Immersion timer & shower query

We have just put a new shower (and attached pump to improve pressure) and new hot water tank into the house. The tank is much bigger than before and obviously with the extra pressure due to the pump its uses much more hot water per shower.

We are still trying to see amount of time immersion needs to be on to heat the tank for two showers in the morning.

Q -- Is there any way of working out the most economical amount of time to have the immersion on to heat the tank as obviously we don’t want it on for ages using up electricity.

Currently we have it for 2 hours and it is only giving us about 5 mins of hot water in shower. We don’t have central heating on at present hence just using the electric immersion

have raised this query with a builder who put the new tank / immersion in.

He has said the most economical thing is to leave the immersion on over night as the thermostat will control the temp. in the hot water tank and this would be better than just turning it on for a few hours before we get up to ensure hot water for showers in the morning.

i am pretty sceptical about this -- has anyone got an experience of it as dont want to run up massive elec bills for hot water when heating is not on.

I'd be sceptical about the builder's advice myself. The thermostat will contol it so that the heating element won't burn out but aside from that it will still heat a full tank of water and then keep that heated throughout the night. If you're in a appartment and have cheap nighttime electricty then it mightn't be a problem.

We have a pump on our shower and it's pretty powerful (I hate showers where you have to run around to get wet). I only have to leave it on for 30 minutes to get enough for a 10 minute shower and there's still plenty hot water left.

Jo, I would think there is something wrong somewhere if you are only getting 5 mins hot water from your tank. A pumped shower might use depending ont he pump up to 30% more water than a normal shower but I would say that a tank full of hot water would give around 15 min shower time. When you think about it you would definately fill a bath with a tank heated for 2 hours. A simple solution might be that the thermostat in your immersion is turned down very low therfore not actually heating the water very much, it might be work a look.

Another thing Jo, do not leave your immersion on overnight unless you have night rate electricity as it will be very expensive. This will not solve the underlying problem. Another problem might be that the bath element in your immersion might not be working.

Jo90 said:

Currently we have it for 2 hours and it is only giving us about 5 mins of hot water in shower.

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IMHO that's a tank problem. We went though something similar with the tank that was in the house when we moved in. We eventually got it replaced and the difference is significant.

thanks for the replies.

actually timed amount of hot water coming through and set it for the sink immersion switch and it gave 5mins of hot water when on for same amount of time. the actul time for the bath switch is only 3 minutes in total (less than my 5 min estimate before)

am going to talk to the electrician as it does seem very strange and could be the bath element is not operating as efficiently as it should.

Bue5Off -- this may be a silly question if the tank is heated using the gas boiler same as heating through the bath immersion or will this be totally different as may try that to see how much shower time should be in a full hot tank.

thanks for the help.