Red "Check" light on Carrier Thermostat

I set the thermostat to run the emergency heat strips on a Carrier heat pump. The emergency heat strips operated fine, but a red light labeled “Check” was on the whole time the heat strips were operated. Any idea what this light is telling me? I’ve never seen it before. Thanks in advance for the help.


. CHECK LED lights when something needs to be checked
or done to maintain efficient operation of system. See
heating system instructions for CHECK LED meaning.

It means when you write the report you state the “Red Check” light was on and recommend having a licensed and competent HVAC contractor check and service the system as is needed.

Lucky you - no heat liability. It got dumped elsewhere.

c [size=2]CHECK LED indicates compressor malfunction.

It is my understanding that this indicator light can be hooked up to any auxiliary sensor such as a dirty filters sensor etc…

In your case if the light only came on during the emergency heat operation, this may simply be the way the thermostat was wired indicating that emergency/auxiliary heat is on (similar to all other heat pump thermostats which label the light emergency or auxiliary heat). This prevents you from accidentally running just the auxiliary heaters without the heat pump for an extended period of time.

That could very well be, but how does a HI know that? I would call for an HVAC person to check it out.


refer to specialist, assuming only makes an A___ out me and you.

You dont! And, I can’t tell you anything from here either.

If everything works as it should by “operating things from the t-stat” as stated in the SOP, just tell your client that you “don’t know” and have their HVAC guy tell them when he comes to do his annual service.

I see no reason to spend $75 to find out what a light on the t-stat is for, but your clients may have more accumulated wealth than I. Advise them, and give them the option.

Well an indicator light usually means one needs to place a service call, I for certain would not ignore the check engine light on my car so what’s the difference.

You are a Home Inspector, not a car mechanic.

If you understand what that red light is about (or if you go out and get a code reader for your car), you can ignore some things you see and save your client (and maybe yourself) some money.

If you don’t understand it, report it and let someone educate you and your client. So the future, you may not likely be so eager to spend unnecessary time/money.

The point here is that this is not about the red light, but how the red light is labeled. I had all kinds of grief when they labeled the red light as emergency heat rather than auxiliary heat.

When I had an overload of “no heat service calls” on Heat Pumps (mainly due to adverse weather conditions), I would get the customer back up and running on auxiliary heat, over the phone, so their emergency call could be handled as a normal service call, only to arrive the following day with the house at 33 degrees and the stove and oven burners glowing red for heat. When asked why they shut off the heat, the reply was often that they were afraid to use the ***emergency setting ***on the thermostat!

To reiterate, the equipment was operating properly. The red light operated as a supplemental heat indicator. Considering observations #1 & #2, I would not have recommended further evaluation repairs. But that is me. I am not recommending you go outside your comfort zone or experience level.

The reason for posting stuff here is to learn, expand our comfort zone and increase our experience level.

We are not assuming here. We are operating outside our SOP. If you do not know HVAC and you do not want to learn by asking questions before spending your clients money I would recommend reverting to the SOP which puts this issue outside the scope of a Home Inspection.

The easy answer for HI’s is to refer it to others.
That does not make it the right answer.
That does not bring credibility to the industry.
It is often the cause of law suits because HVAC contractors will readily advise the client that “your home inspector should have…”!

David, you must be able to tell what is wrong with stuff with your mind or the best home inspector I ever talked to. We are not in the business of guesing what is wrong with the homes different systems to save the seller 75.00 bucks. What are you going to do when the buyer calls you up and says the unit is down and the service system light is still on? You appeareantly have more money than I do. If the light is on and you dont know why refer to someone else. There is reason why the manufacture installed a service this unit light.