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Heat pump is on......

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eugenepowers001

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Discussion starter · #1 ·
So I was driving on a long distance trip with the AC and heat off and everything else off for that matter. Suddenly I feel heat coming out. It is 60F outside and I wanted cold air in the cabin. So I turned the system on and it showed 68F. I lowered it to 60F and turned it off again. Now I was getting cold air from outside. So why would the heat pump be on if the system is off?
It happened before a few times.
 
#2 ·
If you are on a long trip, then I would assume that you are driving in HV mode. When the car is in HV mode, the heat pump does not operate once the engine warms up as the car then gets its heat from the engine coolant. My guess is that there may be a small amount of air that gets pushed through the ductwork, carrying some heat transfer from the engine running and heating up things. Turning the HVAC system on and lowering the temperature to 60 will cause outside air and/or air conditioning to cool the HVAC ductwork. This will result in cooler air from the ducts at least for a while.
 
Discussion starter · #3 ·
wscan said:
If you are on a long trip, then I would assume that you are driving in HV mode. When the car is in HV mode, the heat pump does not operate once the engine warms up as the car then gets its heat from the engine coolant. My guess is that there may be a small amount of air that gets pushed through the ductwork, carrying some heat transfer from the engine running and heating up things. Turning the HVAC system on and lowering the temperature to 60 will cause outside air and/or air conditioning to cool the HVAC ductwork. This will result in cooler air from the ducts at least for a while.
Click to expand...
1. I never turned the heat pump on. So why would heat pump be on in the first place? 68F was set there like always for months. I live in LA so I never use heating at all. I only use AC in the summer and not all the time. In fact last year I went to Bryce and it was 10F but I worn a warm jacket so I never turned the heat on.
2. Even if the ducts cooled off what prevents them from getting hot again?
Like I said, all of the controls were completely off. Another clue maybe that while I was driving in HV from the start I started with 10 miles EV left. By the time I ended it was 6 miles left. So somehow the system used about a KW of electricity. Actually more, because it got charged a little every time I drove downhill but then it got discharged again. So it went from 10 to 8 then back to 10 and eventually to 6. And since it was a daytime I turned the lights completely off.
 
#4 ·
1. As I said, in HV when the car is warmed up, the heat pump does not come on. It is heat generated by the engine plus the sun that warms up the HVAC ducts and allows a bit of warm air in.
2.The ducts will get warm again.

In HV mode, the number of EV miles left varies, especially in hilly areas. The electric motor is frequently supplementing the ICE power, thus using battery capacity. HV mode attempts to maintain the existing EV miles, but it will vary up and down depending on how much the electric motor supplements the ICE. It also allows the battery power to be used when there is not much power needed using only electric propulsion. The car will slowly replenish the battery once the ICE starts again. The drop to 6 EV miles is probably caused by either low power needs while driving (EV light on dash is on) or use of electric power to supplement the ICE.
 
Discussion starter · #5 ·
wscan said:
1. As I said, in HV when the car is warmed up, the heat pump does not come on. It is heat generated by the engine plus the sun that warms up the HVAC ducts and allows a bit of warm air in.
2.The ducts will get warm again.

In HV mode, the number of EV miles left varies, especially in hilly areas. The electric motor is frequently supplementing the ICE power, thus using battery capacity. HV mode attempts to maintain the existing EV miles, but it will vary up and down depending on how much the electric motor supplements the ICE. It also allows the battery power to be used when there is not much power needed using only electric propulsion. The car will slowly replenish the battery once the ICE starts again. The drop to 6 EV miles is probably caused by either low power needs while driving (EV light on dash is on) or use of electric power to supplement the ICE.
Click to expand...
1. But the ducts did not warm up again after I turned the temp to 60F.
2. And the HV icon was always on. It never switched to EV or EV/HV. And I never heard the engine turned off either even on the down slopes. Also, this happened on return trip. On the way there I started with 52 miles EV, drove 10 miles in EV, switched to HV and arrived with 42 miles EV left. This is 280 miles trip one way. At the destination I drove in EV until 10 miles left. Pump the gas and went back. So why I didn't arrive with 10 miles left?
 
#6 ·
2. The "HV mode" indication will always stay on in HV. If the ICE shuts off, a little green blob sort of in the shape of the car with EV on it comes on when the ICE is off. This indicator is also on most of the time in "EV mode" as well. You did not arrive with 10 miles left because the car did not have time to replenish the EV miles before you stopped. The charge rate normally is at a slow rate when replenishing.
 
