Does outside unit run when thermostat calls for auxiliary heat ?

SOURCE: ruud heat pump outside fan

You may be right in looking at the motor. It uses a different speed on heat than cool. The heat cycle uses low speed, usually red. Some manufactures use blue (medium). Cool uses black, high speed. If you are confident, switch the low speed wire with the high speed and see if this changes anything. If the fan motor isn't the problem, check the other setting (cool) if the overload trips, you may need to look into a new capacitor or compressor, if so, you can install a hard start kit. these are start boosters, and are inexpensice, sometimes they will give another year out of the comp. but I've put them on and they have lasted 5 years.

SOURCE: intertherm outside unit - s3ba-036k - does not run

Measure the voltage across the line. The outside unit normally runs on 220 Volts. Measuring each side of the line to ground will give 110 Volts. If your outside disconnect is of a fused type one fuse could be blown. If a fuse is blown on one side of the line you will read zero volts differential across the line.

Check the type of fuse used in the disconnect. Make sure the proper size time delay fuse is installed on both sides of the line at the disconnect.

Allen Neal

• 359 Answers
• Posted on Nov 08, 2008

SOURCE: Blower in Attic not running

inside unit has fan control relay , either on control board or can be separate ,except for the 24 volt transformer and the t-stat the units operate separately concentrate totally on the inside unit this is where the problem lies

SOURCE: heat pump auxiliary heat does not turn on

Turn up your outside thermostat in the outside unit.
You should have about 3 degrees difference in one stage to the next. So I would change the thermosat with one that has three stages of heat.

SOURCE: thermostat wiring diagram for heat and cool unit

use an ON-OFF controller whose output can be given to themostat or a circuit breaker....