Hot Water Cylinder Volume, seems to have haved !

bkearns

Until recently my hot water cylinder provided enough water for 2-3 showers lasting about 10 mins each. However in the last 2 weeks this has reduced to only 1 shower of 3-4 mins duration!! The initial temperature of the water has NOT reduced, but after 3-4 mins the water temperature drops right off and the hot water cylinder is also cold. Heating radiators or other zones in the Oil fired heating system does not seem to be affected. Does anyone know what the problem could be ?

antiskeptic

bkearns wrote: »

Until recently my hot water cylinder provided enough water for 2-3 showers lasting about 10 mins each. However in the last 2 weeks this has reduced to only 1 shower of 3-4 mins duration!! The initial temperature of the water has NOT reduced, but after 3-4 mins the water temperature drops right off and the hot water cylinder is also cold. Heating radiators or other zones in the Oil fired heating system does not seem to be affected. Does anyone know what the problem could be ?

I take it that the water in the cyl is being heated by the oil fired system and not an immersion.

Water in the cylinder is heated by the central heating in the following way. Hot central heating water (the same water that goes through your rads) is diverted through a coil of copper tubing located in the hot water cylinder. The copper coil gets heated by the water circulating inside it and in turn, it heats the water in the cylinder which is contacting the coils outer surface. There is no mixing of central heating water and water in the cylinder thus.

There'll be a number of electrically operated valves in the system which allows for various configurations (rads on but no hot water heating / heating off in summer but hot water being heated). If the valve which diverts central heating water through the coil is not operating properly (not opening fully) then that would cause you to loose heating capacity. Or if any of the manual valves in the system which are involved in water being diverted through the coil were inadvertently part-shut then that would cause a problem

The electric valve would look something like this with a cable leading out of ithttps://www.google.ie/search?q=myson+diverter+valve&source=lnms&tbm=isch&sa=X&ei=-SWlVPHyHeSv7AbI84DgDg&ved=0CAgQ_AUoAQ&biw=1002&bih=432


An electric valve usually has some kind of indicator to show whether closed or open. Closed should be 90 degrees away from fully open. It also usually has a manual override which allows you open the valve manually so you could try that to see of you can track the problem down - the manual overides can be a bit fiddly so if finding it perhaps go on line to get operating instructions

Dtp1979

bkearns wrote: »

Until recently my hot water cylinder provided enough water for 2-3 showers lasting about 10 mins each. However in the last 2 weeks this has reduced to only 1 shower of 3-4 mins duration!! The initial temperature of the water has NOT reduced, but after 3-4 mins the water temperature drops right off and the hot water cylinder is also cold. Heating radiators or other zones in the Oil fired heating system does not seem to be affected. Does anyone know what the problem could be ?

I'd say you have a leak on the hot water. Don't use any taps or toilets for at least an hour. Then go up to the attic and see if the ballcock in your big tank is refilling. If it is then you've a leak

bkearns

turns out the problem seems to be with the mira mixer on the shower. It would be about 13 years old. Do they fail?

Dtp1979

bkearns wrote: »

turns out the problem seems to be with the mira mixer on the shower. It would be about 13 years old. Do they fail?

How is it the showers fault

whizbang

If the shower was cold, but the hot water cylinder was still hot, then you could blame the mixer.

Check the cylinder before showering, and tell us how far down the hot water extends.