Ask Me Help Desk - Fuel Heat & Heat Pump both on!

:confused: My understanding is that the Heat Pump should not function while the Fuel Heat is on... thus avoiding dangerous gas pressure buildup for the compressor.
In my case, the Heat Pump remains on when the emergency heat supply turns on. The Yellow wire feeding the compressor relay remains hot (25 volts).
System: Goodman 3 ton, Oil Heat, Honeywell TH6110D T-Stat, Outdoor -12C kill switch (Power Rate increases below -12C). T-Stat's white wire feeds the oil burner NO Relay's coil(along with the common C wire). Yellow wire feeds the Heat Pump via a second relay's NC contact (this contact opens when the -12C kill switch closes to energize this relay's coil and simultaneously closing a NO contact sending the Yellow wire to the Oil Burner's relay coil where the White wire connects). Now why would the Yellow wire have to energize the Oil Burner's coil along with the White wire?. assuming the T-Stat is controlling the OIL Burner via the White wire? The T-Stat is on Heat mode (placed in Cool mode in summer).
I could not locate any info on how the T-Stat logic works... does it sense the compressor's On-Off condition via the Yellow wire?. does it simply parallel Emergency Heat (stage 2) to the compressor's heat supply (stage 1) i.e. both on, when the Heat Pump does not keep up with the heat demand?
Balance of T-Stat wires as follows: Orange to Heat Pump (cool).. Green to Furnace Fan relay.. and R to 25 volt supply (this supply feeds all: T-Stat, Heat Pump and the -12C kill switch).
To me this does not constitute a normal system set-up? Can it be improved?
Thank you

((My understanding is that the Heat Pump should not function while the Fuel Heat is on))

Yes you do not want the fuel heat as you call it to be running at the same time as the heat pump.

((In my case, the Heat Pump remains on when the emergency heat supply turns on.))

Not a good thing and you will have to fix that or call a qualified HVAC contractor to fix that for you.

I tried to read the rest of your question and the way it is written is very confusing. The questions and cures about wiring a fossil fuel kit or the thermostat to make this work needs to be done on site at your residence because there are to many circuits/low voltage landing points to try and remember here.

Here is what I suggest.

Read this

Product Application
This thermostat provides electronic control of 24 VAC single-stage heating and cooling
Systems, or 750 mV heating systems.

Then find it in your instructions that came with the thermostat.
Below is a link that will take you to the install directions for your thermostat just in case you lost them.

http://customer.honeywell.com/techli...0s/69-1714.pdf

Now go to the second screen down and you will READ where this thermostat is only good for one stage cooling and one stage heating.
Guess what. You have two stage heating and this thermostat will not work for you.

Next page down on the thermostat manual reads this.

Must be installed by a trained, experienced technician
• Read these instructions carefully. Failure to follow these instructions can damage
the product or cause a hazardous condition.
• Check the ratings in this booklet to verify that this product is suitable for your
application (see page 13).
• Always test for proper operation after installation (see page 9).

My final recommendation is for you to call a professional HVAC person.
Ask them to fix this major problem before YOU DAMAGE your equipment.
They will know the correct thermostat to use and they have the KNOWLEDGE to know how to hook it up correctly.

I just call them the way I see them. Good luck.

Quote:

Originally Posted by hvac1000

((My understanding is that the Heat Pump should not function while the Fuel Heat is on))

Yes you do not want the fuel heat as you call it to be running at the same time as the heat pump.

((In my case, the Heat Pump remains on when the emergency heat supply turns on.))

Not a good thing and you will have to fix that or call a qualified HVAC contractor to fix that for you.

I tried to read the rest of your question and the way it is written is very confusing. The questions and cures about wiring a fossil fuel kit or the thermostat to make this work needs to be done on site at your residence because there are to many circuits/low voltage landing points to try and remember here.

Here is what I suggest.

Read this

Product Application
This thermostat provides electronic control of 24 VAC single-stage heating and cooling
systems, or 750 mV heating systems.

Then find it in your instructions that came with the thermostat.
Below is a link that will take you to the install directions for your thermostat just in case you lost them.

http://customer.honeywell.com/techli...0s/69-1714.pdf

Now go to the second screen down and you will READ where this thermostat is only good for one stage cooling and one stage heating.
Guess what. You have two stage heating and this thermostat will not work for you.

Next page down on the thermostat manual reads this.

Must be installed by a trained, experienced technician
• Read these instructions carefully. Failure to follow these instructions can damage
the product or cause a hazardous condition.
• Check the ratings in this booklet to verify that this product is suitable for your
application (see page 13).
• Always test for proper operation after installation (see page 9).

My final recommendation is for you to call a professional HVAC person.
Ask them to fix this major problem before YOU DAMAGE your equipment.
They will know the correct thermostat to use and they have the KNOWLEDGE to know how to hook it up correctly.

I just call them the way I see them. Good luck.

My error in calling the system a 2 stage heat source... when I have Heat Pump + Emergency Heat + Cool modes.
I attach sketch of T-Stat & interposing relays setup which hopefully clarifies above description of system connections (see T-Stat setup1.jpg). These are as setup by the Heat Pump/T-Stat Supplier/Installer.
Can you please comment and recommend any changes?
Thank you

((My error in calling the system a 2 stage heat source... when I have Heat Pump + Emergency Heat + Cool modes))

Hello
First stage of heat is the heat pump
Second stage of heat id the emergency heat.

You have TWO stages of heat and a one stage heat thermostat.

W is for the change over valve in the outside heat pump not for a oil burner.
Please see page 5 in the link I posted. This from Honeywell. It does not show or state that you can use this for a heat pump in combination with any other furnace or emergency heat. Your thermostat will not work.

Yes sir you do have a two stage heat system.

Now tell me you are a engineer or something because they are the only ones who try and make something work when it is not designed to.

Please re read the link I posted to you.

Quote:

Originally Posted by hvac1000

((My error in calling the system a 2 stage heat source...when I have Heat Pump + Emergency Heat + Cool modes))

Hello
First stage of heat is the heat pump
Second stage of heat id the emergency heat.

You have TWO stages of heat and a one stage heat thermostat.

W is for the change over valve in the outside heat pump not for a oil burner.
Please see page 5 in the link I posted. This from Honeywell. It does not show or state that you can use this for a heat pump in combination with any other furnace or emergency heat. Your thermostat will not work.

Yes sir you do have a two stage heat system.

Now tell me you are a engineer or something because they are the only ones who try and make something work when it is not designed to.

Please re read the link I posted to you.

LOL.. yes I ARE one, but I had nothing to do with the installation...
Thanks for confirming my doubts.. will try to convince the installer that they goofed up!
Will later post the correction.

Problem resolved. Contractor replaced thermostat with Totaline Model P286-1500 and setup for 1 Stage Cooling/ 2 Stage Heat. The O/B/W goes to HP Changeover Valve, Y1 to HP Comressor and W2 to Oil Furnace. This results with HP being off it's heating cycle while Oil Furnace is on. Let me know if this appears to be a poor setup even if it works.
Thank you.

Good deal glad you got it going.