Turn your boilers down to 60C to cut energy bills, households to be told

[Deleted User]

Legionella is just not really a thing to worry about in a domestic environment, unless you're doing something extreme or unusual.

Apodemus

Auti said:

 Do not understand the box under the boiler as no instructions on programming and so I use the hall thermostat to control boiler and the one hour boost hot water button (once a week as kettle used). Heat the house to 16/17 degrees - north facing rooms drop to 12/13 degrees overnight at moment but that will get worse  .   Any help gratefully received as to understanding controls as house takes ages to heat up and then it is time for school! 

Auti, you badly need to get an understanding of that box under the boiler. It is your programmer. The lower portion (below the line) should open forwards (hinged along the bottom) and give you access to all the controls for the timer settings for your heating and hot water. Much better for you to control it all by this, rather than just the wall thermostat.

I'm not sure which model of Danfoss programmer that is, but it won't be very different to the one here: http://www.free-instruction-manuals.com/pdf/p3133830.pdf

grn99

Unless it's condensing boiler I would run it at 70 so you're not spending ages with the house warming up slowly and use the timer control to set when heat can be called for in conjunction with the stat giving you your minimum preferred temp

I run my boiler  (flow temp 70) for an hr in the morning and from sunset to 22:00 in the evening. The room stat controls the boiler and is set to 18. Overnight it defaults to 10 degrees C for frost protection plus a bit of leeway. If there's no indication of your boiler's flow temps in the manual/on the boiler itself, I'd aim for 3/4 around the dial or use a temp probe on the flow pipe to gauge the setting.

I don't worry about the thermostatic radiator valves as they can skew things and I'd rather have a balanced heat through the fabric of the property. Personally, I don't believe that not heating one or two rooms is significant in cost terms and creates very different temperature zones in the property and any humidty will condense onto the coldest surfaces - potentially giving rise to mould and damp.

Follow-on thoughts.... If some radiators get hotter a lot quicker than others, or others never get warm your system may need balancing (using the lockshield on the radiators)...or there could be other issues.

ChesterDog

Auti said:

I am just getting more and more confused! Everything is turn down but then we get into realms of conflicting advice - hot water must be heated to 60 to kill legionella. Wash clothes in lowest temp but then not kill bacteria/viruses. Wash up dishes in cold temps but not kill bacteria/viruses. I have an Ideal Icos installed April 2006 with separate water tank (no immersion) in airing cupboard. Because of legionella I have turned up tank heating up to 60 degrees but am at a loss to understand what the markings on the dials mean on the boiler -photo below. The controls boxes are all from the previous boiler as are the trv‘s (that are now yellow with age). Do not understand the box under the boiler as no instructions on programming and so I use the hall thermostat to control boiler and the one hour boost hot water button (once a week as kettle used). Heat the house to 16/17 degrees - north facing rooms drop to 12/13 degrees overnight at moment but that will get worse  .   Any help gratefully received as to understanding controls as house takes ages to heat up and then it is time for school! 

I've a pdf of instructions for that controller, plus one for the boiler instructions. Message me if you'd like them.

Sterlingtimes

grn99 said:

Sterlingtimes said:

This is a headline from today's Daily Telegraph (behind a paywall).

Would this advice hold good for a heat-only (non-combi) condensing boiler?

We’ve got that problem on our heat only condensing boiler. It’s one thing to have a lower flow temp for the radiators but the same temp is used to heat the hot water cylinder.

I’ve found unless it’s at least 10 degrees hotter than the target cylinder thermostat it takes an eternity to heat it fully. So we compromise, with about 58 on the cyl and 68 on the boiler flow.

Reducing cyl temp is another option we tried, but then we used more of the cylinder water (less cold mixed at bath/shower)…. So if we do that then more water is used and the cylinder needs more water reheating sooner.

Thank you. This makes sense to me. My heat-only boiler appears to have a temperature adjustment for water (up to 60 degrees) and an adjustment for heating. I do not understand why they are separately adjustable. Anyway, the hot water cylinder works well at 55 degrees, so like you, my thought is to set the boiler at about 65 degrees,

grn99

Sterlingtimes said:

grn99 said:

Sterlingtimes said:

This is a headline from today's Daily Telegraph (behind a paywall).

Would this advice hold good for a heat-only (non-combi) condensing boiler?

