Hot water from cold tap in bathroom

emer_D7

First time poster, long time reader.

There is a large water tank in my apartment (approx 10 years old) that holds both cold and hot water. The hot water is heated every morning in the tank. Currently when someone has a shower in the bathroom first thing in the morning the water in cold tap at both the bath and the sink is warm.

The water in the ensuite is fine in both the tap and the shower.
The water in the kitchen is fine also.

There is no way of adjusting the time the water is heated in the morning that I can see from looking at the dial, its fixed. I have turned off the water heater for a night but this does not make any difference. The shower is required everyday in the bathroom for my flatmate.
It seems as though either the water is being heated for too long, or the water is being heated to too high a tempreture.

Any suggestions would be welcome.

Thanks

bbam

Hi..
Could this be hot water feeding back from the mixing point at the shower... I'm presuming the shower is a mixer setup from the hot & cold water supplies.

Has it always been this way ?
Could also be the proximity of the pipes to each ither where they are ran...

Cheers

emer_D7

BBam, thanks for the reply.
As far as I can remember the problem has not always existed, however I used to shower first in the morning in the ensuite and there was never a problem then. I got a new flat mate during august. She showers first in the morning in the bathroom, and this was when the problem arose.

I do remember the cold water being quite tepid or warm in the bath cold tap when there was lots of hot water in the tank. It is as you say a mixer tap, and the water pressure is very strong (pump at the tank).

Not sure about the pipes proximity to be honest,
Emer

ircoha

When u say there is a pump at the tank, is it a single impeller pump or a twin
see
http://www.stuart-turner.co.uk/ for the difference.

If it is a twin, ie both impellers are on when ever the pump is working, then here is my theory:

there is an internal 'leak' in the mixer unit which allows the hot water pass through the mixer unit to the cold side which will occur say when u flush the ceann or run the cold to wash the fiachla before you retire and the pressure in the cold circuit is less than in the hot.
Just a theory.

ps having ruminated on this during dinner, it is possible that the shower mixer unit was not designed for a pressurized system.

emer_D7

Its a single.
It may be possible that its not able to cope with the pressure of the water.
When both hot and cold tap are on, always would need to have cold on much more than hot for a balance of water.

But even when only the cold tap is on the water from that is warm in both the bath and sink in bathroom.


Thanks Irocha

ircoha

emer_D7 wrote: »

Its a single.
It may be possible that its not able to cope with the pressure of the water.
When both hot and cold tap are on, always would need to have cold on much more than hot for a balance of water.

But even when only the cold tap is on the water from that is warm in both the bath and sink in bathroom.


Thanks Irocha

As I said somewhere else: I know what I dont know:) so as I am not familiar with the set up in apartments for a single pump, let me explain what I have here. [The bit I don't know is how the cold water is fed to your cold tank and if the cold in the kitchen sink is directly from the rising main.]

Before describing waht I have in my house, a few comments on your observations.
You may need to reduce the temp on the thermosat on the immersion heater so as to get a more 'equal' mix of hot and cold water.

Is the ensuite shower an electric shower or fed from the hot tank via the pump?

If the 'cold' is always tepid but not in the kitchen it could indicate that the cold in the kitchen is from the 'rising main' and not from the cold water tank.

Is the cold water in the toilet cisterns 'tepid also?.

Following on from my question re the electric shower in the ensuite, it is possible that the ensuite is fed from the rising main and not the tank.

One way of testing what is what is to turn off the pump and see what flows?

The tepid water may be a function of there being no isulation between the hot and cold tanks.

In a normal house set up, the rising main from the road comes in to fill the cold water tank in the attic, with a spur off to the cold tap in kitchen so as this water is always' fresh'.

In a single pump system the cold water feed from the attic tank is pressurized and this then creates the pressure in the hot water tank as well as supplying pressurized cold water. The hot water is always pressurized in the hot water tank , but not the cold as there is no pressurised cold tank and sometimes what happens is when the hot tap is opened, there is a lag before the pump comes on to deliver pressurized cold water so there is lots of hot water before the pump clicks in.

However I dont know about apts so maybe someone else can provide the detail.


over and out

emer_D7

The cold water in the sink in the kitchen is from a mains source (that services the whole apt block).

The Ensuite shower runs off the same system as the bathroom fed from the tank via pump, but perhaps is more equipped to deal with the water pressure.
I'm almost certain that the cold water in the ensuite is run from the tank. (apt used to run out of cold water due to blockage in pipe resulting in slowness of tank to refill, ensuite showers contributed to this).

Didn't think of checking the toliets, but will do.

Will look for a thermostat on tank, that would be the most obvious.
May have to get someone in otherwise.
Thanks for all your thoughts, really appreciate it.

ircoha

Thanks for reply:

Flush the loo in the bathroom a few times in succession and see if the water becomes tepid, this might confirm that the shower mixer unit in bathroom can not take the pressure.
Have u a mixer tap on bath or wash-hand basin? you see why I ask....

jcro

I have a combination hot water and storage tank in my apartment and the cold water gets hot if the imersion heater is on for a few hours. Its a design flaw essentially. Reduce the thermostat setting on the heating elements and if you can start heating the tank closer to getting up time in the morning.