Nest E on multi fan relay

Jul 9th, 2018 8:30 pm

#1

marktang [OP]: Deal Addict; Jan 31, 2006; 4748 posts; 829 upvotes; Toronto

Jul 9th, 2018 8:30 pm

My thermostat is crapping out on me so i am thinking of switching to those smart thermostats. Nest E seems like a good deal but the thermostats i have uses G,G2,G3 fan but Nest E only seems to support G. Is it possible just to wire the G2 into the Nest E and have medium fan only? And will it auto stop when it reaches a certain temp if i only have one G wire wired. Thanks.

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Jul 10th, 2018 12:26 am

#2

thriftshopper: Deal Addict; Jul 7, 2017; 2979 posts; 1155 upvotes; SW corner of the cou…

Jul 10th, 2018 12:26 am

Looks like the 3rd generation Nest will support multi-speed fans if the firmware is updated.

https://nest.com/support/pro/article/In ... -fan-wires

Almost too cheap to shop through RFD

Jul 10th, 2018 7:52 am

#3

bubuski: Deal Addict; May 23, 2009; 2235 posts; 773 upvotes; Mississauga

Jul 10th, 2018 7:52 am

You can try the Nest e and see how it works with only one G-wire (g2 that you want). Some hvac units require a specific g-wire (highest speed which is g3 in your case) or the hvac won’t power on.

Jul 10th, 2018 8:59 am

#4

marktang [OP]: Deal Addict; Jan 31, 2006; 4748 posts; 829 upvotes; Toronto

Jul 10th, 2018 8:59 am

bubuski wrote: ↑ You can try the Nest e and see how it works with only one G-wire (g2 that you want). Some hvac units require a specific g-wire (highest speed which is g3 in your case) or the hvac won’t power on.

i have a R wire, i think that's the power wire isn't it?

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Jul 10th, 2018 8:34 pm

#5

bubuski: Deal Addict; May 23, 2009; 2235 posts; 773 upvotes; Mississauga

Jul 10th, 2018 8:34 pm

marktang wrote: ↑ i have a R wire, i think that's the power wire isn't it?

Yes R is power but it won’t matter if your hvac is designed to look for continuity on a specific G wire.

Jul 10th, 2018 9:16 pm

#6

marktang [OP]: Deal Addict; Jan 31, 2006; 4748 posts; 829 upvotes; Toronto

Jul 10th, 2018 9:16 pm

bubuski wrote: ↑ Yes R is power but it won’t matter if your hvac is designed to look for continuity on a specific G wire.

oh i know what you mean now. Maybe i should pay more and get the 3rd gen then.

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Jul 10th, 2018 9:55 pm

#7

bubuski: Deal Addict; May 23, 2009; 2235 posts; 773 upvotes; Mississauga

Jul 10th, 2018 9:55 pm

What thermostat do you currently have? Might be possible as a test to disconnect and cap your g1 and g3 then monitor how it works. If no other issue apart from the missing fan speeds then you should be good to swap it out for a nest e.