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#1
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heat pump/secondary propane furnace questions
I have a lot to ask her but thought it's worth a shot. It has to do with
the house not heating well. Last August we moved into a single family home (2 years old), which has a number of heating/cooling systems. The upper floor has a heat pump, presumably in the attic. When we had the home inspected I followed the guy into the attic where he pointed out the unit. My assumption is that this unit handles the heating/cooling of the 2nd story. It has a thermostat in the master bedroom and appears to work fine when the outside temp is above 20 degrees or so. I'm not worried about this system. The main floor and basement are handled by several systems, and it's here I have questions. There are two units outside, one of which appears to be a dedicated air conditioner and a second unit that's a heat pump. We also have propane furnace/air handler. These units were controlled by a mercury-based manual thermostat, but I replaced it with a Honeywell RTH7400D programmable thermostat using the same wires (4 wires: g,w,y,r). For what it's worth, the propane also provides the heated water and a gas fireplace. Here are the questions: 1. Is the heat pump the primary heat source and the propane secondary, or the opposite? The inspection report calls the propane the primary source, but that doesn't seem right, and the seasonal contractor we had inspect the unit recently said the propane "appeared" to be the secondary. If it's not all that cold outside, the heat pump is on, but not the propane, for example. Today, at 16 degrees, both units run. And struggles to maintain 70. 2. The thermostat required a setup before programming the 7 days of the week. One of the steps was choosing the heating/cooling system. There are 10 choices: - heating and cooling (conventional) - single stage heat pump with no backup or auxilliary heat - heat only with no fan (conventional) - heat only with fan (conventional) - hot water heat only (conventional) - Cool only (conventional) - multistage heat pumps - multistage conventional heating and cooling (2 stages heat and 2 stages cool: requires w/w2 and y/y2 wires) - multistage conventional heating and cooling (2 stages of heat and 1 stage cool) - multistage conventional heating and cooling (1 stage heat and 2 stages of cool) Right now I have it on the first setting. 3. What are the "stages" regarding heating systems as referred to above? My assumption is that a heat pump with emergency/auxilliary heat is a multistage heat pump (like the one in our attic for the second floor) but does it also refer to a secondary heating source like natural gas, oil or propane? If I had a W2 wire I suspect the 9th choice would be the most appropriate but I just had the 4 wires mentioned above. After calling Honeywell, the person agreed that the first choice seemed the most appropriate. 4. I have heard twice now that heat pump/propane heat systems work just fine if you leave the temperature constant throughout the day/week, but have trouble with "recovery" when you let it dip in the evening and try to reheat in the morning when everyone rises. This seems to be the problem with these systems and programmable thermostats. Today I programmed every day and every "event" to the same temp to see if this pans out over the next few days. I AM going to get the HVAC contractor out here again, at my expense, to pick his brain in person, since I wasn't at home when he did the initial inspection for us. However, any insight to the above beforehand would be of great help. Thanks in advance. John |
#2
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"JohnW" wrote in message
... The upper floor has a heat pump, presumably in the attic. When we had the home inspected I followed the guy into the attic where he pointed out the unit. My assumption is that this unit handles the heating/cooling of the 2nd story. It has a thermostat in the master bedroom and appears to work fine when the outside temp is above 20 degrees or so. I'm not worried about this system. A heat pump is just a reverse-cycle air conditioner. In your case it the air handler is in the attic - but the compressor for the AC / heat pump is outside. There are two units outside, one of which appears to be a dedicated air conditioner and a second unit that's a heat pump. Nope, they are both condensers, used in conjunction with your inside air handlers. Likely one or both are also capable of reverse cycle (a heat pump). We also have propane furnace/air handler. These units were controlled by a mercury-based manual thermostat, but I replaced it with a Honeywell RTH7400D programmable thermostat using the same wires (4 wires: g,w,y,r). For what it's worth, the propane also provides the heated water and a gas fireplace. G - Fan W - Heat (1st stage) Y - Cool (1st stage) R - Power Here are the questions: 1. Is the heat pump the primary heat source and the propane secondary, or the opposite? The inspection report calls the propane the primary source, but that doesn't seem right, and the seasonal contractor we had inspect the unit recently said the propane "appeared" to be the secondary. If it's not all that cold outside, the heat pump is on, but not the propane, for example. Today, at 16 degrees, both units run. And struggles to maintain 70. Most commonly the heat pump is primary (1st stage) and the propane would be secondary (2nd stage). Are you sure the old thermostat didn't have another wire for second stage heat? It could be that the furnance controller handles calling for the 2nd stage, but that is unusual. 