Weather compensation sensors

[JLS]

I've picked up a Worcester Fw100 programmer for a new boiler install but it didn't come with a weather compensation sensor, are all sensors equal or will I have to source a Worcester sensor for it to work? If so is there a specific one I need to get? TIA

 

[ShaunCorbs]

It should come with one best phone up your supplier and get them to send you one

 

[kris]

Defo best to stick to Worcester sensors although open therm is open therm ,

 

[heatservice]

Defo best to stick to Worcester sensors although open therm is open therm ,

Open therm is not Open therm as WB boilers are not compatable with NEST so Im hearing.

 

[JLS]

Thanks all for the input, unfortunately it was bought cheap off ebay. Still live and learn.

 

[Gasmk1]

only cost about £30

 

[Old Account]

Open therm is not Open therm as WB boilers are not compatable with NEST so Im hearing.

oh is that true nest isnt compatible with wb boilers in general?

 

[heatservice]

oh is that true nest isnt compatible with wb boilers in general?

Apparently, NEST will work OK as a wireless /internet control for WB boilers but is not compatible when it comes to open therm, the part that is required by Boiler Plus.

 

[S.P.S.]

When you say the open therm part is the bit required by boiler plus, where have you read that? All I have read is that it must be a smart control woth automation and optimisation.

My understanding of this is - the ability to learn/adapt to weather/usage.

I haven’t read anything about the smart control having to control the flow temperature by way of load compensation.

I’m just intruiged to see if I’ve got it right or miss interpreted something, that’s all!

Thanks

Stu

 

[heatservice]

Have a look at PB Plumber video on YouTube "What is Boiler Plus ?" (sorry I couldn't post the link with my Smart tv)

 

[doitmyself]

It's all in the latest edition of the Domestic Building Services Compliance Guide. See pages 16 & 21.

 

[S.P.S.]

So I was correct in my thinking? Opentherm is not a requirement.
Open therm is a way to encorporate load compensation on compatible boilers.
IE controls flow temperature based on the demand.

Optimisation and automation are just ways to reduce the amount of time and the buildings temperature based on external factors, such as occupancy and usage. IE a learning thermostat like NEST or HIVE.
But this doesn’t mean it has to directly control the flow temperature of the boiler based on demand, just reducing when it fires to a more effience use.

Unless I am reading all this wrong?

Again, I’m an only looking for clarification on how I perceive it. If I am wrong on this, can you explain how?

Thanks in advance.

Stu

 

[heatservice]

Im glad to be retired from it all, looks like your being asked to walk through a mine field wearing a blindfold with your fingers in your ears for good measure, good luck with that.

 

[doitmyself]

are all sensors equal

You have to have the correct sensor. The working component in a sensor is a Negative Temperature Coefficient resistor (NTC), i.e. a device whose resistance increases as the temperature decreases. Manufacturers do not all use a NTC with the same resistance/temperature curve so you are normally stuck with the manufacturer's product - unless you can find out which NTC they use and can obtain one from another source.

 

[Welder]

Specifically, one of the correct resistance (IIRC 100 ohms) but in the reqd temperature range as linear response as possible. None are truly linear tho.

Tis a strange deal this. A requirement to fit controls, but they are of little value when the homeowner has no inkling how or why they work. Then you factor in the inescapable fact that few installers understand them either and you end up, potentially, using more energy...

IMHO, it would have made far more sense to have made it mandatory for all installers to understand controls and then to have incentivised them to educate users. It woudl have been slower but it would be a solid foundation of knowledge and professionalism as opposed to the current box ticking fiasco...

Hey ho, welcome to an enlightened UK...

 

[doitmyself]

Specifically, one of the correct resistance (IIRC 100 ohms) but in the reqd temperature range as linear response as possible. None are truly linear tho.

Never heard of 100 ohms. 5k, 10k, and 12k (ohms), yes.

Boiler makers tend to keep this info to themselves - so you have to buy their product at inflated prices?

I agree that installers need to understand the benefits of modern controls. (I asked one well-established installer what he thought of weather compensation. He thought I was taking about frost protection.)

 

[Welder]

Didn't think I was that bad... You made me check
Farnell's (where I buy most of my electronic components) have 'em in the range 47 ohms to 100k including 100 ohms.

Old but not quite written off yet...

I am intrigued. What do YOU understand by weather compensation?

 

[doitmyself]

Yes, NTC thermistors are available in a wide range of values and tolerances. As you say, the temperature/resistance curve is not exactly linear. I did read that it is possible to make it linear, but can't remember how. May be the boiler mfr does this within the PCB.

As far as I am concerned, weather compensation is a method of varying the flow temperature in inverse proportion to the outside temperature; i. e the colder it gets, the higher the temperature. The reason for doing this is that the heat required to maintain a certain temperature in the house is directly proportional to the difference between inside and outside temperatures, so radiator output needs to vary. As the output of radiator varies with water temperature, it is logical to use this fact to obtain the required output.

Incidentally, TRVs work much better if weather comp is used.

 

[Welder]

Yaa. Someone clued up...

A vital element of compensation is the rate of heat loss. This differs from building to building and is also directly impacted by weather. Specifically wind (strength and direction) and local temp. The true rate of loss can only be measured via embedded sensors i. e. embedded in the building fabric.

Unfortunately, today we assume weather based on internet data and have removed embedded sensors. This leaves, at best, vauge approximations of conditions and reduces potential savings by 10 %.

Shame todays designers a) dont actually understand how things worksand b) place undue reliance on inaccurate and approximate data.

Its called progress...

 

[S.P.S.]

Tradition, the enemy of progress!

I have been guilty of this in the past, the trouble with being trained by a very old school plumber....

Stu

 

[Welder]

Or physics and doing the job properly...

The two points of controls are A) to deliver improved comfort conditions and B) to reduce energy consumption. Less effective, less efficient processes (i.e. negating vital contributory factors) deliver neither. Therefore current methods cannot constitute progress no matter how its re-labeled because it's less efficient outcome actively harms our planet.

If people wish to label that desire to get it right - 'old school' then they are both sadly lacking in intelligence as well as understanding of our Earthly plight.

Neither our children and or childrens' children will look back and thank us for this greedy laziness. Instead we will be labelled the generations that put profit before lives... What a legacy!

 

[ShaunCorbs]

Or physics and doing the job properly...

The two points of controls are A) to deliver improved comfort conditions and B) to reduce energy consumption. Less effective, less efficient processes (i.e. negating vital contributory factors) deliver neither. Therefore current methods cannot constitute progress no matter how its re-labeled because it's less efficient outcome actively harms our planet.

If people wish to label that desire to get it right - 'old school' then they are both sadly lacking in intelligence as well as understanding of our Earthly plight.

Neither our children and or childrens' children will look back and thank us for this greedy laziness. Instead we will be labelled the generations that put profit before lives... What a legacy!

What about people who can't afford to have anything fancy and have to go with a cheap boiler

 

[Welder]

Even simple controls set up correctly and explained properly can save significant amounts and provide reasonable comfort