We’ve got that problem on our heat only condensing boiler. It’s one thing to have a lower flow temp for the radiators but the same temp is used to heat the hot water cylinder.

I’ve found unless it’s at least 10 degrees hotter than the target cylinder thermostat it takes an eternity to heat it fully. So we compromise, with about 58 on the cyl and 68 on the boiler flow.

Reducing cyl temp is another option we tried, but then we used more of the cylinder water (less cold mixed at bath/shower)…. So if we do that then more water is used and the cylinder needs more water reheating sooner.

Thank you. This makes sense to me. My heat-only boiler appears to have a temperature adjustment for water (up to 60 degrees) and an adjustment for heating. I do not understand why they are separately adjustable. Anyway, the hot water cylinder works well at 55 degrees, so like you, my thought is to set the boiler at about 65 degrees,

If you have two separate adjustable controls on the boiler itself that's even better. You can set the hot water to 55 (as you have) as that works for you and the radiator heating temp can be whatever you choose. As it's a condensing boiler you could try and run it at 60 (or a bit lower) and see how it performs in warming up the house. That way you're more likely to get some energy saving as the return temperature (back at the boiler) needs to be 54 degrees C or below to condense. The lower the temp, the greater the savings in enegy use can be, but this has to be balanced with how long your house takes to warm up. Hope that makes sense. 

Sterlingtimes

grn99 said:

Sterlingtimes said:

grn99 said:

Sterlingtimes said:

This is a headline from today's Daily Telegraph (behind a paywall).

Would this advice hold good for a heat-only (non-combi) condensing boiler?

We’ve got that problem on our heat only condensing boiler. It’s one thing to have a lower flow temp for the radiators but the same temp is used to heat the hot water cylinder.

I’ve found unless it’s at least 10 degrees hotter than the target cylinder thermostat it takes an eternity to heat it fully. So we compromise, with about 58 on the cyl and 68 on the boiler flow.

Reducing cyl temp is another option we tried, but then we used more of the cylinder water (less cold mixed at bath/shower)…. So if we do that then more water is used and the cylinder needs more water reheating sooner.

Thank you. This makes sense to me. My heat-only boiler appears to have a temperature adjustment for water (up to 60 degrees) and an adjustment for heating. I do not understand why they are separately adjustable. Anyway, the hot water cylinder works well at 55 degrees, so like you, my thought is to set the boiler at about 65 degrees,

If you have two separate adjustable controls on the boiler itself that's even better. You can set the hot water to 55 (as you have) as that works for you and the radiator heating temp can be whatever you choose. As it's a condensing boiler you could try and run it at 60 (or a bit lower) and see how it performs in warming up the house. That way you're more likely to get some energy saving as the return temperature (back at the boiler) needs to be 54 degrees C or below to condense. The lower the temp, the greater the savings in enegy use can be, but this has to be balanced with how long your house takes to warm up. Hope that makes sense. 

Thank you, grn99. It was well worth posting here for this information. The complicating factor is that twelve of my radiator are controlled by intelligent thermostats, so there is a lot of on-ing and off-ing going on. I might experiment with 60 degrees. But I am at least convinced to go downing to 65.

brewerdave

All very well if you have a boiler which shows the flow temp. My 10 year old condensing boiler just has a temperature knob with no markings ! I've turned it down BUT had to wind it up again because a) her indoors said the radiators weren't warm enuf and b) the hot water was forever calling for heat. Tried to turn down the tank thermostat but it's stuck so need a replacement.

grn99

brewerdave said:

All very well if you have a boiler which shows the flow temp. My 10 year old condensing boiler just has a temperature knob with no markings ! I've turned it down BUT had to wind it up again because a) her indoors said the radiators weren't warm enuf and b) the hot water was forever calling for heat. Tried to turn down the tank thermostat but it's stuck so need a replacement.

Mine doesn't diplay actual flow temps, I purchased a contact probe to get the figures as these rotary controls on the boiler are estimates; probably +/- 5 degrees.

[Deleted User]

I have been running my system boiler at 55C for over a year. The key factor is that the temperature on the HW cylinder thermostat must be below 55C: if not, the boiler will just continue to run continuously. I am fortunate to have solar diversion. The immersion heater heats the cylinder up to 65C.

Running the boiler yesterday from 0645 to 2200 used 20kWh of gas. Clearly, your usage will also depend on your desired room temperatures. I have noticed no great difference in the time needed to get the house up to temperature.