2. The thermostat required a setup before programming the 7 days of the week. One of the steps was choosing the heating/cooling system. There are 10 choices: - heating and cooling (conventional) - single stage heat pump with no backup or auxilliary heat - heat only with no fan (conventional) - heat only with fan (conventional) - hot water heat only (conventional) - Cool only (conventional) - multistage heat pumps - multistage conventional heating and cooling (2 stages heat and 2 stages cool: requires w/w2 and y/y2 wires) - multistage conventional heating and cooling (2 stages of heat and 1 stage cool) - multistage conventional heating and cooling (1 stage heat and 2 stages of cool) Right now I have it on the first setting. Makes sense with only four wires. Are you SURE there wasn't a fifth wire? 3. What are the "stages" regarding heating systems as referred to above? My assumption is that a heat pump with emergency/auxilliary heat is a multistage heat pump (like the one in our attic for the second floor) but does it also refer to a secondary heating source like natural gas, oil or propane? If I had a W2 wire I suspect the 9th choice would be the most appropriate but I just had the 4 wires mentioned above. After calling Honeywell, the person agreed that the first choice seemed the most appropriate. If you have aux / emergency heat strips then it is a 2-stage heat system (NOT a multistage heat pump, which is a different animal). Of course you COULD have both a multistage heat pump AND aux / emergency heat, but that is uncommon. 4. I have heard twice now that heat pump/propane heat systems work just fine if you leave the temperature constant throughout the day/week, but have trouble with "recovery" when you let it dip in the evening and try to reheat in the morning when everyone rises. This seems to be the problem with these systems and programmable thermostats. Today I programmed every day and every "event" to the same temp to see if this pans out over the next few days. Ignore what you are hearing. ANY setback saves energy. Google for more information on this widely misunderstood topic. I AM going to get the HVAC contractor out here again, at my expense, to pick his brain in person, since I wasn't at home when he did the initial inspection for us. However, any insight to the above beforehand would be of great help. Thanks in advance. Good idea. |
#3
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Travis, thanks so much for your response.
After reading through it, I trudged back out in the snow to look at both outside units. They both, are indeed, heat pumps for both cooling. You know what they say about "assume". However, if this is the case, the one unit I had assumed was a/c only HAS NEVER come on for heating since installing the programmable thermostat. I also looked at the old manual thermostat and there is no LED indicator that lights up when aux or Emergency heat is on: note however, there is on the manual thermostat that is in the upstairs bedroom. I also pulled the front piece of the programmable thermostat and looked at the wires again. The old thermostat only had 4 wires attached (g, y, w, r--trust me, I actually took notes while doing this--but I noticed a blue and black wire coiled up in the wall. I guarantee these were not connected when I did the swap. As an experiment, I put the face plate back on and pulled up the thermostat's setup menu where the heating/cooling system is to be selected and again browsed through the choices (note I've added details for the 7th item in parenthesis as written in the manual): 1 heating and cooling (conventional) 2 single stage heat pump with no backup or auxilliary heat 3 heat only with no fan (conventional) 4 heat only with fan (conventional) 5 hot water heat only (conventional) 6 Cool only (conventional) 7 multistage heat pumps (heat pump with auxilliary or backup heat) 8 multistage conventional heating and cooling (2 stages heat and 2 stages cool: requires w/w2 and y/y2 wires) 9 multistage conventional heating and cooling (2 stages of heat and 1 stage cool) 10 multistage conventional heating and cooling (1 stage heat and 2 stages of cool) I changed the setting from 1 to 7 and the other heat pump can on immediately! It cycles off and on periodically as it maintains 70 degrees. However, now the propane shut off, which always seemed to be running before. I assume it's safe to keep the setting on 7, and I should check this after sundown and tomorrow morning and see if the propane is coming on to supplement the heat pump. I'm still going to get a service tech out here to double check everything, but the setup as we had it couldn't be right. Live and learn. Thanks again, Travis... John "Travis Jordan" wrote in message ... "JohnW" wrote in message ... The upper floor has a heat pump, presumably in the attic. When we had the home inspected I followed the guy into the attic where he pointed out the unit. My assumption is that this unit handles the heating/cooling of the 2nd story. It has a thermostat in the master bedroom and appears to work fine when the outside temp is above 20 degrees or so. I'm not worried about this system. A heat pump is just a reverse-cycle air conditioner. In your case it the air handler is in the attic - but the compressor for the AC / heat pump is outside. There are two units outside, one of which appears to be a dedicated air conditioner and a second unit that's a heat pump. Nope, they are both condensers, used in conjunction with your inside air handlers. Likely one or both are also capable of reverse cycle (a heat pump). We also have propane furnace/air handler. These units were controlled by a mercury-based manual thermostat, but I replaced it with a Honeywell RTH7400D programmable thermostat using the same wires (4 wires: g,w,y,r). For what it's worth, the propane also provides the heated water and a gas fireplace. G - Fan W - Heat (1st stage) Y - Cool (1st stage) R - Power Here are the questions: 1. Is the heat pump the primary heat source and the propane secondary, or the opposite? The inspection report calls the propane the primary source, but that doesn't seem right, and the seasonal contractor we had inspect the unit recently said the propane "appeared" to be the secondary. If it's not all that cold outside, the heat pump is on, but not the propane, for example. Today, at 16 degrees, both units run. And struggles to maintain 70. Most commonly the heat pump is primary (1st stage) and the propane would be secondary (2nd stage). Are you sure the old thermostat didn't have another wire for second stage heat? It could be that the furnance controller handles calling for the 2nd stage, but that is unusual. 