Boiler challenge - cut gas bill by £100/yr

Joe9090

In Martin's latest weekly email https://www.moneysavingexpert.com/latesttip/?utm_source=MSE_Newsletter&utm_medium=email&utm_term=08-Nov-22-01251efa3d448588db9-636aad7bc65b0e4381b90a09098c903e&source=CRM-MSETIP-01251efa3d448588db9&utm_campaign=nt-viewonlineheader&utm_content=1 it appears you cannot turn down the boiler flow temperature if you have a non combi boiler that supplies a hot water tank. We have an Ideal Logic Max 24 with a hot water tank! Why are they saying this saving does not apply to the boiler we have?

Miser1964

You need the HW supply to be above 60C to kill off bugs that can multiply in the tank water, esp. Legionella pneumophila

ariarnia

you don't need the boiler to be constantly above 60 do you? i thought i read on here some people turned it up one day a week to kill anything off. so you could still save vs keeping it at 60 all the time. 

but i think the best way to save energy with a hot water tank is to really go for lagging everything. we have a combi but when the rads are on there are some spots on the floor upstairs where you can feel a little heat and i'm trying to track all of these down so we can lift the floors and look at some insulation around the pipes. to make sure the heat is going where we want it to not leaking from the system. 

Miser1964

ariarnia said:

you don't need the boiler to be constantly above 60 do you? i thought i read on here some people turned it up one day a week to kill anything off. so you could still save vs keeping it at 60 all the time. 

Some system boiler controllers will automatically run a 'hot' cycle once a week to control bacteria. 

That said, new installations should be setup as Priority Domestic Hot Water with different temps for CH and HW. But it'll take years for lazy installers to stop using S-plan or Y-plan. 

Ally_E.

I have a system boiler and turn the flow temperature up when it's heating water and then down for central heating. I have an alarm on my phone to turn it up before bed when the heating is off and the water is programmed to come on in the early morning before I wake up. 

tacpot12

Ally_E. said:

I have a system boiler and turn the flow temperature up when it's heating water and then down for central heating. I have an alarm on my phone to turn it up before bed when the heating is off and the water is programmed to come on in the early morning before I wake up. 

What is the make and model of boiler you have? There might be a way to automate the setting for different flow temperatures for heating water vs. central heating. 

FreeBear

ariarnia said: you don't need the boiler to be constantly above 60 do you? i thought i read on here some people turned it up one day a week to kill anything off. so you could still save vs keeping it at 60 all the time.

Legionella is a very, very small risk in the UK (some 250 cases reported annually). Having an open storage tank exposed to the elements increases the risk slightly. But water being fed directly from the main supply carries virtually no risk - The water will have been treated by the supplier to ensure that no bacteria is in the supply and that the water is safe to drink without any further treatment.

A combi boiler being fed directly from mains water does not need to heat the water above 60°C - You can quite safely turn it down to 50°C. If you do have any concerns, a quick "burn" at 60°C once a week (or even a month) is sufficient.

ariarnia

FreeBear said:

ariarnia said: you don't need the boiler to be constantly above 60 do you? i thought i read on here some people turned it up one day a week to kill anything off. so you could still save vs keeping it at 60 all the time.

Legionella is a very, very small risk in the UK (some 250 cases reported annually). Having an open storage tank exposed to the elements increases the risk slightly. But water being fed directly from the main supply carries virtually no risk - The water will have been treated by the supplier to ensure that no bacteria is in the supply and that the water is safe to drink without any further treatment.

A combi boiler being fed directly from mains water does not need to heat the water above 60°C - You can quite safely turn it down to 50°C. If you do have any concerns, a quick "burn" at 60°C once a week (or even a month) is sufficient.

i think you maybe misunderstood my post? i know all that and our combi is set to about 55 i think because we sometimes like hot showers.

but the OP has a water tank and was asking why the advice was to not have there water at lower temps. i was just saying they could have it lower and heat it hotter on a shedule to save some money. 

Joe9090

Thank you for all the replies.

Martin's email (as above) provided this link https://moneysavingboilerchallenge.com, which, when you go through the options, shows my boiler is not suitable for turning down the flow temperature.

As my boiler current flow temperature is 77°C and from what you have said I should have no problem turning it down to 60°C. Is that correct?

ariarnia

Joe9090 said:

Thank you for all the replies.

Martin's email (as above) provided this link https://moneysavingboilerchallenge.com, which, when you go through the options, shows my boiler is not suitable for turning down the flow temperature.

As my boiler current flow temperature is 77°C and from what you have said I should have no problem turning it down to 60°C. Is that correct?

i think 60-65 is recommended (i've actually seen a few places say it shouldn't be over 65 because they theres a risk of burning yourself if its not mixed with cold?).

but i think we are saying you could even turn it down to 55 and theres not much risk especially if you turn it up to 60 or 65 once a week to let it kill anything nasty that might have found its way in. but that its up to you as the recommendation is 60. 

here's a conversation from a few years ago where they were basically saying the same kind of thing https://forums.moneysavingexpert.com/discussion/5542822/hot-water-tank-temp

macman

The point of reducing the flow temp is to force the boiler to run in condensing mode more often, which is more efficient because it removes some of the heat loss via the flue gases: so it burns less gas.
Nothing to do with the temp of water in the hot tank in a non-combi system.