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I had a new Atag 35+ Economiser fitted in May with an outdoor weather sensor and using the Atag Zone controller with it.

So far it's been doing what I expect and reducing the flow and return so that the boiler is condensing.

Now we're getting colder weather, I can't seem to get the house to be warm enough in the evenings so need some help please.

So far I have it set up to come on at 8am till 10am at 20 degrees ( controller is in the Hall so set lower so that main living room doesn't overheat) then 12 degrees from 10am till 4pm where it goes back to 20 degrees till 10pm then back down to 12 degrees till 8am. During the "off" times, the temperature will drop around 3 or 4 degrees at the moment.

What I've noticed so far is that the Atag Zone controller won't even reach 20 degrees - usually reaches around 19 degrees. Main living room has a temperature of around 20.5 degrees which is just a little too cool in the evening.

So how can I improve this? Am I doing something wrong, settings wise? The sensor is hard wired to the boiler but I also have Weather Compensation mode set on the Atag Zone controller - maybe this is wrong?
 
The hall stat is set lower than 20 C so the main living room doesn't overheat and yet the main living room is still too cool. What do you think?
 
Jem

I assume that your hot water is operating as expected. If so the issue centres on the way the external sensor has been installed and calibrated.


It is possible that the external sensor is not North facing and not always in the shade. It must be both to operate correctly. In simple terms, the sensor is demanding a boiler flow temperature that is too low to raise the room temp to 20 degrees. So the boiler runs for long periods with little effect. Normally after 20 minutes the boiler should override the external sensor - but again that depends on how it has been configured by the installer.

In these circumstances (sensor sighted incorrectly) it is recording a higher external temperature than ambient, consequently reducing the flow temperature lower than required.

Does that make sense?

The solution is :

Ensure that the sensor is properly sighted - it must never see the sun.

Ensure that it calibrated to the correct temperature curve to suit your lifestyle ( a job for the installer).

Occasionally, it is useful to have an override switch installed to deactivate the external sensor in early autumn and late spring - when it is warm outside, but still feels cold. I know that sounds illogical!!

It is a common problem where installers just fit the equipment without reading and fully understanding the instructions.
 
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Jem

I assume that your hot water is operating as expected. If so the issue centres on the way the external sensor has been installed and calibrated.

Yes hot water is fine.


It is possible that the external sensor is not North facing and not always in the shade.

It's NE and always in the shade. Temperature from the sensor says 9 degrees which corresponds with another thermometer I have outside to check.

Flow temp is currently 51 degrees and return flow 46 degrees. At the moment Atag Zone is showing 19.3 degrees having been on since around 8am.
 
If you are happy with the sensor position and temperature reading, then the temperature curve that the sensor is set to needs to be increased.

They are not clever devices ( external temperature sensors) . Control is a simple analogue curve in the boiler programming that sets a specific flow temperature against the specific recorded outside temperature. There are normally 5 or 6 curves to choose from.

In your case, the curve needs increasing to give you a higher flow temperature for the same outside temperature.

It is a 10 minute job for the installer to correct.

If you have any doubts about the above, turn the hall temperature controller up to 25 degrees - it wont make any difference to your sitting room temperature, because at 9 degrees the outside sensor is determining a boiler flow temperature that is too low to heat the emitters to the level of comfort your require.
 
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I have the same boiler I fitted it 2 years ago weather comp didn't work for us it was never warm enough the wife is always cold anyway , the one controller although having some good features has a mind of its own I couldn't live with it, so now have now installed a nest and haven't looked back my advice call atag technical support they can guide you through the ones settings some people will love the one me as a installer and atag owner it more trouble than it worth. Kop
 
If you are happy with the sensor position and temperature reading, then the temperature curve that the sensor is set to needs to be increased.

They are not clever devices ( external temperature sensors) . Control is a simple analogue curve in the boiler programming that sets a specific flow temperature against the specific recorded outside temperature. There are normally 5 or 6 curves to choose from.

In your case, the curve needs increasing to give you a higher flow temperature for the same outside temperature.

Thanks. I did notice the curves in the user manual. I'll take a further look.

If you have any doubts about the above, turn the hall temperature controller up to 25 degrees - it wont make any difference to your sitting room temperature, because at 9 degrees the outside sensor is determining a boiler flow temperature that is too low to heat the emitters to the level of comfort your require.

No I have no doubt about what you're saying and it makes sense. Thank you.
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I have the same boiler I fitted it 2 years ago weather comp didn't work for us it was never warm enough the wife is always cold anyway , the one controller although having some good features has a mind of its own I couldn't live with it, so now have now installed a nest and haven't looked back

I remember you telling me this back in May when I was asking about it. I'm happy enough with the actual controller and how it's working but I'd like the weather comp to work better for me. I'm not really a cold person but just need it a little higher.

my advice call atag technical support they can guide you through the ones settings some people will love the one me as a installer and atag owner it more trouble than it worth. Kop

Thanks. I will give them a call and see what they can do.
 