2. The thermostat required a setup before programming the 7 days of the week. One of the steps was choosing the heating/cooling system. There are 10 choices: - heating and cooling (conventional) - single stage heat pump with no backup or auxilliary heat - heat only with no fan (conventional) - heat only with fan (conventional) - hot water heat only (conventional) - Cool only (conventional) - multistage heat pumps - multistage conventional heating and cooling (2 stages heat and 2 stages cool: requires w/w2 and y/y2 wires) - multistage conventional heating and cooling (2 stages of heat and 1 stage cool) - multistage conventional heating and cooling (1 stage heat and 2 stages of cool) Right now I have it on the first setting. Makes sense with only four wires. Are you SURE there wasn't a fifth wire? 3. What are the "stages" regarding heating systems as referred to above? My assumption is that a heat pump with emergency/auxilliary heat is a multistage heat pump (like the one in our attic for the second floor) but does it also refer to a secondary heating source like natural gas, oil or propane? If I had a W2 wire I suspect the 9th choice would be the most appropriate but I just had the 4 wires mentioned above. After calling Honeywell, the person agreed that the first choice seemed the most appropriate. If you have aux / emergency heat strips then it is a 2-stage heat system (NOT a multistage heat pump, which is a different animal). Of course you COULD have both a multistage heat pump AND aux / emergency heat, but that is uncommon. 4. I have heard twice now that heat pump/propane heat systems work just fine if you leave the temperature constant throughout the day/week, but have trouble with "recovery" when you let it dip in the evening and try to reheat in the morning when everyone rises. This seems to be the problem with these systems and programmable thermostats. Today I programmed every day and every "event" to the same temp to see if this pans out over the next few days. Ignore what you are hearing. ANY setback saves energy. Google for more information on this widely misunderstood topic. I AM going to get the HVAC contractor out here again, at my expense, to pick his brain in person, since I wasn't at home when he did the initial inspection for us. However, any insight to the above beforehand would be of great help. Thanks in advance. Good idea. |
#4
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I take it back. On setting 7, the heat pump comes on but nothing will
trigger the propane. Interestingly, I replaced the OLD thermostat, and the propane comes on, but NOT the heat pump. What the hell... John "Travis Jordan" wrote in message ... "JohnW" wrote in message ... The upper floor has a heat pump, presumably in the attic. When we had the home inspected I followed the guy into the attic where he pointed out the unit. My assumption is that this unit handles the heating/cooling of the 2nd story. It has a thermostat in the master bedroom and appears to work fine when the outside temp is above 20 degrees or so. I'm not worried about this system. A heat pump is just a reverse-cycle air conditioner. In your case it the air handler is in the attic - but the compressor for the AC / heat pump is outside. There are two units outside, one of which appears to be a dedicated air conditioner and a second unit that's a heat pump. Nope, they are both condensers, used in conjunction with your inside air handlers. Likely one or both are also capable of reverse cycle (a heat pump). We also have propane furnace/air handler. These units were controlled by a mercury-based manual thermostat, but I replaced it with a Honeywell RTH7400D programmable thermostat using the same wires (4 wires: g,w,y,r). For what it's worth, the propane also provides the heated water and a gas fireplace. G - Fan W - Heat (1st stage) Y - Cool (1st stage) R - Power Here are the questions: 1. Is the heat pump the primary heat source and the propane secondary, or the opposite? The inspection report calls the propane the primary source, but that doesn't seem right, and the seasonal contractor we had inspect the unit recently said the propane "appeared" to be the secondary. If it's not all that cold outside, the heat pump is on, but not the propane, for example. Today, at 16 degrees, both units run. And struggles to maintain 70. Most commonly the heat pump is primary (1st stage) and the propane would be secondary (2nd stage). Are you sure the old thermostat didn't have another wire for second stage heat? It could be that the furnance controller handles calling for the 2nd stage, but that is unusual. 