30kW System Boiler Choice

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My first (and never failed) technique for rad sizing was to think back to my student days: "how many bar heaters would I have used to heat a room?"
 
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DeltaT2

Δ T I am greatly reassured by your last post, the previous one made me think that you were so typical of our industry motivated by financial gain only with no real understanding of the technology..

now explain to me again please why you think compensation controls are a nonsense?

I never said WC was a nonsense, I said you're talking nonsense. I fully understand how WC works, have installed it a few times & a spend a few hours setting up the ratios etc.

The problem is that the Scotland is not like central Europe, we can have 4 seasons in one day during the heating season. Take for example yesterday, The Lady Puller put out a washing in the morning in glorious sunshine & a temperature of 14°C, By the afternoon we'd had rain, snow, high winds & a huge variety of temperatures. Now, to maintain an internal temperature of any reasonable level would be impossible!! Plus, Puller's Towers in a stone built building, it maintains a stable internal temperature in the Winter with a huge thermal mass of 600mm stone walls.

WC in Scotland is a nonsense, too many weather changes & a building or Central Heating system can't keep up! UFH & on/off controls are the only things that works.
 
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Alec, I don't know what you mean about WC technology 'not being readily available'.

Viessmann have offered it for years, since 1999 at least. We installed our first Vaillant one in 2004. They probably had it available before then.

Remeha have been offering it for years. Bosch/Buderus have had it for years. Worcester started offering it a few years back for the UK.

And of course, commercial boiler installations have had compensating controls for decades. I have pulled out Satchwell compensators with thermionic valves in the controllers, for example.

I can order a WC enabled domestic boiler with controls at 4pm from my merchants and it will be on site at 8am in the morning. That is not what I call 'not readily available'.


This is all a contrivance on your part to suggest that; 1. Weather Compensation is something new and 2. That you understand it better than everyone else.


Weather Compensation is just one of a heap of ways of reducing home energy consumption and it certainly doesn't deliver enough benefits to warrant your relentless self promotion on these pages.

Most customers we have put this stuff in for over the last 8 years have really struggled with the controls, and I don't think enough has been done by the manufacturers in this regard.

I know you say your customers understand it easily; but I think that is BS.

Many of my customers are intelligent people and they find it a pain to have to resort to a book each time they want to change a setting.

A book that in most cases, is full of pictures of suns, moons, hands, and clocks, and virtually no text. Why should customers have to read this carp?

There is nothing wrong with weather comp, but there is everything wrong with your shameless and relentless suggestions on this forum (and for all I know, other ones too) that it is the answer to everything. For many, if they took your vehement assertions as fact, it would be a huge disappointment and a millstone.
 
A

ALEC1

i am referring to the OT controls, which are not available in the UK, but generally available in europe..whch work just like on off controls..these do have implications on system design.

For what its worth for some people controls are complicated and is nothing to do with whether they are compensation controls...


I do find it interesting the lengths people go to to avoid adopting technology though
 
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ALEC1

honeywell... and compensated mixing valves for UFH for exampl

the fact of the matter is that modern condensing boilers have to accept compensation controls, and it is for good reason, they provide quantifiably better installations in terms of comfort, reliability and efficiency.


Its nonsense to invest in a boiler and to by pass its circuitry with the use of simple switches...why would any one do that?
 
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I fitted my first Opentherm on a Remeha boiler in 2007. Didn't have any problems sourcing the controls.

As Mr Hailsham has said before, modern boilers incorporate modulation and anti cycling technology, all reducing the impact of WC.

Sure, weather comp has its benefits, but they are not as great as you suggest because of the other measures in place in the boiler box.

Honeywell are the largest controls manufacturer in the World, they have plenty of WC technology. I have been advised they don't think there is a developed market for it in the UK at present, from either a customer demand or installer knowledge perspective.

When they do launch the controls they have talked about for general availability, I am sure they will be easier to use than the manufacturer specific ones.

The trouble is, although there is a standard in the form of Opentherm, it has been changed a few times, andin the meantime most of the leading boiler manufacturers have chosen to make their systems proprietary, such as eBus, KM bus etc.

So anyone considering investing in a launch of Opentherm controls in the UK is going to have a very restricted market.
 
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honeywell... and compensated mixing valves for UFH for exampl

the fact of the matter is that modern condensing boilers have to accept compensation controls, and it is for good reason, they provide quantifiably better installations in terms of comfort, reliability and efficiency.


Its nonsense to invest in a boiler and to by pass its circuitry with the use of simple switches...why would any one do that?

