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Why is there only an electric emergency heat option and not oil/gas also?

r2d2c3p0
Community Member

Why is there only an electric emergency heat option and not oil/gas also?

15 REPLIES 15

CoolingWizard
Silver Product Expert
Silver Product Expert

If your system is a Heat Pump and you want to have and alternative heating system you must choose dual fuel heating as part of the set up. It is fully possible and I have set up many systems that way. If you need professional help to set it up, seek a Nest Pro support to come reconfigure your thermostat. 

Ken, The AC Cooling Wizard

NestPro and HVAC company owner

Thanks for the reply. I wired this tstat identically to the Honeywell T6 and verified the 'pro' settings on it. All was working correctly. I set the nest up as dual fuel and the only option under pro settings on the nest is electric emergency. See screenshot. 

 

Capture.JPG

CoolingWizard
Silver Product Expert
Silver Product Expert

I see your Alternative Heat is set as Oil. So you have a boiler hydronic system? The boiler heats water and routs the hit water to radiators? 

NestPro and HVAC company owner

I have duel fuel / hybrid. Oil furnace forced air and heat pump using same blower.

Oil should function in 3 scenarios.

1. When temp outside is below set point for efficiency on the heat pump.

2. When I call for 2+ degrees of heat. T6 understood this fine.

3. Emergency heat.

CoolingWizard
Silver Product Expert
Silver Product Expert

Here’s how to understand what that snap shot is showing you. Your stage one or primary heat says electric, that’s telling you that the heat pump is the primary motive heat. Heat pumps run on electricity that’s it’s called electric. The alternate heat is going to be the oil furnace. And the third or emergency heat is also electric heat strips that are in your air handler that were installed probably when the heat pump is installed.

Ken, The AC Cooling Wizard 

NestPro and HVAC company owner

 

The Nest thinking Emergency heat is electric is incorrect. I worked with the HVAC company to spec the new system and was here for the installation of the new HVAC system and walked through everything with the installers including how/why the wiring to the T6 was setup the way it was. 

The system is heat pump / oil burner, that's all. 

 

 

 

CoolingWizard
Silver Product Expert
Silver Product Expert

So you are saying your T6 was not programmed with Emergency electric heat? On the T6 the emergency heat type is not specified in the programming of a T6 you just simply specify that you have emergency heat and it will be activated when switching emergency heat on. In other words the wire attached to the E terminal will be energized.  If the emergency heat is not specified why is there a control wire for it? What is the energy type and source for the emergency heat? If your HVAC company set up with Oil Burner as the alternative heat, and double wired the oil burner to the emergency heat, what was the system design goal? 

The current set up of your Nest thermostat will indeed perform everything that T6 was doing and more. Specifically if you set the heat pump to come on as primary heat and the heat pump begins to lose efficiency due to the low ambient outdoor temperature, the nest will turn on the oil burner as supplemental heat. It will also do this if the temperature setpoint and the room temperature are greater than 3°F. If indeed the oil burner is wired to both auxiliary heat and emergency heat, you have the same configuration in the Nest.  You can activate emergency heat and you will get the oil burner heat. Your entire problem seems to be with the fact that the screen reports your emergency heat as electric and not oil, this complaint despite the function is working, it seems to me that you just want the nest to display oil for emergency heat is that correct?
This T6 thermostat you seem to be in love with, does not tell the consumer what the emergency heat source is. In fact, why would the consumer care?  Your T6 is option programmed that for emergency heat, energize the wire attached to E terminal. For emergency heat, the Nest will activate the same wire that is plugged into the *.  Again, functionally the same. So, if it functions the same, what is the problem? Simply the summary page that shows “electric” in the emergency heat type?  

Overall we follow the HVAC industry standards in design of systems that are heat pump-based. You don’t typically design a system where the emergency heat and the auxiliary heat are the same system. Think about it, if the heat pump switches off at say 35°F outdoor ambient temperature, the auxiliary  heat is activated. If the auxiliary heat cannot keep up with the demand load, what are you gonna turn on as a supplement heat booster, answer, emergency heat. Well if the emergency heat is the same oil burner system, then you don’t really have any emergency heat. What do you have is simply a dual fuel system where number one is heat pump electric and number two is oil burner furnace. Basically the HVAC industry would set up a heat pump system the way yours is, whenever you don’t want the consumer to have to be concerned about the HVAC system when the heat pump fails, the system would just be placed in emergency mode and the emergency heat would be activated. That’s all the consumer needed to know if your heats not keeping up or your primary heat system is broken , simply turn on emergency heat and call for service repair. 