I am not familiar with your particular model of Atag boiler. However on other Atag models that I am familiar with, the parameter to adjust the “curve” is referred to in the Manufacturer’s Instructions (MI’s) as 2.4.9 External temperature correction (-3 to +3 degrees C).
 
The hall stat is set lower than 20 C so the main living room doesn't overheat and yet the main living room is still too cool. What do you think?

As the hall stat was never reaching 20 C, increasing it wouldn't have made any difference.
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Spot on, hopefully resetting the parameter will resolve your problem

Just to let you and everyone else know that I contacted Atag on Monday to get some help with this to make sure I was doing it right. Steffi was very helpful and had a look remotely at my settings on the Atag Zone controller. She then phoned me back and went over how to change it and explained the different possibilities and offered suggestions.

I have now chosen some different settings for insulation level ( it's a traditional sandstone building ) and size of house ( I'd gone for medium on initial set up but have decided on large now as my 3 bedroomed house is at least half as big again as my son's more modern 3 bedroom house). That has had the effect of raising the CH Flow temp to around 54 degrees C with a Return Temp of 48 degrees C at an outside temperature of 5 degrees C. Previously with a similar outdoor temperature the CH Flow temp was around 45-48 degrees C. The house now reaches the temperature set in the Hall stat and living room is comfortable.

I've set Room Influence to Less at the moment so it's about 70% weather and 30% room controlled. I may try More which is 50/50% just to see what difference it makes.

Thanks to you and King of Pipes for your help and setting me in the right direction.
 
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Glad you got to the settings you required jem it helps us to know we are being of service, atag are a premium product and I am sure you will be happy for years to come . Regards kop
 
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Jen,

They are referring to the difference between your flow and return temperatures - the delta should be higher. At the moment you still have too low a flow temperature to make any reasonable judgements in how well the system is balanced.

I would now wait for the weather to get much colder and then see how your system really performs.

Weather compensation is not at it’s best when you move into Autumn or out of Spring.
 
Jen,

They are referring to the difference between your flow and return temperatures - the delta should be higher. At the moment you still have too low a flow temperature to make any reasonable judgements in how well the system is balanced.

Ah ok - I'm with you now. What are you saying it should be then?

I would now wait for the weather to get much colder and then see how your system really performs.

Weather compensation is not at it’s best when you move into Autumn or out of Spring.

Ok I shall continue to monitor it.
 
I had a new Atag 35+ Economiser fitted in May with an outdoor weather sensor and using the Atag Zone controller with it.

So far it's been doing what I expect and reducing the flow and return so that the boiler is condensing.

Now we're getting colder weather, I can't seem to get the house to be warm enough in the evenings so need some help please.

So far I have it set up to come on at 8am till 10am at 20 degrees ( controller is in the Hall so set lower so that main living room doesn't overheat) then 12 degrees from 10am till 4pm where it goes back to 20 degrees till 10pm then back down to 12 degrees till 8am. During the "off" times, the temperature will drop around 3 or 4 degrees at the moment.

What I've noticed so far is that the Atag Zone controller won't even reach 20 degrees - usually reaches around 19 degrees. Main living room has a temperature of around 20.5 degrees which is just a little too cool in the evening.

So how can I improve this? Am I doing something wrong, settings wise? The sensor is hard wired to the boiler but I also have Weather Compensation mode set on the Atag Zone controller - maybe this is wrong?

Those boilers are hard work to set up, they have some sort of heating curve which sort of makes the room stat pointless.

Some Viessman boilers have the same system, but it's very technical and designed for homes that have multiple zones and different forms of heating.

I worked on a home in Derbyshire which had limecrete flooring with underfloor heating in one wing and radiants on the upper floors. The system was set up with a particular curve and weather compensation..... traditional room stats were not present.
 
Richard,

I think that you are confused. They have two very different functions.

The curve determines the flow temperature, not the room or zone temperature. It is within the control logic if the boiler ( or with Open Therm the controller).

Without a room or zone thermostat there would be no control to either call for heat or vice verse to the boiler.

There will almost certainly have been a thermostat (s) for the system you worked on.
 
Richard,

I think that you are confused. They have two very different functions.

The curve determines the flow temperature, not the room or zone temperature. It is within the control logic if the boiler ( or with Open Therm the controller).

Without a room or zone thermostat there would be no control to either call for heat or vice verse to the boiler.

There will almost certainly have been a thermostat (s) for the system you worked on.

Yes there is always a stat but because of weather compensation and the settings being used the boiler may not act in the way you would expect.

If there settings are wrong then you will find parts of the house very cold even though the boiler is on.

Its all down to how the boiler is set up, and that boiler is a very sophisticated bit of kit.
 
There is nothing overly complex with an Atag boiler - in fairness to Atag, they even publish the control logic - which it makes it very straight forward to trouble shoot unexpected behaviour. A few other boiler manufacturers could learn a lot from Atag.
 

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