EMS ECON wire Connection

[Sohot]

i Currently have Brivis GAS wombat 120 ems and my old thermostat unit is connect to R ,W and EC which is connected to main board R,W and EC(ECON which is for high low fan) G(Cool) and T(24v) are currently not used
Just would like to know if i decide to purchase the nest what do i connect the EC(Econ) wire to on nest unit. is it w1

[Markjosephp]

Hello Sohot,

Thanks for reaching out to the Google Nest Community Forum.

It appears to be that you have a Proprietary system and not Nest compatible. But to be sure, could you please share your old thermostat's wiring?

I'll look forward to your response.

Regards,
Mark

[Sohot]

Thanking you greatly for reply. i have watched a few YouTube videos and have same unit and they have managed to connect an get it working but they are not using EMS ECON connection which is just a high low setting Economy mode. Its just a switch as diagram states . when R and EC are bridged it goes from low fan/GAS to high. also i do not need c wire as i have 24volts from unit to charge unit.

https://www.youtube.com/watch?v=-MptX7Hou7k

Also Ecobee was also connected to same unit

https://www.youtube.com/watch?v=p0Fc1L9HTg0

sorry upside down

[CoolingWizard · Accepted solution]

Your Brivis Wombat is basically a 2-wire gas heater with a somewhat proprietary control system.  The Power is sent to G, W, ECON, and the R is the ground or Common.   This power configuration is not compatible with any conventional HVAC control system thermostat.  

AC Cooling Wizard.

[Sohot]

i have decided to not purchase nest Thermostat. my decision has come to no response to  my earlier discussion regarding wiring of unit. i was looking forward to purchasing but if customer service is lacking greatly. time for another unit. i may have to pay more but i do not  care as long as it works.

[CoolingWizard]

@Sohot , the Nest Thermostat comes with everything you need to wire up your system.  In fact Nest provides an online compatibility checker that you can access and is easily found with a Google search.   Here the link to save you time. 
https://store.google.com/widget/compatibility/thermostat

You need to only follow step by step process and input your Wires attached to your current thermostat.  The compatibility checker will verify that it’s compatible and even recommend which thermostats models work for your system.

AC Cooling Wizard

[Sohot]

i know that it is compatible as i have seen YouTube video with it working on same unit. it just the  Econ low economy mode that is not listed. i have tried chat line at nest customer service and it is on waiting on line for hours on end and dos not move forward and have given up on that.

you can see connection diagram at below link at previous discussion

https://www.googlenestcommunity.com/t5/Nest-Thermostats/EMS-ECON-wire-Connection/m-p/438702#M94751

[Markjosephp]

Hello everyone,

@Sohot, I've duplicated your thread in the main one here. You’ll receive all updates on this issue on the main thread, and we recommend updating and checking this thread when needed.

Thanks for looking into this, @CoolingWizard.

Best regards,

Mark

[Jenelyn_O]

Hi folks,

I appreciate your help, Mark and @CoolingWizard,

I hope you got the answer you're looking for. Please let us know if you still have questions in mind.

Best,

Jenelyn

[Sohot]

the answer i got was not exactly what i was looking for as i think it will operate with my unit as i have looked into with some research . I was told on this community Your Brivis Wombat is basically a 2-wire gas heater with a somewhat proprietary control system that i have which is correct but the unit does have 24 v compatibility and has worked on my brivis unit using nest thermostat and Ecobee thermostate as stated on atached video links. its just the high econ mode that i need to know to connect to . the Brivis 529 Analog Interface module can be used  for the EMS/MPS Heater but for new units but as my unit is older it is not needed .
The system operates as a two stage heater, Economy and Full rate. The two stages are controlled by calling for heat on the W1 and W2 terminals

[Sohot]

https://www.youtube.com/watch?v=l1Mzr46iZ_4 This video explained evertyhing for 2 stage heating it looks like w2 is uses for 2 stage heating ECON(EC) to W2 on thermostat