Hi, Jamie here from the video. You can set your hot water on a combi boiler to whatever you want in my opinion. I always went 50 degrees. What it actually achieve will vary depending on the time of year too. Hope this helps

@@We-Are-FlowState Many thanks for the reply. I have the heating flow down to 60 degrees now and maintain the DHW at 45 which is fine

The bar isn’t as important for efficiency but a recommended range of between 1 and 1.5 when cold is good but not the end of the world if it goes slightly higher. For hot water it depends if you have a hot water tank or not. If you don’t then 50 degrees is a good temperature to aim for. Hope this helps 😊

🎉🎉🎉🎉 congratulations - you win absolutely nothing but the pride of being the 100th comment 😊

Flow is the temperature you set at the boiler, the return temperature (some boilers show) is when the water has been round all the open (on) radiators and returned back to your boiler (obviously it's at a lower temperature as heat has been given off to the room(s). Condensing boilers actually condense at 54C but the lower return temperature the more efficient the boiler is. Bear in mind that in the really cold weather, at too low a flow temperature, it may not be hot enough to satisfy the target (room) temperature. As a (very) general guide, anything below -1 outside would benefit from a flow of around 60-70C, and generally Spring/Autumn temperatures the flow can be anything from around 50 -60C.

@@johnw2758 I don't think anybody boiler actually says flow and return. My boiler has a temp for a tap and a temp for the radiators. What should each one be?

@@anonanonanonanonanonagain Most boilers show the flow (radiator) temperature and you can sometimes press a button to see the return temperature. There are 2 icons for setting the flow, a radiator and a tap icon. The radiator icon is the flow temperature for the radiators, this time of year 60C is a good general temperature for that (if it's a condensing boiler), if it's not then I think the general rule is to set this to max (80C etc). The tap icon is for altering the temperature of the water that comes out of your taps. Obviously you don't want it scalding hot and by adding cold water to get a good (say bath) temperature is countertuitive, therefore a lower temperature is ideal. We have our radiator flow about 56C (this is all dependant on outside temp and how well insulated your house is), and our tap temperature at 48C. This allows us to fill a sink or have a shower without adding too much cold water.

I think it's max

Hi Julian, It depends what sort of system you have, do you have a Combi boiler or hot water tank?

@@jamie-theheatingguy4870 Thanks for your helpful posts here. can i ask some relevant questions please ?. i have a WB 30i condensing boiler, 2 years old, full TRV's and ESi "open therm" ? mobile CH thermostat, . No HW tank or boiler driven shower. At fitting, boiler CH flow was set at 75c and HW at 55c. All works fine but i'm guessing not economical. Following your advice to save cost, i have now reset the heating to 65c and may try even lower. Some you tube posts mention that boilers won't condense if flow temperatures are set too high, but don't explain or give temperatures. One engineer says his CH flow is set at 30c, so at 75c, i'm guessing i'm wasting money. I wrongly assumed a boiler would condense at all its designed operating temperatures. What are the min and max temperatures for both heating and HW ( i assume individually), for the boiler to work efficiently ?. Secondly, some engineers post that if flow temperatures are too low, there is a risk of legionnaires disease. Is this only a risk with stored water, ie, a hot water tank, or in all situations ?. It seems there is more to flow settings than simply cutting the gas bill. Please advise, thanks. 😁

@@julianhowarth1075 if you don’t have a hot water tank then no need to worry about legionella, the boiler overrides all this. I have my hot water set to 50 degrees, it might not condense but this is expected in hot water. Just be mor le mindful about not wasting the hot water that’s produced. The required flow temperature varies according to the outside temperature. The cold it is, the hotter your flow temp would need to be. If it’s too low then you’ll waste energy by not heating the room quick enough. Too high and it won’t condense, so there is some wastage there. It also depends on the design of the heating system and your radiator sizes in relation to your rooms- lots to consider. So with all that in mind, there is no perfect temperature, but if I installed a boiler I would typically set it to between 55 and 65 and see how it goes. In the depths of winter 55 might be too low but I would just see how my house feels and how it reacts to the heat. Sounds like you’re on the right track. Hope this helps

Hey! I have same boiler, so yes you can! There is a school of thought that you lower the flow temperature of the heating system but leave it running longer... This is better for the system apparently because its not cycling on and off and also can save gas because its not having to do regular blasts of heat. Or something 😆 We're not long into a new house with a different system, and yesterday I just put the system on manual all day (and night) at 20° and the house was evenly heated and used the same amount of gas as I have evert other day when I've had it on a timer (4 hrs morning, 5 hrs evening). I had to turn the heat down in the two rooms aye with the controller thermostat so that it took longer to heat up which allowed the other rooms to heat nicely and let the TRV on the radiator control the room. Have a look at Heat Geeks channel, some good info there too

What about do you have Johnny? Do you the make and model?

Hi Anonanon, depends on what controller you have installed but chances are you will need to do this manually 😊

@@jamiecureton2898 Thank you Jamie. Its a manual operation on my boiler. I will though take your advice when the weather, if it does, drop to very low single figures. Thanks!

That is correct. The reason for the recommendation of 55 degrees is so that the heat being emitted the radiators during warmer months is a much nicer temperature. Otherwise the heat curve of the property will all over the place.

