Hot water temperature setting when using a Combi Boiler

[Juliesm]

I have a Combi boiler. I'm wondering: what's the lowest temperature that I can set the supply to taps at please?

I don't have mixer taps in the house and really don't want 60C hot water coming out of the taps.

 

[ianmcd]

you wont get 60 C with a combi, the way a combi works is that faster the water flows through the boiler the colder the tap temp will be, the faster you run the tap the colder the water will be , the slower you run the tap the hotter it will be , but the boiler wont let you have 60C water temperature , you are mistaking system boilers where the water has to be stored at that temp to prevent legionella

 

[Juliesm]

Hmm. Thank you for your answer. Now then, if I understand you correctly, the temperature I set at the boiler, will not have a positive or negative effect on the growth of legionella in my pipes.

 

[Madrab]

Ideal temp at the outlet is 50 - 55deg.

The water in a cylinder is held @ >60deg, to minimise legionnaire bacteria as it's stored water, that temeratur usually drops to 55deg or lower by the time it gets to the outlet.

Yours, as it's a combi, isn't really affected by the legionnella issue as it's mains, instantaneous, hot water and isn't stored long enough for the bacteria to multiply enough to become a problem. The worst case and as I always recommend to clients, if you are away for 2+ weeks then always run your hot and cold water until it's fully hot/cold to evacuate any water that has sat in the pipes for any length of time. Only issue you may have is if you have any long unused sections of pipework (dead legs).

Same goes for anyone that has lead pipes, always run it every day for a min to clear out any water that was standing in the pipes overnight.

 

[ianmcd]

Hmm. Thank you for your answer. Now then, if I understand you correctly, the temperature I set at the boiler, will not have a positive or negative effect on the growth of legionella in my pipes.

no you are not storing HW with a combi, you heat it as you need it and you wont get 60C out of your tap

 

[Juliesm]

Thanks Madrab Your answer is exactly what I thought. My landlord, housing association, stipulates that the tap water temperature at the boiler should be set at 60C. I usually have it at 42C so that I don't burn my hands. I can't figure out why they say to keep it at 60C, since as you so rightly pointed out "it's mains water".

 

[Madrab]

They'll be using it as a coverall to cover their ass if there were any subsequent problems. As suggested, that approach is for stored hot water.

 

[Juliesm]

Thank you Madrab