2. The thermostat required a setup before programming the 7 days of the week. One of the steps was choosing the heating/cooling system. There are 10 choices: - heating and cooling (conventional) - single stage heat pump with no backup or auxilliary heat - heat only with no fan (conventional) - heat only with fan (conventional) - hot water heat only (conventional) - Cool only (conventional) - multistage heat pumps - multistage conventional heating and cooling (2 stages heat and 2 stages cool: requires w/w2 and y/y2 wires) - multistage conventional heating and cooling (2 stages of heat and 1 stage cool) - multistage conventional heating and cooling (1 stage heat and 2 stages of cool) Right now I have it on the first setting. Makes sense with only four wires. Are you SURE there wasn't a fifth wire? 3. What are the "stages" regarding heating systems as referred to above? My assumption is that a heat pump with emergency/auxilliary heat is a multistage heat pump (like the one in our attic for the second floor) but does it also refer to a secondary heating source like natural gas, oil or propane? If I had a W2 wire I suspect the 9th choice would be the most appropriate but I just had the 4 wires mentioned above. After calling Honeywell, the person agreed that the first choice seemed the most appropriate. If you have aux / emergency heat strips then it is a 2-stage heat system (NOT a multistage heat pump, which is a different animal). Of course you COULD have both a multistage heat pump AND aux / emergency heat, but that is uncommon. 4. I have heard twice now that heat pump/propane heat systems work just fine if you leave the temperature constant throughout the day/week, but have trouble with "recovery" when you let it dip in the evening and try to reheat in the morning when everyone rises. This seems to be the problem with these systems and programmable thermostats. Today I programmed every day and every "event" to the same temp to see if this pans out over the next few days. Ignore what you are hearing. ANY setback saves energy. Google for more information on this widely misunderstood topic. I AM going to get the HVAC contractor out here again, at my expense, to pick his brain in person, since I wasn't at home when he did the initial inspection for us. However, any insight to the above beforehand would be of great help. Thanks in advance. Good idea. |
#5
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"JohnW" wrote in message
... I take it back. On setting 7, the heat pump comes on but nothing will trigger the propane. Interestingly, I replaced the OLD thermostat, and the propane comes on, but NOT the heat pump. What the hell... What is the current outdoor temperature, and what was it when the HP was running? Most likely you have an outdoor temperature sensor that 'locks out' the HP when the OD temperature is below (fill in the blank) degrees.. |
#6
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"JohnW" wrote in message
... As an experiment, I put the face plate back on and pulled up the thermostat's setup menu where the heating/cooling system is to be selected and again browsed through the choices (note I've added details for the 7th item in parenthesis as written in the manual): 1 heating and cooling (conventional) 2 single stage heat pump with no backup or auxilliary heat 3 heat only with no fan (conventional) 4 heat only with fan (conventional) 5 hot water heat only (conventional) 6 Cool only (conventional) 7 multistage heat pumps (heat pump with auxilliary or backup heat) 8 multistage conventional heating and cooling (2 stages heat and 2 stages cool: requires w/w2 and y/y2 wires) 9 multistage conventional heating and cooling (2 stages of heat and 1 stage cool) 10 multistage conventional heating and cooling (1 stage heat and 2 stages of cool) I changed the setting from 1 to 7 and the other heat pump can on immediately! It cycles off and on periodically as it maintains 70 degrees. However, now the propane shut off, which always seemed to be running before. What is the make / model of the furnace to which you have the RTH7400 connected? Also, do you have the wires connected to the "conventional" or "heat pump" terminals on the new thermostat? |
#7
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Travis Jordan wrote:
"JohnW" wrote in message ... I take it back. On setting 7, the heat pump comes on but nothing will trigger the propane. Interestingly, I replaced the OLD thermostat, and the propane comes on, but NOT the heat pump. What the hell... What is the current outdoor temperature, and what was it when the HP was running? Most likely you have an outdoor temperature sensor that 'locks out' the HP when the OD temperature is below (fill in the blank) degrees.. It sounds like your dual fuel (HP plus propane) system is designed to run on one or the other fuels depending on the outside temperature. That may not be the most efficient paridigm, but it is one that is especially popular in the northerneastern and midwestern parts of the U.S. Here in the south we run the HP all the time (well, down to 25 degrees or so which rarely happens), and supplement it with electric heat strips or gas if it is available. |
#8
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JohnW wrote:
The furnace appears to be made by International Comfort Products Corporation and is the NTG3/FBF model (at least the serial number have NTG3 as a prefix). The manuals says Installation 80+ Single Stage. Just as a matter of historical interest, Carrier (United Technologies) bought ICP in 1999. The programmable thermostat has only one set of terminals, but the inside of the terminals are coded for conventional lettering, and the outside are coded for heat pumps, but share the same hole for the wi Heat Pump Conventional C C G G* Y Y* O/B W* RC RC R R* The asterisks indicate which wires I've connected. Also, the RC and R are jumpered per instructions. A second post has: Conv. Heat Pump W2 Aux Y2 E L but nothing is connected there. W2/Aux is where you'd connect the 2nd stage heat (if you had a wire for it). I'll just see how fast I can get service in here to explain exactly what we have, what to expect, and confirm the programmable is set up correctly. It sounds like you are set up OK and that the outdoor thermostat is determining whether the HP or propane funance is used when the thermostat calls for heat. How is the system working today? |
#9
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I put the old thermostat back on, and it's working fine--the house is cozy.
