gas combi boiler temp for colder months?

[BobbyJoe]

Morning everyone,

Now that the outside temperature is decreasing the incoming water such as DHW is cooler, is turning the DHW dial to around 55 degrees Celsius on a gas combi boiler reasonable and safe. My boiler goes from a minimum of 37 to max 60 degrees according to the manual.

From summer up until last month I had it turned to around 41/42 degrees. Water is mains fed, I have mixer taps throughout the flat (2nd floor), thermostatic shower, water is 9 litres pm and 35 degrees rising main.

I don't have anything on the gas combi boiler which shows me what the DHW temperature is, so I use a digital thermometer to check.

Any advice would be greatly appreciated thank you.

 

[Ben-gee]

Yes it’s safe.

 

[hometech]

Morning everyone,

Now that the outside temperature is decreasing the incoming water such as DHW is cooler, is turning the DHW dial to around 55 degrees Celsius on a gas combi boiler reasonable and safe. My boiler goes from a minimum of 37 to max 60 degrees according to the manual.

From summer up until last month I had it turned to around 41/42 degrees. Water is mains fed, I have mixer taps throughout the flat (2nd floor), thermostatic shower, water is 9 litres pm and 35 degrees rising main.

I don't have anything on the gas combi boiler which shows me what the DHW temperature is, so I use a digital thermometer to check.

Any advice would be greatly appreciated thank you.

the output of 55 is rated as max but in reality it will never achieve this (water flow rates/gas rates/input temp). High flow rate means less water heated in the time it goes through the exchanger. ps the cooler temp input water does not drop as much as you believe it does. The lowest recorded cold water feed was 5 degrees

 

[Chuck]

Now that the outside temperature is decreasing the incoming water such as DHW is cooler, is turning the DHW dial to around 55 degrees Celsius on a gas combi boiler reasonable and safe.

It's safe, as long as you don't have vulnerable adults or children in the dwelling who might scald themselves. It's also pointless because the dial is not a power control it's the set point on a thermostat; the boiler adjusts the power used to heat water to the set point and in the process compensates for both flow rate and inlet temperature.

 

[hometech]

 

[cjg]

turn it to full and leave it there, if water is still cool turn your hot tap down a little so the boiler can heat it to the right temp. your flow rate will be slower going though the heat exchanger.

 

[BobbyJoe]

Thank you so much for the helpful advice, the DHW water is adequately hot at 50 degrees throughout the flat, if I need to turn it to 60 degrees next month or when necessary then I will.
I will turn the DHW down to 38/40 degrees when elderly family members visit as they in their homes they have blending valves installed to prevent scalding.

Also are the temperature dials on gas combi boilers accurate, and is it better having a LED/digital screen on boiler which shows you what the temperature is?

 

[cjg]

temperature dials on gas combi boilers accurate, no but close.

 

[John.g]

Mains water temp certainly changes a lot around here from 7C in winter to ~ 17C in summer which means that a 30kw combi will give flowrates of 13.0/18.7LPM at 40C winter/summer.