It's shocking so many so called CH engineers dont give this guidance. I got 6 so called 'gas safe' engineers round to quote for upgrading my 25 year old boiler to an new more efficient one and fitting TRVs. 3 suggested a combi to replace the heat only boiler despite the house being large having 4 beds, a bathroom, separate en suite with shower and 5 sinks. Of these 3 plus another 1 didnt bother sending me a quote. In the end, I had just 2 quotes to finally choose from.

Thanks for watching

Derek was only applying the principles to radiator systems!

@@johnward5006 check 9:32 again

@@UrbanPlumbers My point was, Derek was basing his presentation on a boiler as a heat source. As we all know, heat pumps are another scenario.

So in reality heat pumps are heaps of shite and not worth fitting in Scotland with some of the winters we have

@@mynameis9739 Very low ambient temperatures need to accounted for, particularly for heating water to 55-60c. Needs careful consideration.

The money i've saved on heating bills means that i've now got a 4 wheel drive - i went to the scrapyard,bought 4 wheels and put them in my drive....and i'm now driving around in a brand new TRV xx

Lol 😆 🤣 😂 😹

But then again it is currently -5°C, I wouldn't want my heating not getting to temperature at these not common, but occasional lows

To simplify Derek's post, as , for my sins I've been specifying and advising customers since 1972 when I went self employed, heat transfer and efficiencies are quite involved. From the end users perspective, insulate any pipes that get hot, only heat water( if you have a storage cylinder) to a temperature that you're happy with without adding cold water. Set the temperature of the water in the radiators to achieve , ideally, 20C or less, but in any case your comfort level. I always advised customers to dress in doors as you would outside. Take your overcoat off but keep your jumper on, not so difficult unless money's no object.

Slower warmup

Me too. What wold you change for say 23 deg room temp down and 21 up?

Put on another layer of clothes and make an effort to move a bit more. With the price of fuel we need to make 19 or 20 degrees work for us.

@@juliebrooke6099 I've got it on at a mere 15C to ward off damp, and a heated jacket lol

Jesus, mine never reaches 20 as I’ve got the flow down to 50 and don’t leave it on all day as even that’s too expensive. For 20 degrees it would cost me about £15 a day to run my heating even for ten hours, and I simply can’t afford to spend £450 a month on heating simply to be able to walk around the house without a jumper on. I’m currently spending about £6 to heat the whole house to a comfortable temperature that doesn’t have a chill for most of the day.

Will get a little over shoot Combi are often over sized to give you a good hot water flow rate . Wouldn't worry on the heating as that will modulate down anyway ,plus you have turned flow temperature down

At 48celsius flow, return comes at 26-28celsius

Boilers have thermostats inside of them to shut them down if they get too hot. Boilers are well designed from a safety point of view. The reason that condensing helps is that when the return temp is cold enough the vapour in the flue gas to condense on the pipes carrying the returning water. When something condensed the heat from the flue gas is passed to the return water coming back to be heated by the gas so it effectively needs less heat to make the outgoing water the set temperature. The following figures are made up so they are not accurate but will help. If your water is coming back at 40 deg and your flow temp beds to be 50 and it takes 1kw to raise the temp of the water by 1deg then your going to burn 10kw of gas. Now if you have condensing in the mix and that can add 5 deg to the water then you return temp water is 40 deg it goes into the condenser gets heated up by 5 deg and is now 45 deg, so to get it up to 50 deg flow temp you only need 5 kw of gas. Like I said made up numbers but hopefully that illustrates why condensing is good.

@@davideyres955 . Thank you for your reply, I understand the basics of what condescending is trying to achieve. My Worcester 30i was installed and left at the following flow temperature settings : Heating 75 c DHW 55 c I don't know whether this is factory settings or whether these temps were set by the installer. As I understand that condensing only affects the heating mode, is 75 c too high a flow temperature?. All rads get hot at much lower flow temperatures and following your advice on a KZfaq post, I've experimented and reduced the heating flow temperature to 65 c. I'm guessing that 75 c will waste gas ?. If I check the heating return temperature, what are the parameters for condensing, ie what is the minimum and maximum for efficiency?. Thanks.🤔

I used to have mine set at 4 at the beginning of Winter then up to 5 when frost was on the ground.

