What does br mean?

The "4" only indicates which program is currently running. This thermostat does not display furnace error codes.

In a heating system that uses hot wire ignition for natural gas or propane, this behavior may indicate the furnace failed to detect a flame when the cycle starts. You may get warm air briefly, but because the flame detector isn't working, the system shuts down. After a while, it purges any gas and tries again. The controller board in the furnace may have an indicator light that flashes an error code - look for a label on the access panel that describes what it means.

One common cause of this problem is a buildup of contaminants on the flame sense rod (often the same rod that heats red-hot to ignite the gas). Turn off the power to the furnace, wait for it to cool, then inspect the rod. If it has a whitish film on it, clean that off with Scotch-Brite (TM) or similar product (don't use sandpaper). The flame sensor works by measuring a tiny electrical current through the flame. A buildup of combustion products on the sensor blocks this current.

Warning: if you are not absolutely certain about which part is what in the furnace, don;t take any chances, call in a professional. This is a critical gas safety component.

http://www.ehomeservices.com.sg/articles/how-to-solve-air-conditioner-light-blinking-problem.html

If you see the red flashing light during regular operation, this usually means that the outdoor unit was shut off due to a problem and is currently "locked out" from normal operation. When you see the red flashing light, it is usually in a diagnostic feature to alert the HVAC repair technician to what the problem is.
https://www.onehourheatandair.com/bay-area/about-us/blog/2016/may/what-does-a-thermostat-red-blinking-light-mean-/

Either the unit is over heating and being thermally shut down or the temp shutdown switch is shutting down prematurely.

The unit was running when we came in. No Storms in the area. it was blowing hot air, but was still on the cool setting. There was a burnt wire smell coming from the unit. And the diag. code was Br. I found this odd since it still had power.

Usually Indoor Unit Anti-freezing protection (Cooling
Mode) or Over-heating Protection (Heating Mode)
for Evaporator
A) Indoor room
temperature too low
under cooling mode,
Too high under
heating mode
B) Indoor unit filter or
evaporator too dirty
C) Indoor unit fan motor
blocked
D) Insufficient refrigerant
under cooling mode
E) Indoor unit evaporator
sensor wrong
connection or failure

Ruud UBHC-SERIES is a HEAT PUMP AIR HANDLER
AND FAN COIL UNIT

Compressor and condenser not included

Spec sheet go here
http://yaunco.com/pdfs/rheem/ubhc_specs.pdf

According to the Owner's Manual if the Error Code flashes "06" the O.D. coil Temperature > 175 Deg
F for 2 consecutive minutes. (Heat Pump models only).

The action taken by the unit is Alternate flash set point and error code. Shut unit down for 5 minutes, then try again 2 times, if fails the 3rd time, then shut down unit.:

All of this is can caused by several things:

• Dirty filters
• Dirty coil
• Fan motor failure
• Restricted air flow
• Improper refrigerant charge
• Restriction in refrigerant circuit

The dirty filters, dirty coil and restricted air flow you can troubleshoot and solve yourself. The reaming ones should be handled by a an authorized service technician.

Here's a link to your Owners Manual, that you can download and print for future reference.

http://www.ajmadison.com/ajmadison/itemdocs/92008705_9-07_PTAC_IO_manual.pdf


Hope this helped to to troubleshoot and solve the problem . Please let me know. Thanks.

I was wondering the same thing about our unit until I found the specs online and read that it has freeze protection. When the temp goes below 40 degrees, the fan comes on to prevent damage to the unit.

Looks like 4 flashes might be high limit fault on this furnace. (I don't have a manual for this furnace, just searched online for the code meaning) Is the unit running flame at all? Is the unit running flame for a while then shutting flame off before desired temp is reached? Does the main air fan turn on to circulate air through your diffusers? Does it feel like the unit has much air flow out of the diffusers if the fan is running? Is your air filter clean? If it is infact your high limit switch, it is usually caused by not having enough airflow through the furnace and overheating occurs.

Hope this helped, let me know if I can assist you further :)

The blower motor kicks on when there has been a 24 volt control failure.

This usually means that a limit switch has tripped.

Most likely that would be a high temp limit switch or a rollout switch.

First, make sure the filters are clean. and the evap coil is clean. If eaither are dirty/clogged, it will partially block airflow, causing the furnace to overheat, causing the high temp limit to trip.

A rollout switch typically trips for three reasons.
1 flame rollout into the burner compartment due to poor airflow.
2 overheating af teh metal plate the rollout is mounted to, due to dirty, old, rusted components.
3 a bad limit switch.

If your unit has an LED light, count the flashes and it will hepl popint out the problem.
(locate the wiring diagram/flash code list, and correspond the flash count, with the code.)

First, check filters.