Still no heat pump, but the propane seems to be doing it's thing now. Don't get it--the night/day temps are the same. Something's just not right with the programmable thermostat. I have a service tech coming out (again) on Wednesday, and I'll pick his brain. Thanks for all your input--it's been an education! John "Travis Jordan" wrote in message ... JohnW wrote: The furnace appears to be made by International Comfort Products Corporation and is the NTG3/FBF model (at least the serial number have NTG3 as a prefix). The manuals says Installation 80+ Single Stage. Just as a matter of historical interest, Carrier (United Technologies) bought ICP in 1999. The programmable thermostat has only one set of terminals, but the inside of the terminals are coded for conventional lettering, and the outside are coded for heat pumps, but share the same hole for the wi Heat Pump Conventional C C G G* Y Y* O/B W* RC RC R R* The asterisks indicate which wires I've connected. Also, the RC and R are jumpered per instructions. A second post has: Conv. Heat Pump W2 Aux Y2 E L but nothing is connected there. W2/Aux is where you'd connect the 2nd stage heat (if you had a wire for it). I'll just see how fast I can get service in here to explain exactly what we have, what to expect, and confirm the programmable is set up correctly. It sounds like you are set up OK and that the outdoor thermostat is determining whether the HP or propane funance is used when the thermostat calls for heat. How is the system working today? |
#10
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JohnW wrote:
I put the old thermostat back on, and it's working fine--the house is cozy. Still no heat pump, but the propane seems to be doing it's thing now. Don't get it--the night/day temps are the same. Something's just not right with the programmable thermostat. I have a service tech coming out (again) on Wednesday, and I'll pick his brain. Thanks for all your input--it's been an education! You are welcome. Unless you've miswired something (and I don't think you have) my supposition is that something is going on with the ODT (outdoor thermostat) control on your HP condenser. Let us know what the service tech finds? |
#11
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Travis:
After all this, here's what happened: The service tech arrived and I discussed all the issues. Several significant factors: 1. My assertion that one of the outside units was an air conditioner was correct! Our main floor/basement has propane heat and that's it! When I explained that his colleague got it all wrong, he told me I misunderstood. Yet the service ticket from two week's earlier had clearly written references to the "first" and "second" heat pump. Oh. 2. He spent a lot of time in the room with the furnace, fiddling here and there. Sometime later he indicated he could find nothing wrong. However, we have had several more days with sub-15 degree evenings, and the house is heating like a sauna. It's 12 degrees outside and the house is sitting at 72 with no problems. Something "changed". $108 dollars worth of labor, but at least we're warm. 3. I had wired the programmable thermostat correctly. I suppose having only 4 wires is pretty much idiot proof, although I'm sure you industry folks have seen it all. I wish I knew what was adjusted for you all, but frankly I'm just happy the system is working at this point. It's isn't getting all that much warmer soon! Thanks again. John "Travis Jordan" wrote in message ... JohnW wrote: I put the old thermostat back on, and it's working fine--the house is cozy. Still no heat pump, but the propane seems to be doing it's thing now. Don't get it--the night/day temps are the same. Something's just not right with the programmable thermostat. I have a service tech coming out (again) on Wednesday, and I'll pick his brain. Thanks for all your input--it's been an education! You are welcome. Unless you've miswired something (and I don't think you have) my supposition is that something is going on with the ODT (outdoor thermostat) control on your HP condenser. Let us know what the service tech finds? |
#12
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JohnW wrote:
I wish I knew what was adjusted for you all, but frankly I'm just happy the system is working at this point. It's isn't getting all that much warmer soon! Thanks for the follow up, John. Glad to hear that everything is working for you now. |
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