heating time for immersion shower

jillyb

hey

We have an immersion to heat water for our shower and hot water for the taps. There's a timer in the hot press and outside we have on/off and sink/bank. we were told when we moved in that heating it on sink for half an hour should do for a 20 min shower.

That has worked so far in the ensuite which is a power shower. We had low pressure in the main bathroom as it was gravity fed so hadn't been using it until the landlord recently put in a pump.

Since we've started using the pump I know the water probaby wouldn't last as long but when i heated the water for 40mins I barely got 10 mins of hot water in the shower. We usually have the heating on for a least an hour most days aswell but we haven't had it on the last couple of days-that may have made a difference.

anyone know how long is best to heat for?

thanks

kaizer13

A standard sized 450 x 900 cm cylinder in the hot press will have a total capacity of 117 litres. If yours has a sink/bank option, then it may be of the next size, 140 litres. In sink mode, only about the top third of the cylinder will reach showering temperature and when cold water is mixed in during showering, you may have 60 litres of usable shower water available. Pumping the shower water does provide a more forceful shower but then you must expect the water to be used up faster. The typical pump uses water at around 15 litres per minute so with a 60 litre supply of hot water, expect a comfortably warm shower of about 4 minutes duration. With a well lagged, modern cylinder and 3kW immersion heater, and starting from cold, expect your 60 lires of hot water to take an hour to get up to temperature. This is a very simplified explanation and there are very many factors to take into consideration when trying to formulate a sensible answer to your question. Quite simply, science and the laws of physics will always prevail. A better solution than fitting a pump alone, is to raise the height of the header tank wherever possible. If you need longer showers, then expect to pay the price. Use the bank setting for heating the water, expect to heat for at least an hour, and then you may get 100 litres of usable water which under pump pressure may allow you to enjoy a shower of up to seven minutes duration.

lewis

We live in an area where the water has a fair bit of limescale and I was wondering how much of an effect this can have on the immersion tank over time?
When heating our immersion it was quiet but in the last few weeks its gotten fairly noisy, which cant be good.
Is there a way to protect the tank or something?

jillyb

kaizer13 wrote: »

A standard sized 450 x 900 cm cylinder in the hot press will have a total capacity of 117 litres. If yours has a sink/bank option, then it may be of the next size, 140 litres. In sink mode, only about the top third of the cylinder will reach showering temperature and when cold water is mixed in during showering, you may have 60 litres of usable shower water available. Pumping the shower water does provide a more forceful shower but then you must expect the water to be used up faster. The typical pump uses water at around 15 litres per minute so with a 60 litre supply of hot water, expect a comfortably warm shower of about 4 minutes duration. With a well lagged, modern cylinder and 3kW immersion heater, and starting from cold, expect your 60 lires of hot water to take an hour to get up to temperature. This is a very simplified explanation and there are very many factors to take into consideration when trying to formulate a sensible answer to your question. Quite simply, science and the laws of physics will always prevail. A better solution than fitting a pump alone, is to raise the height of the header tank wherever possible. If you need longer showers, then expect to pay the price. Use the bank setting for heating the water, expect to heat for at least an hour, and then you may get 100 litres of usable water which under pump pressure may allow you to enjoy a shower of up to seven minutes duration.

Thanks Kazier 13,

So basically switch on bath mode and heat for an hour is my best option and i'll still only get 7 mins of hot water??
Thats still not a lot for the length of time heated- don't want to run an expensive ESB bill.

I wonder if i leave it on still while i'm showering would i get more out of it? The min amount of time i need in the shower is 15mins!!