Cold weather-Immersion needs longer to heat water?

girlnamedgrace

Hello!

Ok, so bear with me as I have a very rudimentary understanding of immersions etc. In October we moved into a place that has a immersion shower, previous to this I always lived with electric showers.
Our heating is gas, and we use the 'boost' button to heat the house for an hour, which provides some hot water in the taps.(Enough for washing up etc.) When we need a shower, we flip the 'fast immersion' switch, and after maybe 20-30 minutes there's hot water for a shower.
October was fairly mild weather wise, the heating wasn't on much, and after 20-30 minutes the water for the shower was good and hot and lasted for the length of a nice long shower.

However.....

Its now after getting quite cold, and yesterday and today I had fairly cold showers! There was no one in the house all day Monday so there was no heating on. I had the immersion on for 40 minutes Tuesday morn and the water never got hot enough for my shower. We were out all day yesterday, so no heating on again. This morning I had the immersion on for an hour and had a cold shower again. Not freezing cold mind, but definitely uncomfortable!

My theory is that this has something to do with the weather? The house is cold as the heating hasn't been on, meaning the water tank is at its coldest, and therefore will take longer to heat than usual? Though after an hour I expected it to be quite warm!

Any ideas?

b318isp

Can you explain what you mean by an "immersion shower". From reading your post, I assume it is a hot water tank heated both by a boiler and an electric immersion?

If so, the immersion should give you enough hot water for a shower within 30-40 minutes if the water in the tank is cold to begin with.

If you are not getting enough hot water then I would check for:

- Loose wiring connections on immersion system (switch and immersion element)
- Thermostat on the immersion faulty or set too low
- Failing immersion element

Do you have a dual immersion (hi/lo or sink/bath) switch - if so, try the switch in the setting that you don't nnormally use.

girlnamedgrace

Its one of those ones with the hi/lo bath/sink switches, but there's another switch with a redlight on it that we use instead.

Would the thermostat be up beside the hot water tank?

b318isp

Err, do you switch the sink/bath switch at all - and in what position is it when you want to heat the water?]

Where is this switch located relative to the "other" switch with the red light?

[It is possible that the "other" switch is a feed switch for isolating the supply.]

The thermostat is in the head of the immersion element in the hot tank. As there are open electrical terminals in there, it should only be opened up by someone competent with electricity.

girlnamedgrace

We never use the bath/sink switch, we always use the one with the red light. Its on the wall, about shoulder height, to the right of a doorway. Then up over the doorway, in a cupboard, sits the water tank. (bad description, but trust me, that's where it is!)

I'll tell the landlord we need an electrician out so. I just wasn't sure if it was the weather causing the problem.

Thanbks for the advice!

b318isp

What position are the switches left in on the sink/bath switch - and is there a red light on it?

Bruthal

In colder weather, the immersion will take longer to heat the water to the same temperature.

Also, the cold water you mix in with it at the shower will also be colder, meaning you will have the hot tap/dial on a higher flow rate to get the same flow rate and/or temperature output.

So colder weather can influence the mixer shower performance and heat input required to the water.

This will be the case, and is the probable cause here, assuming the immersion is working properly as it was before.

b318isp

robbie7730 wrote: »

This will be the case, and is the probable cause here, assuming the immersion is working properly as it was before.

But an hour is plenty long enough for the water to get to shower temperature, even given the colder incoming water.

Bruthal

b318isp wrote: »

But an hour is plenty long enough for the water to get to shower temperature, even given the colder incoming water.

It should be. It might not be working properly.

But we don`t know what type of shower it is, or what the setup is at all really. Is the mixer shower left at the same settings? The cylinder will heat the water to the same temperature as before, just taking longer, but the cold water being mixed with hot in the shower will be a lot colder than a few weeks ago, so a shower at the same settings will be colder, even with the same temperature/volume of hot water going to it.

Do we know if the water is still fine from the hot taps? Not really.

Like I said already, the colder water could be the problem, if all else is working as it was. I am not suggesting there is nothing wrong with the heating setup. More info needed.

Is the hot water from the taps the same as it was? Did the op try leaving the gas boiler on for a couple of hours to indicate a problem with the immersion?

