Ideal logic combi2 c30 help please

Little_miss_dfw

Hi, for years I had a very old boiler with a hot water tank so I just left it alone at the temperature it was set at. 

The gas prices were eye watering and after being told I was basically losing 30% of the energy generated out the flue I got the above boiler fitted. 

I’ve noticed that my gas bills have really reduced but I have a quick question about the hot water. 

At the min my hot water is set to 60 on the boiler. I’ve noticed that the hot water from my taps are so hot they produce steam. 

What is the lowest/ safest temp I can lower this too? And what temp do you recommend so I can have hot water without it scalding me?
any advice will be greatly received 

Alnat1

A combi boiler heats cold water as you need it so there is no unsafe lower temperature. Try 50C and see how you get on, adjust it higher or lower until you get it how you want it.

Little_miss_dfw

Thank you. 

As I have only ever had the boiler with the water tank, and know it cannot be below a certain temp, I wasn’t sure if it was the same for condenser boilers

FreeBear

Alnat1 said:

A combi boiler heats cold water as you need it so there is no unsafe lower temperature. Try 50C and see how you get on, adjust it higher or lower until you get it how you want it.

Go lower and try 45°C

With a combi, there is almost zero risk of legionella (the usual excuse for heating water to 60°C or more). As a bonus, you should save on gas as you don't need to heat the water to such extreme.

Coffeekup

During the summer I have my combi boiler water set to 40° and in the colder months 43°.
This saves me having to mix in the cold water tap when in the shower and it also is perfect temperature to wash the dishes with.
I guess it saves gas usage as it doesn't need to burn as much gas to reach a higher temperature, but I haven't tested it to find out actual numbers.

That being said you have a water tank so I'm unsure how your boiler heats the water. I hear water tanks need a 60° legionella burn once a week.
My boiler being a combi the hot water comes straight from that.

BTW Scalding temperature is 44° 

Little_miss_dfw

I’ve just had a combo boiler installed. The plumber set it to 60 so I have just left it at that but the hot water is so hot there is steam. I’ll give 50 a go and go from there. Thank you. 

daveyjp

Summer low 40s, winter high 40s.

FreeBear

Coffeekup said: That being said you have a water tank so I'm unsure how your boiler heats the water. I hear water tanks need a 60° legionella burn once a week.

Whilst it is true that the Legionella bacteria dies within minutes at 60°C, it is not necessary. Heat the tank (if you have one) to 50-55°C and keep it at that temperature for a few hours will have the same effect. That said, Legionella is very rare in the UK, with just some 250 cases reported each year. Of those, half are often contracted overseas.

Have (had) an open vented HW cylinder here, and only heated the water to 52°C once a week - A major contribution to cutting gas consumption.

All of the above is a moot point for the OP as they have a combi, so no stored hot water.

markin

Use Eco, or turn off pre heat, no need to heat a tiny tank in the boiler, if it has one.

jefaz07

markin said:

Use Eco, or turn off pre heat, no need to heat a tiny tank in the boiler, if it has one.

The logic will have a pre heat. I always turn them off. Pointless. 

Little_miss_dfw

I’ve already turned off the preheat. The plumber advised me to do this.