Hot Water Temperature
Discussion
55 to 65'C is standard. Any higher increases the risk of burns.
I believe that bacterial growth is prevented at those sorts of temperatures but to actually kill the bacteria much higher temps are needed. Some commercial systems perform a pasteurisation out of occupancy to kill bacteria.
Catherine - if your bath was actually 60'C and you got in it then you must be made of asbestos! I would suggest that while your thermostat might be set at 60 there could be something wrong with it.
I believe that bacterial growth is prevented at those sorts of temperatures but to actually kill the bacteria much higher temps are needed. Some commercial systems perform a pasteurisation out of occupancy to kill bacteria.
Catherine - if your bath was actually 60'C and you got in it then you must be made of asbestos! I would suggest that while your thermostat might be set at 60 there could be something wrong with it.
stefd said:
55 to 65'C is standard. Any higher increases the risk of burns.
I believe that bacterial growth is prevented at those sorts of temperatures but to actually kill the bacteria much higher temps are needed. Some commercial systems perform a pasteurisation out of occupancy to kill bacteria.
Catherine - if your bath was actually 60'C and you got in it then you must be made of asbestos! I would suggest that while your thermostat might be set at 60 there could be something wrong with it.
I guess I need to stick a thermometer under the flow to get a reading and see what it's coming out at. From memory it has been like this for quite some time, certainly since we had a new heat exchanger in it in November 2008.I believe that bacterial growth is prevented at those sorts of temperatures but to actually kill the bacteria much higher temps are needed. Some commercial systems perform a pasteurisation out of occupancy to kill bacteria.
Catherine - if your bath was actually 60'C and you got in it then you must be made of asbestos! I would suggest that while your thermostat might be set at 60 there could be something wrong with it.
Edited to add: The only thermometer I have is a medical one. It recorded 43.5 but then displayed a H, so I need to get a more appropriate model.
Edited by CatherineJ on Monday 11th January 15:23
I was chatting to a work colleague earlier who was telling me about his central heating / boiler related woes over Xmas.
Apparently his combi boiler will only heat to something like 40 degrees C above ambient cold water temperature hence the reason he was getting only hot water out of his boiler rather than scalding hot. He had BG round to check it out and they checked ambient cold water mains temp (3 degrees) versus what was coming out of the taps (40 something degrees).
Their advice, particularly for baths etc was to run the tap slower.
Don't know if this applies to you, Catherine?
Apparently his combi boiler will only heat to something like 40 degrees C above ambient cold water temperature hence the reason he was getting only hot water out of his boiler rather than scalding hot. He had BG round to check it out and they checked ambient cold water mains temp (3 degrees) versus what was coming out of the taps (40 something degrees).
Their advice, particularly for baths etc was to run the tap slower.
Don't know if this applies to you, Catherine?
Ah now if the kitchen tap is run slowly, it will get so hot it will burn your hand off.
I suppose the other issue is that the Bath hot tap doesn't run that quickly in the first place, so if I run it any slower it will taken 30 mins to fill the bath.
I suppose the other issue is that the Bath hot tap doesn't run that quickly in the first place, so if I run it any slower it will taken 30 mins to fill the bath.
Edited by CatherineJ on Monday 11th January 15:55
Simpo Two said:
GregE240 said:
Their advice, particularly for baths etc was to run the tap slower.
Ha, so much for progress!Your combination boiler should have been set up by the installer to give a designed flow rate. This will give the designed temperature rise. The problem is that morons who don't read instructions don't throttle the boiler and therefore the temperature rise is never reached due to too high a flow rate.
The water does not need to be above 65 degrees, since it isn't stored. In reality 35 degrees temperature rise is about right for a cheap combination boiler. You probably couldn't keep your hand under much over 40.
The water does not need to be above 65 degrees, since it isn't stored. In reality 35 degrees temperature rise is about right for a cheap combination boiler. You probably couldn't keep your hand under much over 40.
