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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 947
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I installed a Gen 3 Nest. I have G=G, Y1=Y1, R=RH, W2-W2, -O

Customer Question

I installed a Gen 3 Nest. I have G=G, Y1=Y1, R=RH, W2-W2, B-O B, turned power on and nothing.
JA: I'll do all I can to help. Tell me a bit more about what's going on so we can help you best.
Customer: No power to the Nest.
JA: Is there anything else the HVAC Technician should be aware of?
Customer: It replaced a honeywell thermostat that the following wired: G, C, R, W! jumpered to Y, W2 umpered with E, and B.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the HVAC Technician about your situation and then connect you two.
Submitted: 1 year ago.
Category: HVAC
Expert:  Brian HVAC Guy replied 1 year ago.
Hi I'm Brian and I'm here to help! What did you do with the wire that was wired to the old Honeywell C terminal? Did you turn off power to your heat pump before starting the thermostat swap? Did your system run ok with the old thermostat?
Customer: replied 1 year ago.
I put C to C. It worked before I started but after I tried to go back to it and it did not work.
Customer: replied 1 year ago.
I turned off the breaker in my box marked heating and cooling
Expert:  Brian HVAC Guy replied 1 year ago.
Ok thanks for clarifying that, you didn't say and I wasn't sure and the Nest will normally work without a C connection. Offhand, the first thing I would look at is low voltage power. What type of heat pump do you have? Is it a split system with part outside and part inside? Do you know the brand?
Customer: replied 1 year ago.
It is a split system but I do not remember the brand.
Customer: replied 1 year ago.
I tried W1 to W1 before switching W1 to Y1 since they were jumpered in the honeywell system. I did notice that W1 was hot even after turning off the power
Expert:  Brian HVAC Guy replied 1 year ago.
Ok, thanks. My first thought is that you may have turned off the breaker for the outdoor unit because it would be normal for it to be labeled that way. If the separate breaker for the indoor unit was left on and at any point the wires from R and C touched, it would blow either a low voltage fuse or low voltage transformer in the indoor section. That is the very first place I would look. Most modern heat pump indoor sections have a fuse on the low voltage control board that uses a standard ATC3 automotive style fuse.
Customer: replied 1 year ago.
Okay I will need to check that in the morning since it is very hard to see at night. Thankfully we can get buy without the heat or A/C tonight. Any issues with leaving things still turned on?
Expert:  Brian HVAC Guy replied 1 year ago.
No, there should be no issue at all. I'll keep an eye out for your next post tomorrow.
Customer: replied 1 year ago.
Okay, the indoor unit is way under the crawl space in the front of the house. Very tough to get to it. I may need to have someone come in to look at it as I cannot make it under the house to that unit (too big).
Expert:  Brian HVAC Guy replied 1 year ago.
That's unfortunate when they're in a crawl space! Mine is under the house too but it's in a stairs down/duck and walk space fortunately! I'm 95% sure the blown fuse or transformer is your issue. The wiring you did should be right for your system so that's not the issue. Let me know if I can help further. If you're satisfied with your service with me, please remember to rate 3 stars or better before leaving! You can post follow ups here even after rating. Thanks for allowing me to help and thanks for using Just Answer! Best regards,-Brian