ATAG weather sensor/compensation

[dilalio]

My Atag ICE35 was playing up the other day - couldn't get heating to come on via the "one controller" so I disconnected the weather sensor and all was good. Put it back in today and it seems to be working.

How might I go about testing it? Are the parameters for ohms resistance documented anywhere. The MI's state mention 1Mohm in the legend, next to the terminals diagram but not sure how to test it for correct operation.
Have looked at a couple of YouTube vids regarding testing air temp sensors/thermistors for engines and reckon it's likely the same procedure, but???

Please and thank you's

 

[Steelmasons]

Test for resistance , simples.
Same deal when testing NTC/PTC thermistors.

 

[dilalio]

Test for resistance , simples.
Same deal when testing NTC/PTC thermistors.

Yes steel, but what should the parameters be? Can't find a reference to them!

 

[Steelmasons]

Possibly around 12k @ 20c.

 

[Dan Robinson]

@fatplumber will know more - but I assume its 1kΩ @25 degrees.... its not a 10 or 12K resistor on these IIRC.

What it goes up and down to I don't know, but easy an cheap enough to swap out - I thought i had one but was an intergas sensor which is 12K.

 

[bernardgreen]

This might help but you will still need to know from the manufactureres the exact type of thermistor.



As can be seen some have their base value at 0°C and others have base value at 25°C

 

[dilalio]

but was an intergas sensor which is 12K.

Bloody 'hell Dan... thought you said they were cheap!

 

[Dan Robinson]

 

[dilalio]

Right. Read up online and most thermistors are tested at room temp which is considered to be 25 degrees. Boiler thermistors usually in the range of 11-13,000 ohms at that temp.

Also found these in the ATAG manual...

So, what would the 1kOhm refer to above? The rating of the sensor?

And...

Looks like the column on the left show's temp/resistance of the outside sensor (T4). Can I measure this at the ends of the leads, at the boiler terminal block or do I have to get the sensor off the wall and test directly?

Thanks for your assistance guys.

 

[Dan Robinson]

You do it at the boiler end (unplugged from the boiler obvs) for the boiler is measuring the sensor and the cable run.

 

[dilalio]

Should study the table above myself really - before posting and asking

It's now obvious (as table states) that the weather sensor is 1kOhm and the other sensors are 10kOhm

Right... one controller reads that the outside temp is currently 14 degC so, if sensor is working correctly it should give a resistance of 1,555ohms

 

[Dan Robinson]

Yep - although its only 10 degrees here - mind you, you're a bit closer to Laaaaanndan than I am.

 

[fatplumber]

It's a nuisance that it's Intergas is different. I have loads of A series upside sensors.

 

[dilalio]

Ok, And I got 1,642ohms so the temp is dropping Dan

Now just makes me wonder why it was playing up the other day

I might have to give Leon a call and see if he has one 'on his van'

 

[Dan Robinson]

Could be an iffy connection on the sensor, but I don't think they're the most robust.... I sorted one out for Leon on an old E series a while ago that was doing the same thing - but the installation was a mess and it was screwing up the hot water too.