How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Phil Your Own Question
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8445
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
Type Your HVAC Question Here...
Phil is online now
A new question is answered every 9 seconds

I installed a new thermostat and it blows room temp air when

Customer Question

Hi, I installed a new thermostat and it blows room temp air when set to cool
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.


If you can send me photos of the new thermostat wiring where it attaches to the new thermostat, and where it ends up attached inside the furnace (usually on a printed circuit card mounted inside the blower compartment).. I will take a look at if for you.

Use the paper clip icon at the top right on the tool bar,

I will be in for another hour or two tonight, then back in the morning.


Customer: replied 1 year ago.
One is the old one and one is the new one. The new one has the electrical tape on the wires. My HVAC unit is a Carrier FV4CNF002... which may or may not be a "heat pump"? The new thermostat says it doesn't work with a heat pump with auxilary heating system. But this isn't even about heating... its for the AC, which just blows out room temp air.
Expert:  Phil replied 1 year ago.

Thanks, that Carrier FV4CNF002 is for the fan coil unit, I need the model number of the unit sitting outside.

and I very badly need a photo of the air handler printed circuit card where the thermostat wires connect..that is 'the other half of the story' regarding thermostat controls circuitry.


Customer: replied 1 year ago.
I attached the labels on the HVAC unit.
Customer: replied 1 year ago.
PS.. it does not sit outside. I live in an apartment and the unit is inside a closet.
Expert:  Phil replied 1 year ago.

Hello again, there are two copper tubes attached to the unit in your closet, that run outside to where the heat pump part of your unit sits... or it could be on the roof. I need the model number of that unit.

So far it seems that you might not have the electronics skills needed to sort this out, and to remove the blower service panel on the inside unit so you can take a picture of the printed circuit card INSIDE THE UNIT ITSELF.

If that is the case, tell me which direction you are from the very center of the city and the name of the city and I can find a well rated local technician hopefully that take care of this for you.


Customer: replied 1 year ago.
I don't have access to the roof so I can't get you any info on that unit. I'll contact the landlord and see what he has to say. So you can't do anything until you get the model number of that unit on the roof? I'll reconnect the old thermo unit until tomorrow then.
Expert:  Phil replied 1 year ago.

Hello again, that is a good plan.

It is also a good idea to let the landlord hire all the work that needs doing, if anything goes wrong with the system after you worked on it, you can be blamed and charged for all subsequent repairs.

Thermostat replacement is easy about 30% of the time, the rest of the time there can be problems.

If you feel like rating my work so far I will appreciate it, its how I earn a living, and rating does not increase your charges.


Related HVAC Questions