Because my boiler temp regardless of how much heat is being called for only reaches 62 even though the target flow temp is set to max of 75 for heating on my vailliant eco tech plus 832 combi I'm a woman BTW and want to make sure my boiler running sufficient as I had a normal boiler before with a cylinder and landlord changed it to a combi?

You could but your output would be less in those rooms with now undersized rads. Usually you wont need to replace all the radiators since your existing largest rads could be moved to the smallest rooms and then you'll only need to buy less new larger rads.

he uses BTUs so he must use imperial after that, otherwise the multiplication factors he applies in the formulas wont be accurate

@@gekypanathinaikos3879 well that's stating the obvious! I'm simply asking why ONLY use imperial. Watts are now widely used as well. That's how youngsters entering the trade are taught in college these days, and metric would have been taught to them in their schools.

@@tonyadams380 Hmm, yes I must admit in this day and age it seems strange that BTU's are still used. A lot of people claim metric units (kilograms for instance) are difficult to understand yet have no problem when they visit mainland Europe. Surely the profession should be pushing for the universal unit power and energy and using watts.

@@jesserawson898 It makes no sense at all when every other form of heating uses watts. BTW I'm 67 and have never used BTUs since school days!

@@chrisross1703 I remember my brother-in-law (an architect) still quoting heating in BTU's in the 1980's At college HND was in BTU's, to start with, then latterly changed to Watts. By implication BTU's are imperial whereas Watts are definitely universal so general adoption made sense. Also a BTU is an incredibly small unit for general commercial and industrial purposes. Mind you, so is a Watt, hence the use of kW . 🙂

Over heating the room

@@tomkatgastraining Huh??? Was that said with brain in neutral? 🙂

@@jesserawson898 no if rads are too big for the room the room will overheat

@@tomkatgastraining Ah, so TRV's are ineffective in shutting down the radiator in question. Hadn't realised that. Thanks.

@@jesserawson898 nothing to do with the TRVs it’s the heat held in the radiator and then released into the room

Below 55 degrees c

Happy new year! Thanks for replying! Being given the fact that after setting flow temp at 48celsius, when I measure the return water temp on the pipe which has installed the magnetic filter is below 28celsius..

Yeah 20 is OK if you're on the move a lot of the time - not warm enough if you're sitting in the evening.

Hi . Does it makes any change? Now I've just lowered mine to 48 Celsius as well ,as landlord installed an overpowered combi boiler of just "35kw" , at 52 Celsius flow set I got a reading of 55 when boiler works, I don't know if it's ok

Jury is out at the moment, house is fine but requires heating on for slightly longer.

It will take hours to come up to a comfortable temperature when it's really cold.

@@essanjay8604 , turned it up today to 55 with the incoming cold weather we are due.

TRVs act on air temperature not water temperature. They close when the room reaches the temperature set by the TRVs

TRV is an Open/Close switch working on a room temp sensor. When Open it will circulate whatever flow temp water is supplied by the boiler.

lol room is 30 but its colder at the bottom than it is at the top

May be their gas bill will encourage home owners to make the effort, it's only simple arithmetic at the end of the day.

Omg,those Tic tock brigade are better experts than any of us heating engineers.

I am a home owner and understand Delta T through watching KZfaq.

@@MrRawMonkey He said MOST not ALL homeowners! Clearly you have done research to understand this, unlike MOST homeowners.

That is so not true - I’m a 63 year old female that knew sweet “FA” about how to get the best out of my CH system but have learned a lot through watching these videos. Shame the CH Engineer who fitted my new system 18 months ago couldn’t be bothered to do all this for me or even balance the system following installation & I didn’t know enough to demand that he should

The 55 oc is heating not for the water

@@tomkatgastraining Most heat only cant give two flow temps ..

@@mgbroadsterJ exactly. So to avoid legionella the temp needs to be so high the bloody things don't condense.

Maybe check out how many people die or even contract Legionella before embarking on safetyism. About 50 per year, 20 of them got it from abroad, and less die from it. You are about as likely to die from lightning. maybe wear a Faraday cage everytime you go out? Encouraging people to emit more fumes and waste on money is overall worse than the negligible amount of people that could get Legionella (which incidentally starts dying even at 50c).

@@BarringtonDailey Legionella is also killed by the Chlorine or Chloramine they treat the water with. In a domestic environment where the hot water, shower etc is used on a regular basis the risk from Legionella is possibly vanishingly small irrespective of the hot water temperature.

Guess you didn’t watch the video then

That is the role of TRV’s surely