Shower - immersion vs central heating

groengoen

Hi, I have a shower which uses mains cold water for power and hot water from the immersion. In summer I have it timed to come on for a half-hour in the morning and the water is lovely and hot. In winter the central heating kicks in about the same time as the immersion and the pump seems to blow all the hot water away and replace it with lukewarm water. I have the central heating set to 65C and the immersion set to about the same.

Is there some adjustment I can do to the stopcocks to get this balanced?

LIFFY FISHING

groengoen wrote: »

Hi, I have a shower which uses mains cold water for power and hot water from the immersion. In summer I have it timed to come on for a half-hour in the morning and the water is lovely and hot. In winter the central heating kicks in about the same time as the immersion and the pump seems to blow all the hot water away and replace it with lukewarm water. I have the central heating set to 65C and the immersion set to about the same.

Is there some adjustment I can do to the stopcocks to get this balanced?

Your shower should not b connected to the cold mains, it should be connected to your cold water services from your tank, you are suffering from unequal pressure water services, small bit of repiping needed.

groengoen

No, it is a special type of shower which is made with a venturi valve system which equalises the pressure and calculates the temperature.

corkgsxr

There's a valve you can get that balances the pressures. But can ya get at the supply pipes

GreeBo

Is there any chance the stat for the immersion (assuming you have one) has fallen off the tank onto the central pipes?
It might be turning off your immersion before the tank is actually hot?

(random I know)

LIFFY FISHING

groengoen wrote: »

No, it is a special type of shower which is made with a venturi valve system which equalises the pressure and calculates the temperature.

Is your shower a Mira 415 which operates off a combi boiler ?

groengoen

corkgsxr wrote: »

There's a valve you can get that balances the pressures. But can ya get at the supply pipes

I can get at the pipes, but I think that the shower is supposed to be handling this already.

groengoen

LIFFY FISHING wrote: »

Is your shower a Mira 415 which operates off a combi boiler ?

No. It is called a Trevi Boost. The literature says "it is designed to be installed on normal UK tank fed hot supply and mains fed cold supply. The pressure of the cold water is used to boost the pressure of the blended water above that of the hot supply. This is done using the Venturi principle". There are requirements of presssure for both the hot and cold water. Cold between 1.5-3.0 bar. Hot 1 - 3 metres head. It seems that the problem could be too little head on the hot water supply. It is supposed to be at least 1meter above the shower unit and I am not sure if it is.

groengoen

corkgsxr wrote: »

There's a valve you can get that balances the pressures. But can ya get at the supply pipes

I was thinking about this again and maybe this valve is the answer, as the manual says "if direct mains cold water is greater than 3.0 bar, a pressure reducing valve must be fitted. If input conditions are minimal then mixed shower temp may only read 40C".

It seems that the hotter the water is going in, the hotter it comes out so maybe my pressures are minimal.

JohnnieK

Am I right in saying it's ok in the summer than in the winter when the heating is on?

Your immersion stat inside the immersion group is probably set higher than your central heating is.

groengoen

Yes, you are right there, as immersion heater is fine in summer. When I use the central heating the water is hot enough in the hot water tap, but not in the shower.