Discussion starter · #9 ·
Sandroad said:
How do you know the heat pump is on? Is there an indicator?
Click to expand...
No indicators besides it got hot in the cabin and air from the outside would not get in. It was 60F outside. But as soon as I turned the system ON and then turned the temp down to 60F and turned the system off right away cold air started to come in instantly. This is not the first time it happened. One time temp outside was like 76F but the heat started for no reason at all with the panel completely off and it got extremely hot. I had to do the same thing. Turn it on, change the temperature and turn it off. It doesn't happen often but it happens. Obviously if I take it to the dealer they will not be able to duplicate it.
 
#10 ·
So is it possible it’s heat from the engine coolant that’s available in HV mode and not the heat pump? Your description of it happening suddenly makes me think so, because heat pumps gradually ramp up heating/cooling as the compressor starts to operate and send fluid through the system. If your vehicle is under warranty I’d take it to a dealer anyway because there is always the possibility of stored trouble codes if there is a problem. In the meantime, I wonder if a solution is to simply keep the HVAC turned on all the time and set to a comfortable temperature. Since that’s how it’s designed, it may be happier.
 
Discussion starter · #11 ·
Sandroad said:
So is it possible it’s heat from the engine coolant that’s available in HV mode and not the heat pump? Your description of it happening suddenly makes me think so, because heat pumps gradually ramp up heating/cooling as the compressor starts to operate and send fluid through the system. If your vehicle is under warranty I’d take it to a dealer anyway because there is always the possibility of stored trouble codes if there is a problem. In the meantime, I wonder if a solution is to simply keep the HVAC turned on all the time and set to a comfortable temperature. Since that’s how it’s designed, it may be happier.
Click to expand...
What prevented the same thing happening again after I lowered the temperature and shut the system off again? It does not happen all the time.
 
#12 ·
eugenepowers001 said:
What prevented the same thing happening again after I lowered the temperature and shut the system off again? It does not happen all the time.
Click to expand...
I suggest you run a test and keep the system on at a comfortable temperature for a month and see if the sudden heat problem occurs. If it does you’ll have another data point to take to the dealer.
 
Discussion starter · #15 ·
Sandroad said:
Leave the heating and air conditioning system on for a month. Do not turn it off. See if you get any unusual heat or cool events.
Click to expand...
I think that is a stupid idea. I don't want to freeze or get hot at all. Sorry but I don't see how it will prove anything. Besides, I drive in EV mode most of the time so the engine is not on unless I go on the long distance trip.
 
#16 ·
eugenepowers001 said:
I think that is a stupid idea. I don't want to freeze or get hot at all. Sorry but I don't see how it will prove anything. Besides, I drive in EV mode most of the time so the engine is not on unless I go on the long distance trip.
Click to expand...
Do you have the automatic climate control system or the manual? Yes, for the manual, you have to constantly make adjustments, including turning it on and off, to stay comfortable.

But I have found that with the automatic, I just put it in auto mode, set the desired temperature, and I am comfortable year round regardless of the weather or season.
 
#17 ·
wscan said:
If you are on a long trip, then I would assume that you are driving in HV mode. When the car is in HV mode, the heat pump does not operate once the engine warms up as the car then gets its heat from the engine coolant. My guess is that there may be a small amount of air that gets pushed through the ductwork, carrying some heat transfer from the engine running and heating up things. Turning the HVAC system on and lowering the temperature to 60 will cause outside air and/or air conditioning to cool the HVAC ductwork. This will result in cooler air from the ducts at least for a while.
Click to expand...
Changing the subject a bit for my own clarification. In the quote above, I've highlighted a statement of yours. It seems to me, that the heat pump is used for both heating and cooling. Furthermore, if the ICE is on, then instead of using the heat pump for heat, it instead uses heat from the ICE. However, the heat pump would still be used for cooling. Am I correct?

Assuming that I am correct, your statement is true for heating, but not cooling.

/Jim
 
Discussion starter · #18 ·
FKHeath said:
Do you have the automatic climate control system or the manual? Yes, for the manual, you have to constantly make adjustments, including turning it on and off, to stay comfortable.

But I have found that with the automatic, I just put it in auto mode, set the desired temperature, and I am comfortable year round regardless of the weather or season.
Click to expand...
I can't make any adjustment if the system is OFF. And if the system is OFF then AC or Heat pump should not be working. And in that case only outside air should be entering the cabin.
Another possibility is that if there is some kind of the trap door that redirects hot air from the engine in to the cabin was not in the correct position.
 
Discussion starter · #19 ·
FLYNZ4 said:
Changing the subject a bit for my own clarification. In the quote above, I've highlighted a statement of yours. It seems to me, that the heat pump is used for both heating and cooling. Furthermore, if the ICE is on, then instead of using the heat pump for heat, it instead uses heat from the ICE. However, the heat pump would still be used for cooling. Am I correct?

Assuming that I am correct, your statement is true for heating, but not cooling.

/Jim
Click to expand...
I did not make that statement.
 
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eugenepowers001
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