How to reduce water temperature?

jackieblack

Jeepers_Creepers said:

Hi Jackie.

As asked above, won't your boiler heat your hot water tank without also heating your radiators? Heating by gas would usually work out cheaper than using electricity.

What kind of boiler do you have? And what type of controls? (Can you post photos of both?)

Yes, the boiler would heat the water separately, but when my solar panels are at peak generation it’s cheaper to use the immersion - I’ve been doing it this way for over 10 years. 
Also my boiler is over 20 years old so I try to use it only when necessary.

getmore4less

If you just have the immersion on when the electricity is free having the tank hot gives store for times you can't get it heated free.
Just mix with cold.

Jeepers_Creepers

jackieblack said:

Yes, the boiler would heat the water separately, but when my solar panels are at peak generation it’s cheaper to use the immersion - I’ve been doing it this way for over 10 years. 

Also my boiler is over 20 years old so I try to use it only when necessary.

Thanks for the explanation, Jackie - that sounds fair enough!

As GM4L says, if you are getting your power for free, then having the tank 'too hot' shouldn't be an issue - it just means more free hot water.

But, you now know how to control the immersion temp, so it's your call where to set it.

Good advice from others above too - keep it above 60oC to remove the risk of Legionnaire's, and be 100% certain to isolate the power supply before tinkering.

You'll find the 'stat control is very crude to regulate, so might be worth setting the arrow comfortably above the '60oC' (say, 65oC) spot to ensure it actually is at 60oC or more. Could you also note what setting it's currently at before you move it? If it's pointing nicely above 70oC, then that would explain the 'too hot' bit! BUT, if it's already pointing at only, say, 60oC, that would suggest a faulty 'stat.

The 'stat should audibly 'click' as you dial it above and below the actual water temp in the cylinder - can you check that it does?.

jackieblack

The problem with the ‘too hot’ water is that my shower runs either too hot or too cold - I can get the mix right and it’ll be fine for a few seconds then it goes cold and I have to turn it off, start it going again with no cold water coming through (scalding hot) and adjust it gradually until I get the right temperature again, and then repeat the process half a dozen more times - I spend more time faffing about with the temperature of the water than I do standing under it!
 I don’t have this problem if the water has been heated by the boiler as, I assume, the thermostat for that system must be set to a lower temperature 🤷🏻‍♀️

jackieblack

Jeepers_Creepers said:

You'll find the 'stat control is very crude to regulate, so might be worth setting the arrow comfortably above the '60oC' (say, 65oC) spot to ensure it actually is at 60oC or more. Could you also note what setting it's currently at before you move it? If it's pointing nicely above 70oC, then that would explain the 'too hot' bit! BUT, if it's already pointing at only, say, 60oC, that would suggest a faulty 'stat.

The 'stat should audibly 'click' as you dial it above and below the actual water temp in the cylinder - can you check that it does?.

👍🏻 Thanks, I’ll have a look when I get in tonight (I ran out of time last night)

Jeepers_Creepers

jackieblack said:

The problem with the ‘too hot’ water is that my shower runs either too hot or too cold - I can get the mix right and it’ll be fine for a few seconds then it goes cold and I have to turn it off, start it going again with no cold water coming through (scalding hot) and adjust it gradually until I get the right temperature again, and then repeat the process half a dozen more times - I spend more time faffing about with the temperature of the water than I do standing under it!
 I don’t have this problem if the water has been heated by the boiler as, I assume, the thermostat for that system must be set to a lower temperature 🤷🏻‍♀️

It's not a thermostatic shower mixer, then? If it is, then it's faulty!

There's also the possibility that the hot is from your stored water system (tank in the loft?) but the cold to your taps is direct from the mains. That would mean the two supplies are at a completely different pressure, so balancing them manually (even thermostatically) will be very hard.

Yes, it's possible that the gas boiler delivers water to the cylinder at a lower temp, but we can't tell from this side of the screen

Greatgimp

Seems illogical to me to have to cool hot water down to use it. Reduce temp st thermostat (but above 60ºC), means that excess free electric could go into the grid at 5p per kwh or so.

jackieblack

Jeepers_Creepers said:

jackieblack said:

The problem with the ‘too hot’ water is that my shower runs either too hot or too cold - I can get the mix right and it’ll be fine for a few seconds then it goes cold and I have to turn it off, start it going again with no cold water coming through (scalding hot) and adjust it gradually until I get the right temperature again, and then repeat the process half a dozen more times - I spend more time faffing about with the temperature of the water than I do standing under it!
 I don’t have this problem if the water has been heated by the boiler as, I assume, the thermostat for that system must be set to a lower temperature 🤷🏻‍♀️

It's not a thermostatic shower mixer, then? If it is, then it's faulty!

There's also the possibility that the hot is from your stored water system (tank in the loft?) but the cold to your taps is direct from the mains. That would mean the two supplies are at a completely different pressure, so balancing them manually (even thermostatically) will be very hard.

Yes, it's possible that the gas boiler delivers water to the cylinder at a lower temp, but we can't tell from this side of the screen

Hot is from the cylinder (in airing cupboard on the other side of the wall from the shower). I thought the cold water comes from the cold water tank in the loft, but I could be wrong.
I only have the problem in the shower when I’m using water heated using the immersion, so I don’t think it’s a problem with the shower mixer.

jackieblack

Greatgimp said:

Seems illogical to me to have to cool hot water down to use it. Reduce temp st thermostat (but above 60ºC), means that excess free electric could go into the grid at 5p per kwh or so.

Excess electricity does feed back to the grid but I get paid for a deemed export of 50%, irrelevant of how much actually goes back. Export payment is a tiny fraction compared to the generation payment anyway.

Jeepers_Creepers

jackieblack said:

Hot is from the cylinder (in airing cupboard on the other side of the wall from the shower). I thought the cold water comes from the cold water tank in the loft, but I could be wrong.
I only have the problem in the shower when I’m using water heated using the immersion, so I don’t think it’s a problem with the shower mixer.

That is, indeed, the right way. And since the hot from the cylinder is also 'driven' - supplied - by the same cold tank in the loft, then both supplies should arrive at the shower at the same pressure and roughly the same rate. Therefore, 'blending' the two in order to get the right temp should be easy.

When you turn on a cold tap and a hot tap, do they flow at roughly the same rates, or is the cold a LOT faster/more powerful (it'll likely be slightly more) than the hot?

Is your shower 'thermostatic'? Does it have a oC scale on the temp control?