Richard Thacker
03-08-2009, 06:52 AM
Gentlemen I have a question that I would like explained, if possible, by someone with some knowledge of motors.This occurred last year...
Example: 3.5 ton system / with a listed R.L.A. of 18.4 Amps / Outdoor temp is 91*F / Return air is 74*F / Supply air 58*F / Actual observed R.L.A 18.1amps / unit is 2 years old
I called for the system to be further evaluated by an HVAC Specialist because the RLA seemed to running to high and may be a sign of motor concern. The answer I recieved from the contractor who installed the unit was " The system is running normal and there is not a problem with amp draw. The higher amp draw is due to very high outdoor temperatures making the unit have to work harder."
Now I don't know a lot about motors, but I can not see how a system that under normal conditions would be running +/- 11.5 amps would need that much more power for a day that was only 91*F. What I would like to know, and explain it in simple terms:
1. Is the HVAC contractor correct?
2. If he is correct when did 91*F become "very high outdoor temperatures" and why would it cause such a high jump in the RLA?
Example: 3.5 ton system / with a listed R.L.A. of 18.4 Amps / Outdoor temp is 91*F / Return air is 74*F / Supply air 58*F / Actual observed R.L.A 18.1amps / unit is 2 years old
I called for the system to be further evaluated by an HVAC Specialist because the RLA seemed to running to high and may be a sign of motor concern. The answer I recieved from the contractor who installed the unit was " The system is running normal and there is not a problem with amp draw. The higher amp draw is due to very high outdoor temperatures making the unit have to work harder."
Now I don't know a lot about motors, but I can not see how a system that under normal conditions would be running +/- 11.5 amps would need that much more power for a day that was only 91*F. What I would like to know, and explain it in simple terms:
1. Is the HVAC contractor correct?
2. If he is correct when did 91*F become "very high outdoor temperatures" and why would it cause such a high jump in the RLA?