Have you ever seen the maniold that supplies your 10mm, Ltnman?
Does it look anything like the photo?
It's not my manifold but I simply wonder what mine looks like. Mine serves both up and down and goes behind dot and dab, like yours.
Ideal Vogue combi. Range rating, or the lack of ......
- Thread starter Mr.B
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Have you ever seen the maniold that supplies your 10mm, Ltnman?
Does it look anything like the photo?
It's not my manifold but I simply wonder what mine looks like. Mine serves both up and down and goes behind dot and dab, like yours.
It runs at 70%’ can be increased to 100%. What more do you want? Delta t can be set at the radiators too. No point in having multiple options that will hardly ever be used. If one wants a bells and whistles set up, fit a low loss header and use Arduino to address the operation- gain will be hardly worth talking about.
Instead, fitting a multi zone smart TRVs will be way to go forward, even on a system that kept Adam warm when Eve had a hump
We'd have nothing to answer if you knew more
A three bed semi needs around 8kW.
If a combi try to find a boiler that can be range rated to what you need for the heating.
Look at the residual pump head for the boiler at 70%. In 15 and 22mm the head loss around a system is under 1.5m and for microbore unlikely to exceed 2m; if so then you're over-pumping and the delta T closes. You can strangle this at each radiator valve but better to have a pump that can modulate lower otherwise you're whipping the water out the boiler then trying to slow it through each rad.
Delta T pumps have limited use if you're modulating the flow temperature as you're reducing the starting point from which it operates.
Try for a boiler with adjustable anti-cycle delay as you can limit cycling and increase delta T that way.
Study the start up sequence in the manual, even if it's range rated many boilers still start at say 75% of the maximum output before modulating down. 75% of say 20kW is 15kW and the property needs only 8kW and that only when it's -3degrees, Most of the time it's definitely not -3. Try to find a boiler that starts at a percentage of it range rated output then has a timed ramp up.
Unfortunately this is the sort of post that leaves simpletons like me scratching their heads in despair.
Experienced installers might be familiar with low loss headers, Arduino and 'fitting a multiple zone smart TRVs' but it's not overly helpful after I said further back in the topic that new developments are leaving me behind.
I'm also confused when MNW67 speaks about not being able to turn the pump down but DP answers saying "it runs at 70%' can be increased to 100%".
I'm sorry but that hasn't helped much.
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Modern boilers are designed to work best when the difference in temperature (delta T or dT) between flow and return, at the boiler, is about 20C.
The faster the water flows, the smaller the dT.
There are two main things you can do to get the best dT. One is to balance/throttle the system by closing down the lockshield valves on the radiators. The other is to adjust the pump speed. And usually, I think, you would do both. In the old days pumps would have 3 speeds and the most appropriate would be chosen.
Some modern boilers with built in pumps (i.e. combi and system boilers) have a greater ability than others to vary the pump speed. The Ideal boilers have quite a simple system which is mainly automatic. It uses a fully modulating pump (i.e. continuously variable) and the speed of the pump varies depending on what output the boiler is currently modulating to. But on the Ideal boilers, the lowest speed the pump will ever go down to is 70%. So it will run at 100% when the boiler is giving 100% output. But say if the boiler is only giving 20% output, then the pump will still be running at 70% speed. The only other option you have on the Ideal boilers is to set it at 100% permanently. I would imagine the Ideal boilers work very well for the great majority of systems.
Many other boilers have a much greater range of options to vary the pump speed, which presumably gives more scope for fine tuning. Some Worcester Bosch boilers have a pump where you can set the maximum and minimum pump speeds, and in addition there are 6 other "constant pressure" modes to choose from. With some boiler brands, in addition to letting you set maximum and minimum, they let you set the pump so it varies its speed automatically to maintain the correct dT.
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We'd have nothing to answer if you knew more
A three bed semi needs around 8kW.
If a combi try to find a boiler that can be range rated to what you need for the heating.
Look at the residual pump head for the boiler at 70%. In 15 and 22mm the head loss around a system is under 1.5m and for microbore unlikely to exceed 2m; if so then you're over-pumping and the delta T closes. You can strangle this at each radiator valve but better to have a pump that can modulate lower otherwise you're whipping the water out the boiler then trying to slow it through each rad.
Delta T pumps have limited use if you're modulating the flow temperature as you're reducing the starting point from which it operates.
Try for a boiler with adjustable anti-cycle delay as you can limit cycling and increase delta T that way.
Study the start up sequence in the manual, even if it's range rated many boilers still start at say 75% of the maximum output before modulating down. 75% of say 20kW is 15kW and the property needs only 8kW and that only when it's -3degrees, Most of the time it's definitely not -3. Try to find a boiler that starts at a percentage of it range rated output then has a timed ramp up.
I've read through the above, Vulcan. Appreciate the time taken to try to advise. But, in the light of what I just said to DP, how is someone like me to go about selecting the boiler you have in mind given the advanced and specialist nature of what you've outlined - and please believe me, it IS advanced and specialist to me.
I say this having read lots of advisory posts on here discussing the how to choose the most suitable boiler and system and seeing that, as we well know, 10 installers will recommend 20 different alternatives it's not easy to pick the bones out of it and make sensible choices.
