For my own sanity!

[Bikerjake]

Hello gentlemen,
Currently my family is selling a house and a home inspection was done. According to the inspector the heat pump during auxiliary heat was fine but the emergency heat was not up to snuff.

AHU-
Trane #4TEE3F31A1000AC

Outdoor unit
Trane #4TWX4030B1000A

Thermostat
Honeywell FocusPRO TH5220D

Electric Heaters
BAYHTR1410BRKBA 9.6kW

Anyways I head over to the house to check things out. Pulled AHU cover and measured 19 amps going to both elements. This is a variable speed AHU. I can provide dip switch settings if it will help.

My question is why does this inspector think that the emergency heat is supposed to be equal to the auxiliary? To me this system seems to be operating just fine. Am I wrong to think that on this system emergency temperature will be less than the auxiliary temperature?

[motoguy128]

"emergency" heat is he same as auxillary. ITs' just the terminology iin terms of how you operate teh thermostat. When the thermostat is set to "EM heat" ONLY the eletric heat strips will run, hte compressor is shut off. Under normal operation the compressor runs anytime there is a call for heat, and aux only comes on as a 2nd stage when more heat is needed, or during defrost.

If the heat strips work in normal heat mode (you can test buy raising the tmep at least 3F, it should force auxillary heat to come on), but do not in EM mode. Then it might not be wired correctly. Sometimes I think a seperate "E" terminal is used. But I honestly never understood why.

[motoguy128]

FYI, most imspectors only have a ver,y very basic understanding of HVAC. They are jack-of-all trades, master of none types. They (hopefully) know a little about everything, but few know more than that.

My only guess is that he thinks the heat pacakge isn't large enough for the size of the home. I have now idea how he'd know that unless it was almost at design temepratures (really really cold).

Otherwise, maybe he measured the temperature at the registers and thinks it's too cool. It might jsut be that the airflow, being vairable speed, is higher than he's used to. He might be used to oversized units on restrictive ductwork that are short on airflow, so a 60F or more temp rise is normal to him. With that size heater, you should see a 30F temp rise if airflwo si set to the normal 400CFM/ton on the dip switches, or 1000CFM total.

One final thought, maybe the aux heat has 2 stages, and only 1st stage came on when he tested it, so the temp rise was lower.

When in heat mode with the auxillary, at about 50F outdoor temp, the total capacity would be around 60k BTU's so you'd see a 60F temp rise total. When the compressor is running by itself, it would be abotu a 30F rise at that same temeprature. At about 35F it's would be maybe a 25F rise.

[Bikerjake]

I only saw one contactor inside the Ahu which led me to believe that those were the only heat strips. The dips are set for the 400 cfm. I generally deal with water loop systems and generally don't get to deal with heat pumps.

[mark beiser]

If there is no jumper between the Aux and E terminals in the thermostat, the heating elements won't come on in the emergency heat mode unless the set temperature is a couple of degrees higher than the room temperature.
If the terminals are not jumpered, and the inspector only bumped the temperature up 1 degree above the room temperature, it may have been just the fan running.

[catmanacman]

was it 19 amps per element or 19 amps at the main line

[Bikerjake]

19 amps per element

[BaldLoonie]

Mark is probably right with what's going on. Seen it frequently.

[Bikerjake]

I am curious about that jumper wire. If by chance that is the case. Would there be any literature that I could show to the future home buyers for proof? Honeywells website perhaps?

[RyanHughes]

I am curious about that jumper wire. If by chance that is the case. Would there be any literature that I could show to the future home buyers for proof? Honeywells website perhaps?

Yes.

[catmanacman]

if you turned on the emergency heat and you strips are drawing 38 amps your good .on the trane varible speed dip switch 7- 8 control the air flow while the strips are on

[energy_rater_La]

Home Inspector's job is to alert homeowner, prospective buyer or who ever pays
for the inspection of items with questionable performance.
Knowing a little about a lot of things is his/her expertiese of their trade...
home inspectors.

They are not builders, electricians, insulatiors, or hvac tradespeople.
Unless they advertise as such.

One thing any inspector learns quickly, is to not do invasive testing.
The old last one touched it, is the one who broke it mentality is
the basis for lawsuits, and bad feelings between home owners
inspcectors & tradespeople.

Seems the HI has done the job hired for, now OP is checking into
operation of emergency heat.

[wahoo]

Opinions are like rectums, no one wants to hear them and most of them stink. Most home inspectors are hired by the perspective buyer with a "double" purpose. To find SOMETHING wrong to justify their expense, and protect the buyer from horrible, unseen problems. I'd take this opinion with a grain of salt, and not be "pushed" into anything.