So, was it you or your significant other that wanted to replace the T6 with the Nest Leaning Thermostat 3rd Generation? The T6 does not have a touch screen, and does not even have a filter reminder. The T6 screen is monochromatic and is not as aesthetically pleasing.  The Nest Learning Thermostat that comes in four ring colors; stainless steel, black, white or copper. The nest thermostat has improved sensors for sensing when you’re near it so it knows you’re there and it wakes up displays the current temperature, the T6, it just stays on all the time. The nest learning thermostat third generation has a smaller and slicker design than the T6 old school square shape. The Nest can be paired with a remote temperature sensor if you desire to have to control a specific different room that is remote from the thermostat. The T6, not an option for that. The Nest Thermostat  can use internal temperature sensors and can use the Internet for exterior temperatures in your area. The T6, sorry not an option.  You can add an external temperature probe and wire it to the T6 though.  In fact, if you want the T6 to turn off the heat pump at say 35°F, you have to install the remote outdoor temperature sensor. Otherwise it will not know how to do that or when to switch to the oil burner. 

I am sorry for the long reply but basically you did not make a mistake switching to the nest learning thermostat third generation.

Ken, The AC Cooling Wizard

 

 

NestPro and HVAC company owner

No the T6 was programmed correctly for E heat. T6 could do the following correctly as above.

 

1. When temp outside is below set point for efficiency on the heat pump switch to oil burner.

2. When I call for 2+ degrees of heat switch to oil burner.

3. Emergency heat switch on oil burner

 

CoolingWizard
Silver Product Expert
Silver Product Expert

Functionally, what is the nest not doing that you think the T6 can do. Putting a list of things up there is not functional it’s simply a list. Does the nest have the ability to turn on the emergency heat, yes. Can the Nest turn on auxiliary heat when the temperature difference between indoor and setpoint is greater than  2°F degrees, yes.  Can the Nest turn on the auxiliary heat when the outdoor ambient temperature falls below 35°F, yes. Again, I don’t understand what the specific problem you’re having. Functionally it is the same. OK so it says electric and doesn’t say oil. But functionally neither does the T6. In fact the T6 does not show you the wire configuration now does it? The T6 does not give you a summary of your system now does it?

Agin, WHAT IS THE SPECIFIC PROBLEM THE NEST IS NOT DOING?

NestPro and HVAC company owner

I am sorry for the long reply but basically you did not make a mistake switching to the nest learning thermostat third generation.  I don't think so yet.

 

This T6 thermostat you seem to be in love with - Not sure where you inferred that. My point was it worked minus the remote app which is what I want. 

 

It seems to me that you just want the nest to display oil for emergency heat is that correct? Displaying correct information vs. incorrect is always helpful...so yes it should display what is there or option to select it. It's misleading otherwise.

 

Specifically if you set the heat pump to come on as primary heat and the heat pump begins to lose efficiency due to the low ambient outdoor temperature, the nest will turn on the oil burner as supplemental heat. It will also do this if the temperature setpoint and the room temperature are greater than 3°F. -  How is this enabled?

Agin, WHAT IS THE SPECIFIC PROBLEM THE NEST IS NOT DOING?

Drop the CAPS - I think I explained it before. You are taking too many tangents. 

I'll return it at this point. 

 

 

 

CoolingWizard
Silver Product Expert
Silver Product Expert

@r2d2c3p0 wrote:

I am sorry for the long reply but basically you did not make a mistake switching to the nest learning thermostat third generation.  I don't think so yet.

 

This T6 thermostat you seem to be in love with - Not sure where you inferred that. My point was it worked minus the remote app which is what I want. 
the remote access is definitely a nice feature to have. 

 

It seems to me that you just want the nest to display oil for emergency heat is that correct? Displaying correct information vs. incorrect is always helpful...so yes it should display what is there or option to select it. It's misleading otherwise.


Unfortunately the  information is based on “industry norms” so it is typical that the “emergency heat” is electric heat coils when a heat pump is the system.  Yes, there are unique systems and the the Nest is performing just right, it simply displays electric when you are using Oil. Functionally, it is working fine.  Perhaps you can submit a product feature request 

 

Specifically if you set the heat pump to come on as primary heat and the heat pump begins to lose efficiency due to the low ambient outdoor temperature, the nest will turn on the oil burner as supplemental heat. It will also do this if the temperature setpoint and the room temperature are greater than 3°F. -  How is this enabled?

it is already enabled when you set the 35°F to switch over. 


 

NestPro and HVAC company owner

Jeran
Community Specialist
Community Specialist

Thank you for helping out on this thread, CoolingWizard!

Hey there r2d2c3p0,

I'm just checking up on this thread, do you have any more questions or need any additional help?

Best regards,
Jeran

r2d2c3p0
Community Member

Hi Jeran,

I returned the nest and bought a honeywell T6 Pro wifi. It works.

Jeran
Community Specialist
Community Specialist

Hey there r2d2c3p0,

No problem at all. If another device works better for your current situation, that's totally fine. In that case, I'll go ahead and lock the thread. If you have any more questions or concerns in the future, please feel free to create a new thread.

Best regards,

Jeran