Basically what your saying is that you don't know how to wire up a Honeywell smile controller/compensator to a modern gas boiler because it doesn't have simple plug and socket connections provided by the manufacturer.
That would mean "work" wouldn't it?
Then you go on to say your plug and play system is more efficient.
Well it probably is! For your pocket.
:mrgreen:
 
A

ALEC1

its the availability and product information sharing that I have a problem with

Not the controls per se...


and yes i have installed the smile, and countless other variations...


The reason the subject is important and should discussed is because all heat generating appliances come with it..for a reason it must be...

Where I have upgraded controls from on-off the clients usually express dismay that so few people know about them,...
 
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the fact of the matter is that modern condensing boilers have to accept compensation controls.
That may be true in some continental countries, but since when has it been compulsory in the UK?

It's nonsense to invest in a boiler and to by pass its circuitry with the use of simple switches...why would any one do that?
Because they have no choice?

I had a new boiler Remeha installed two weeks ago; it was completely unexpected and not budgeted for. I thought about installing an iSense OT control, but this proved impossible without considerable upheaval - carpets and floors up to run cables etc. So I am stuck with my Honeywell CM927.

When the wireless version of iSense is available in the UK and someone make a wireless motorized valve, I will think again about OT.
 
A

ALEC1

all boilers sold in the EU have to have the compatability...but i suspect there are exceptions...


and yes there is a wireless i sense, but not in the UK....

and you client gets a lower spec heating system because some some one in an office doesnot understand the market....
 
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As Mr Hailsham has said before, modern boilers incorporate modulation and anti cycling technology, all reducing the impact of WC.
Can't ever remember saying that. I do remember commenting that most boilers do not modulate low enough. so they will spend much of their time in on-off mode.

Sure, weather comp has its benefits, but they are not as great as you suggest because of the other measures in place in the boiler box.
I wonder why weather comp is compulsory in Germany?

Honeywell ... don't think there is a developed market for it in the UK at present, from either a customer demand or installer knowledge perspective.
I think they have hit the nail on the head there. The vast majority of installers wouldn't know what you were talking about if you mentioned weather compensation. One guy I know thought I was talking about frost protection.

When they do launch the controls they have talked about for general availability, I am sure they will be easier to use than the manufacturer specific ones.
OT controls are not manufacture specific.

The trouble is, although there is a standard in the form of Opentherm, it has been changed a few times
But not significantly and later versions have always been backwards- compatible. So you can connect the latest OT boiler to a first generation OT controller and it will work, albeit to the abilities of the old controller.

Talking about Honeywell, I came across a document on the net about the new Wembley Stadium. Honeywell had the contract for:

the design, supply and installation of various electronic systems for communication and control of the building. These comprise nine separate systems as follows: 1. The building management system ("BMS"); 2. The fire detection and alarm system; 3. The public address and voice alarm; 4. The communications network; 5. The access system; 6. The stewards' and emergency telephones; 7. The MATV system; 8. The CCTV system; 9. The commissioning management systems. Most of these systems are selfexplanatory.

Item 1, the BMS, is a computerised control system for all the mechanical and electrical services such as heating, cooling, ventilation, in addition to the other Honeywell systems mentioned. The BMS control system is connected to 35,000 separate points throughout the stadium, each of which may have several individual control settings.


And people complain about the control system in a house, with one control point, being "complicated"?
 
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If you go back to page 1, you may recall throwing petrol on the fire yourself.

I'm happy to remind you, because you displayed a total lack of understanding of the basic tenets of heating a space. Perhaps you never did the mandatory 'energy efficiency' course for gas installers.

At the time we all complained about having to do it, but I guess they were trying to reach people like you who thought they knew better. Looks like we both wasted our time.
 
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You seem to think that a properly designed heating system will only achieve a 23 degree difference from out side temp to internal temp.
Are you seriously saying that last winter at minus 17 houses where only reaching 5 degrees inside or up in Aberdeen houses where not even getting above zero??
There is a considerable difference between heating a house from -17 to 21C and maintaining a temperature of 21C once the house is up to temperature. If the house had been stone cold at -17C the 15kW boiler would only be able to raise the temperature by 23C to 5C.

If the house is already up to 21c when the outside temperature falls from, say -2C to -17C, the house temperature will drop a few degrees. How much depends on the time that elapses and the construction of the house. If the house is allowed to drop 1C before the room thermostat turns the boiler on, then only 1/23 of 15kW will be required to bring the house back up to 21C.

If this wasn't the case the boiler would have to run continuously just to maintain an internal temperature of 21C when it was -2C outside. But no boiler does this; it only comes on occasionally to produce enough heat to maintain the temperature.
 
N

namsag

Now did you just make that all up or is it a collective of googling.
When heating is being designed one of the factors that is not included is when was the heating last on.
And why are you answering a question directed at simond or was it a mistake in logging in ?
 

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