Stored hot water is supposed to be 55 degrees or above to kill legionnaires disease, in reality 50 degrees is fine - also copper cylinders kill it and in reality it is impossible to catch from a domestic installation.
Pass through water heating systems (such as a combi) will struggle when the inlet water temperature is low (well, the small ones will). Typical shower/bath temperature is 40, - with a prolonged cold spell the ground temp will fall and it will take a lot more energy to heat it.
There is no point in storing hot water at high temperatures - it just wastes energy. It doesn't matter too much instantly heating water to high temperatures and mixing with cold as the wastage is small.
Pass through water heating systems (such as a combi) will struggle when the inlet water temperature is low (well, the small ones will). Typical shower/bath temperature is 40, - with a prolonged cold spell the ground temp will fall and it will take a lot more energy to heat it.
There is no point in storing hot water at high temperatures - it just wastes energy. It doesn't matter too much instantly heating water to high temperatures and mixing with cold as the wastage is small.
CatherineJ said:
Ah now if the kitchen tap is run slowly, it will get so hot it will burn your hand off.
I suppose the other issue is that the Bath hot tap doesn't run that quickly in the first place, so if I run it any slower it will taken 30 mins to fill the bath.
We had a safety mixer valve fitted to our bath (I'm not sure of the proper name- I'm sure Ferg will know). You can't see it as it sits underneath the bath. It has been set so that the hot water exiting the bath tap is significantly below 60degC. We had the bathroom installed when we had very young kids. The safety mixer valve was fitted so that we couldn't scald the kids. You may have one of these fitted. The hot water from all other taps is unaffected is extremely hot.I suppose the other issue is that the Bath hot tap doesn't run that quickly in the first place, so if I run it any slower it will taken 30 mins to fill the bath.
Edited by CatherineJ on Monday 11th January 15:55
pp
Ferg said:
You probably couldn't keep your hand under much over 40.
Interesting, I've been in Dubai when it's been hotter than 40 degC, indeed I once saw 50 degC on the temp gauge in the hired BMW. So why would water in a container at ambient outside temperature there not be scalding? 
GregE240 said:
I was chatting to a work colleague earlier who was telling me about his central heating / boiler related woes over Xmas.
Apparently his combi boiler will only heat to something like 40 degrees C above ambient cold water temperature hence the reason he was getting only hot water out of his boiler rather than scalding hot. He had BG round to check it out and they checked ambient cold water mains temp (3 degrees) versus what was coming out of the taps (40 something degrees).
Their advice, particularly for baths etc was to run the tap slower.
Don't know if this applies to you, Catherine?
QED & why I'd avoid a combi boiler like the plague.Apparently his combi boiler will only heat to something like 40 degrees C above ambient cold water temperature hence the reason he was getting only hot water out of his boiler rather than scalding hot. He had BG round to check it out and they checked ambient cold water mains temp (3 degrees) versus what was coming out of the taps (40 something degrees).
Their advice, particularly for baths etc was to run the tap slower.
Don't know if this applies to you, Catherine?
Iain328 said:
GregE240 said:
I was chatting to a work colleague earlier who was telling me about his central heating / boiler related woes over Xmas.
Apparently his combi boiler will only heat to something like 40 degrees C above ambient cold water temperature hence the reason he was getting only hot water out of his boiler rather than scalding hot. He had BG round to check it out and they checked ambient cold water mains temp (3 degrees) versus what was coming out of the taps (40 something degrees).
Their advice, particularly for baths etc was to run the tap slower.
Don't know if this applies to you, Catherine?
QED & why I'd avoid a combi boiler like the plague.Apparently his combi boiler will only heat to something like 40 degrees C above ambient cold water temperature hence the reason he was getting only hot water out of his boiler rather than scalding hot. He had BG round to check it out and they checked ambient cold water mains temp (3 degrees) versus what was coming out of the taps (40 something degrees).
Their advice, particularly for baths etc was to run the tap slower.
Don't know if this applies to you, Catherine?
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