Aux heat not activating

[HeavenIsOrange]

We installed a heat pump with aux heat over the summer (York JHVTB24CBAC2N1A) along with a Nest thermostat in our upstairs.  I had the AC working fine with the hot weather, but it has become apparent in the recent cold spell that the electric heat strips are not kicking on.  When it got down near the 20F, the bedroom would get into to 55F during the defrost cycle.

I’m not sure if it is a setting in the app.  I’m also not confident on the wiring (and neither was the HVAC guy who installed it). I’ve got Y2, G, OB, W1, W2, C, R available at thermostat.

[luciaaa]

Hi, @HeavenIsOrange!

Thank you for reaching out to the community. I'm sorry to hear your heating system isn't working. I understand how important a functioning heating system is, especially in cold weather, and I'm happy to help.

I really appreciate the detailed information you shared. To troubleshoot effectively, please provide the following:

• What type of thermostat do you have?
• When did the heating last work?
• When was the last time you changed the furnace's air filter?
• Have you experienced extremely cold weather lately?
• Is it displaying any error code? 
• Do you have a schedule set? 

Since you have a heat pump system, the O/B wire might not be oriented correctly. I recommend checking the O/B wire orientation using this article: Change the O/B wire orientation.

The temperature might also be changing due to a Nest Renew subscription or enrollment in the Rush Hour program. Please check these possibilities using the provided links.

Please keep me updated. 

Best regards,

Ana

[HeavenIsOrange]

Nest 3 thermostat

heat pump was installed as part of attic conversion in the summer.  We are currently experiencing extremely cold weather for the first time this season (staying below freezing).  Heat and aux heat have worked.  Thermostat shows emergency heat but is duct work is not getting warm.

The filter was changed at three beginning of the month. No error code.

Temperature does not reach set point with or without schedule. I’ve tried switching O/B orientation and in B it only cools so switched back to O.

[luciaaa]

Hi, @HeavenIsOrange!

Thank you for your response. I appreciate the detailed information and your diligence in following the provided steps.

To better assist you, please tell me whether you have a single-fuel or dual-fuel system. A single-fuel system uses only one type of fuel for heating (e.g., electricity or natural gas), while a dual-fuel system uses two different fuel sources, typically an electric heat pump and a gas furnace. This information will help me determine if your thermostat is configured correctly, which may explain why the auxiliary heat (AUX) is not functioning properly.

To gather the necessary information, please share a photo of the following thermostat settings:

On the thermostat, select Settings > Equipment. Please share the configuration details for W1 and W2.

This information will help me provide more accurate guidance. Thank you for your cooperation. I look forward to your response.

Best regards, 

Ana