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No emergency switch on heat pump


Robert E Lee
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Got to my second inspection today only to find the electrical power was shut off to the home. Completed as much of the inspection as possible, but in the process noticed that the heat source was a 1976 Lennox heat pump, further checking showed a standard thermostat i.e. "Cool" "Off" "Heat", but no selection for emergency heat...other heat pumps that I have checked (of which there are very few here in the north country), have all been equipped with an "Emergency" selection for the electric coils (it does have 3 coils). The power is to be turned on tomorrow, so will be returning later this week to finish the inspection, any help on how I can test the "Emergency" mode?

Robert E Lee

GENERAL Home Inspections, Inc

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Rob't,

I would guess it to be an electric furnace with a/c.

1. If it were a heat pump, there would most likely be a reversing valve visible in the outdoor unit.

2. Standard t-stats for heat pumps have 2 mercury switches.

3. I don't think I have ever seen a heat pump that old.

4. I lost count of how many Realtors and even sellers that have listed electric furnaces as heat pumps.

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Originally posted by Robert E Lee

Got to my second inspection today only to find the electrical power was shut off to the home. Completed as much of the inspection as possible, but in the process noticed that the heat source was a 1976 Lennox heat pump, further checking showed a standard thermostat i.e. "Cool" "Off" "Heat", but no selection for emergency heat...other heat pumps that I have checked (of which there are very few here in the north country), have all been equipped with an "Emergency" selection for the electric coils (it does have 3 coils). The power is to be turned on tomorrow, so will be returning later this week to finish the inspection, any help on how I can test the "Emergency" mode?

Robert E Lee

GENERAL Home Inspections, Inc

Sounds like it set up to run the strips all the time, which kind of negates much of the advantage of using a heat pump.

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Power was back on today, so went back at the end of scheduled inspections and found that indeed it is a heat pump (reversing valve, and thermostats with 2 mercury switches). Turned the unit on for heat breifly, and found that as you mentioned Mark the compressor was running and the electric resistance coils were drawing current. It was also equipped with a switch to select either the main floor thermostat, or the lower level thermostat for control...new wrinkle on dual zone heating!!

Robert E Lee

GENERAL Home Inspections, Inc

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Originally posted by Chad Fabry

A heat pump in Minnesota would have maybe ten days total where it would be an advantage. The rest of the time would be in full emergency heat mode anyway.

There is never a need to put a heat pump unit's thermostat to the emergency heat setting unless the heat pump is malfunctioning. All electric heat pump units automatically switch to heat however many stages of coils necessary to heat to the set temp when the heat pump is no longer providing the heat more efficiently than the electric coils. The emergency heat setting turns ALL COILS of the system on all at once instead of adding however many coils it needs in succession until the requested temp is reached.

My heat pump system has 6 electric heat coils. If the heat pump is not efficient to heat, each coil will activate in succession, as needed, until the unit can produce the desired heat temp. It may only take one coil, it may take all six, but it is done automatically. If I turn the t-stat to emergency heat, all six coils are activated and will stay activated to reach the desired temp each and every time the t-stat temp falls below the desired temp set.

If the heat pump is working as it is intended, the emergency heat setting will NEVER have to be selected.

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You're right Dan, my poor choice of words. Their bad choice of heating plant. That was my point. Installed in the middle of the energy crisis and never updated. Propane, oil or natural gas would all be cheaper to heat with unless the guy owns an electric company.

Heat pumps don't work well in the cold, as I'm sure you know, and I'm betting during the heating season Minnesota has a zero point zero average night time temp.

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Originally posted by Chad Fabry

You're right Dan, my poor choice of words. Their bad choice of heating plant. That was my point. Installed in the middle of the energy crisis and never updated. Propane, oil or natural gas would all be cheaper to heat with unless the guy owns an electric company.

Heat pumps don't work well in the cold, as I'm sure you know, and I'm betting during the heating season Minnesota has a zero point zero average night time temp.

I guess it depends on the area it is used (probably not good in Minnesota) and what one determines as expensive.

My entire home is electric. I ran the hell out of my heat pump furnace this past Winter. Kept it between 75-78 the entire time. My highest utility bill for my furnace, hot water heater, cooking, lights...everything, was $135. Add another $40 for water and for around here, thats a darn cheap utility bill! Of course I have a 99% efficient Trane system too. Even still, I have a Ranch style home with approximately 3,300 finished living space (finished full basement)that is heated or cooled. I am pretty impressed with its performance.

We have our share of sub-zero weather in the Midwest, but granted it is periodic and does not last as long as say Minnesota or upstate New York. If I were in one of those areas up North, I would probably still have my heat pump system, but I would put in a helper system like a pellet or wood stove on a thermostat to help take up where the heat pump is lacking in the colder climate

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