I have a Vaillant condensing boiler, radiators, external temperature sensor. The house is well insulated too.. But whatever heat curve I sett the radiator water goes always over 50-55 Is there a way to limit the temperature? I don't expect negative 20c° outside.. The curve is now at 0.90.. Can I sett something beside the heating curve? I've watched this one, but it's for vitodens kzbin.info/www/bejne/qnyWaXqvfbmmmLs

@@luckystrike656 yea on the Vaillant you can set a max flow temperature. You’ll need to go into the settings by following the procedure in the manual and from there you can set the max flow temp. I’ll be honest, I’m not on the tools any more so I can’t remember exactly how to do it for all boilers, but for different Vaillant’s there is a different procedure so make sure you read the book. Thanks

@@luckystrike656 you should be able to limit the maximum flow temperature in the settings. Sounds like your heat curve set too high or your weather comp ain't set up right.

It seems like cooler temp will make the boiler run constantly (or at least very frequently). Is that ok? And is that most efficient?

1. On some boilers depending on the version of opentherm they are working to, the opentherm can tell the boiler to modulate the pump at burner on/burner off. Our ideal Vogue runs the pump at high when the burner goes off and then modulates the pump lower when the burner is on. 2. The opentherm controller will tell the boiler what flow temperature it wants, the boiler then modulates via it’s internal safety circuits the burners to achieve that flow temp. 3. Weather compensation is different in that it utilises the outside air temperature and you set a linear heat curve e.g at 0c outside your flow temp would be 60c but at 15c outside your flow temp would be 25c. The thermostat will just tell the boiler what it wants and the boiler will adjust it’s output… I’ve tried both and I prefer opentherm as it’s based on the actual internal conditions the greater the diff between set point and actual temp the harder the boiler works.

Correct as there is more surface area.

The numbers could from 30 to 80, try the middle value

Hi NRG, there are controls available that allow the system to have 2 different temperature for heating and hot water. Heating will be set for condensing and hot water will be max for rapid re heat. It then only allows either heating or hot water to be used at separate times. But other than that your point is valid 😊

I guess you don't care about your energy bill either...

@@DavidTheScientist he will because it is tangible.

You probably also think the earth is flat, the moon is made of cheese, and mankind is only 6000 yrs old.

@@georgejetson4378 so childish. There's ample Proxi data showing that 7000 ppm CO2 was the norm during the most diverse period of flora and fauna explosion on earth.

@@georgejetson4378 I don't think he'll believe in things that have imperical evidence to the contrary. The CO2 debate is quite tenuous when you apply the scientific method, unfortunately though its the new religion and people get upset when their new god is questioned...hence your banal remarks. I'd suggest rather than jumping to the defence of the extraction of wealth from the poor racket, you actually go off and apply the scientific method to some proper research.(ovoid the BBC).

I think it's flow temperature that people are referring to here. And there shouldn't be a need to make such smaller adjustments normally - the boiler would just run longer when the outside temperature is lower, in order to reach the desired warmth (set by your thermostat). For instance set the boiler's flow temperature to 50 degrees C and forget it - if there is insufficient insulation in the property or the radiators are small etc then you can set flow to 55 and that should be it.

Get a thermostat with opentherm capacity (Honeywell Lyric does this) and make sure your boiler can do opentherm. It’s plug and play. I prefer opentherm to outside weather compensation.

Well said...

No. Your system will lose at least 10c by the time water returns. Just make sure your rads are properly balanced. But set temp as low as possible for max efficiency

55 FOR CH. 43 FOR HW.

@@esecallum my radiators are luke warm all the time. I think I need to bump it up to 70C as we have -5c outside and the hallway thermostat never gets above 17c and even that takes all day to reach from 14c. I find it all so confusing.

⁠​⁠​⁠​⁠@@esecallumno he is talking about a system boiler not a combi. I suspect He has a hot water tank that has to be heated above 55deg to kill off legionella. The temp of the heating is whatever will get your house to a comfortable temperature with the minimum of cycling (on off on off etc) with the right controls the boiler will turn down it’s power to try to match the temperature output with the heat loss. The lower the temperature the boiler runs at the more condensing it does and the more latent heat from the gas combustion gets used. You are correct with a combi since you are heating the water through the boiler on the way to the hot tap. No point in running up to 55 and having to mix it with cold at the tap. If you heat a hot water cylinder at 43 then you risk legionnaires disease.

@@davideyres955 really? how come none of had legionaires after 20 years of above tempd...its a scare thing.

The Urban Plumbers recommend intergas. I''ve a new navien. It's many levels above the previous Bosch I had

Ha ha ha good luck getting that differential across a radiator. No chance.

Just checked mine and flow going out is 58oc and coming back in at 54oc and that is going into the boiler settings showing flow and return

@@gaeryfleming172 so you have a 4 degree differential.

Yes 4oc is that OK

3 downstairs radiators are fully open and bedroom ones upstair are on half way

They have prob changed the circuit board and not put the dials in the correct place.

@@magicgsuk6312 absolutely correct. I’ve just checked it and you’re absolutely correct. Thank you.

I’ve sent me sort code and account number over😂

Very Funny :)