Heat Meter Calibration - Sontex 449

Hi All,

I’ve recently had some work done to my system following a previous discussion on this forum with my system that was showing low COP

I’ve had primaries upgraded, the buffer removed and antifreeze valves / glycol removed.

Early indications look positive (still an issue with low flow rate - but I’ll pick up that separately).

My heat meter (Sontex 449) is calibrated for glycol. I wondered if anyone could advise on two things:

  1. What will be there error rate on the energy calculations now - will my reported COP be inflated / artificially increased?
  2. Can anyone advise on recalibration of the heat meter in situ, or does this need to be a new meter (hence I wanted to understand the error).

Many thanks in advance and please let me know if my question isn’t clear.

Thanks in advance

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You can set the working fluid back to pure water using the software and a USB optical eye.

Buy / beg / borrow / steal something like this to connect to the meter:

I can ping you a copy of the programming software by email if you send that to me by PM

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Will do! Thanks for the quick response - I’ll PM you, I’m not technical at all so may need some advice.

What will be the effect on accuracy of COP at the moment? Can you advise / guide?


You’ll have to ask the OEM for support or likely errors. I don’t supply these meters; but happy to share the software if you want to self serve. :slight_smile:

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Hi all,

Thanks for your input to this. Just in case it’s useful for others - DMS (UK contact for Sontex) have advised that for the Sontex 449 I can send the physical unit (not plumbed part the flow meter) back to DMS in the post and they are able to reprogram the unit to adjust for the removal of glycol.

They have quoted £25 plus return postage. Which is cost effective against the cost of a lead as kindly suggested by @markocoheat - which is another option if people are more technically minded and skilled than I am!

I thought this may be helpful for the future.

I’ll keep you updated.



Just to close this off. Heat meter was returned, and shipped back the following day recalibrated.

I found it easy to wire back up (battery version) and it’s reporting data again!

DMS Metering offered a great service, and sent a certificate to confirm compliance for OFGEM if I need it in the future.