It is cheaper to heat the cylinder of water with gas than immersion.

johnwest288

I know on myMynute boiler there is a low setting and high setting. I looked up the manual and it said the higher setting was for winter months On normal setting during winter it takes ages and doesnt heat enough water as it does in summerz

2011

+1 to what Robbie has said.
In addition:

girlnamedgrace wrote: »

Our heating is gas, and we use the 'boost' button to heat the house for an hour, which provides some hot water in the taps.

From the description given it is clear that as with many homes the water can be heated by the immersion and/or the gas boiler. Therefore if the OP normally has the boiler on the water is partially heated by it in which case the immersion is required to change the temperature of the water by a reduced amount.

Its now after getting quite cold, and yesterday and today I had fairly cold showers! There was no one in the house all day Monday so there was no heating on.

In this case the water would have to have been heated solely by the immersion from a far lower temperature without the assistance of the boiler.

I had the immersion on for 40 minutes Tuesday morn and the water never got hot enough for my shower. We were out all day yesterday, so no heating on again.

As above.

johnwest288

Sounds Silly but...Would strapping another 2 lagging jackets onto the tank make much of a difference or more hassle than worth? So in Effect 3 layers of lagging jackets

b318isp

2011 wrote: »

In this case the water would have to have been heated solely by the immersion from a far lower temperature without the assistance of the boiler.

The degree of this will depend on the amount of HW used. If there is a lot, then the extent will be greater = more water from CW tank. If HW consumption is low then the water sitting in the HW tank will be warmer than that in the CW tank in the attic, so less of an effect.

Even so, I still maintain that 2-3kW is sufficient to get around 10 litres of water from even 7 deg C to 40 deg C in 40 minutes.

I can only assume that the OP has tried turning up the mixer valve, but could be wrong. I agree that checking the HW taps could rule this out.

2011

b318isp wrote: »

If HW consumption is low then the water sitting in the HW tank will be warmer than that in the CW tank in the attic, so less of an effect.

Clearly, but it will still have an effect.

Even so, I still maintain that 2-3kW is sufficient to get around 10 litres of water from even 7 deg C to 40 deg C in 40 minutes.

If the OP had a 10 litre tanks I would agree.

However it is far more likley that the tank is much larger (I would expect the volume to be in excess of 100 litres).

But I agree that it would appear that the immersion may not be performing well. At this pint we simply do not have enough information to say so conclusively. For all we know it is a 1kW element on a larger unlagged tank in a very cold house.

b318isp

2011 wrote: »

b318isp wrote: »

If HW consumption is low then the water sitting in the HW tank will be warmer than that in the CW tank in the attic, so less of an effect.

Clearly, but it will still have an effect.


If the OP had a 10 litre tanks I would agree.

However it is far more likley that the tank is much larger (I would expect the volume to be in excess of 100 litres).

Of course, but no more than 10 litres would be needed for a shower, and the water at the top of the tank would be hottest.

2011

b318isp wrote: »

Of course, but no more than 10 litres would be needed for a shower, and the water at the top of the tank would be hottest.

But the immersion may be installed low in the tank. Even if it is at the top of the tank it will extend to a depth below the 10 litre level of the tank.

Besides 10 liters is not much for a shower.

b318isp

2011 wrote: »

But the immersion may be installed low in the tank. Even if it is at the top of the tank it will extend to a depth below the 10 litre level of the tank.

Besides 10 liters is not much for a shower.

The warmed water rises.

2011

Warmer water rises, but it is not possible to heat only 10 liters in a standard hot water tank with a standard element. This is the case in a typical arrangement due to the length & position of the element and the size and shape of the tank.

It is all academic anyway as 10 liters is not enough, nor is 40 DegC.

b318isp

2011 wrote: »

It is all academic anyway as 10 liters is not enough, nor is 40 DegC.

Figures are only representative of those for a minimal shower. For the OP, if you can't get this with an immersion on for 40+ minutes, then my point is that is problem is likely to be the immersion, not the cold water.

Bruthal

b318isp wrote: »

Figures are only representative of those for a minimal shower. For the OP, if you can't get this with an immersion on for 40+ minutes, then my point is that is problem is likely to be the immersion, not the cold water.

It could be an immersion problem, but if the OP is not going to do very simple common sense checks and report back, then all we can do is suggest possible causes.

2011

robbie7730 wrote: »

It could be an immersion problem, but if the OP is not going to do very simple common sense checks and report back, then all we can do is suggest possible causes.

Exactly.

Nobody can state anything conclusive as we simply do not have enough information.