Vulcan, I know very well you work in the industry and are very experienced but you've assumed that I actually grasp the terms and phraseology in the post and have the ability to absorb it as readily as you are.How, realistically, do I source the information you advise? Ring the manufacturer? Study their literature? Ask a local installer? We both know it's not that simple.
I'm sorry to be negative but the older I get the less ability I seem to have to keep up.
I've understood what you've said there and am pleased you've posted it in legible terms, ta
The trouble is if, taking Worcester as an example, you come on here and are repeatedly given hugely conflicting advice about ownership of a WB boiler and that they leak, they're full of plastic, the aluminium HEXs rot and that RGIs find them difficult to work on etc etc etc. And then you get the polar opposite views that they're the Rolls Royce of boilers. You will have seen it all before.
And equally relevant, do the majority of installers I'm likely to encounter comprehensively understand these advanced features themselves? I'm not sure? And how does the average Joe find one that does?
So, in practice, how in the world is the man in the street to be advised in making sensible choices?
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Having looked at your starting post, why not buy a Tado Smart Control system and instal to your present boiler.
You will then still have present reliable boiler yet save on fuel used.
Do some research and specify the material. Installer will have his or her own preference but if you specify with confidence ( having familiarised yourself on how the system operates) then you will have the system you want. A good installer should know how to instal any boiler and effect repairs on it too. Fitting a boiler is not difficult, faulting it a different ballgame as is setting it up. Your present system is belt and braces ( boiler fails, hw heated with immersion heater), you loose this with a combi boiler. Viessman is a good product but components within can be a pain. I like ideal which lot of installers do not like.
System balancing is something you will be able to do yourself with help from these pages.
www.screwfix.com
You will then still have present reliable boiler yet save on fuel used.
Do some research and specify the material. Installer will have his or her own preference but if you specify with confidence ( having familiarised yourself on how the system operates) then you will have the system you want. A good installer should know how to instal any boiler and effect repairs on it too. Fitting a boiler is not difficult, faulting it a different ballgame as is setting it up. Your present system is belt and braces ( boiler fails, hw heated with immersion heater), you loose this with a combi boiler. Viessman is a good product but components within can be a pain. I like ideal which lot of installers do not like.
System balancing is something you will be able to do yourself with help from these pages.
Tado | Screwfix
Range of tado° products at Screwfix.com. Intelligent heating. Save energy. Reduce costs. Support the environment. App controlled. Ready for your call 24/7.
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All received. It's an option, DP.
I've read, and will re-read your post with interest.
Given my dilemma in trying to do the right thing I'm not gonna discount it.
Correct me if I'm wrong but did you not also recommend the same strategy earlier, but suggested Honeywell Evohome instead?
I acknowledge that Ideal's problems with Icos,Isar etc did them much harm and that Logic sumps and heat exchanger problems didn't help and that now they're apparently catching fire too but they're apparently popular and I thought the Vogue is quite well regarded on the whole. Does that summarise Ideal or am I wrong? I don't know how Ideal treat customers when it comes to service and warranty work though.
I've read, and will re-read your post with interest.
Given my dilemma in trying to do the right thing I'm not gonna discount it.
Correct me if I'm wrong but did you not also recommend the same strategy earlier, but suggested Honeywell Evohome instead?
I acknowledge that Ideal's problems with Icos,Isar etc did them much harm and that Logic sumps and heat exchanger problems didn't help and that now they're apparently catching fire too but they're apparently popular and I thought the Vogue is quite well regarded on the whole. Does that summarise Ideal or am I wrong? I don't know how Ideal treat customers when it comes to service and warranty work though.
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The issue is that boiler manufacturers produce installation and operation literature that is very sparse. I’ve been looking for detailed technical information on my boiler and there just isn’t anything beyond the basics.
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If looking at a Vaillant or Worcester boiler use manufacturer controls where possible.
They vary as well. The Alpha manuals are full of great info and are written in plain English in a conversational style. I found that a bit strange, with them being Italian and bearing in mind they sell comparatively few boilers here.
They give a great explanation about how to set up PDHW and weather compensation and about how the firing sequence and anti cycling works.
e.g.
My preference is Evohome which is more flexible to use
Ideal after service is very good. That is from personal experience as an installer and service engineer
In many cases boilers go on fire due to lack of proper service. Many companies and installers fail to carry service as detailed in the boiler manuals
You do have a point but I try to offer advice and answer a direct question and not simply name a boiler.
The advocates of other brands can answer your questions about their suggestions as they have the figures to hand otherwise it's just a model and brand that you have to research yourself in the dark.
How low is minimum modulation for heating?
What's the residual head of the pump at the boiler, can adjustment be made.
Can they post a pump graph from their manuals?
Is the anti-cycle delay adjustable?
What control options, modulating stat, single or dual temp weather comp?
Can it be range-rated in heating and does the boiler fire from max heating output or from range rated.
PDHW a possibility?
Is is a heavy heat exchanger with mass (why heat up a big lump of metal in addition to running a kitchen tap for a couple of minutes).
If they've had good service from the brand or is the unit easy to work on?
Large bore or small bore exchanger?
Things like that for each suggestion.