.