Condenser Fan Question

Greg426

3 questions:



About 2 weeks ago, my condensor fan in my heat pump was seized up.  It was a 1/5HP 825RPM.  I took it in and they gave me a univeral 1/6-1/3HP 825RPM.



The nameplate shows RPM: 825  SPEEDS: 2.   That confuses me a little bit.  (Q1) Isn't it single speed, multi horse power?



Anyway, I used the "lo" wiring instead of the "high" since I figured 1/6 is closet to 1/5.  (Q2) Was I correct or should I have used the higher setting?



It's worked fine for 2 weeks, now today the outside unit had about 1" of ice on the lines.  Not on the condensor coils, but all of the larger piping in the middle below the fan.  (Q3) Is this related to an inproper fan speed or something else?  The filter was kind of dirty so that might have contributed.

RJ_4

horsepower

It all goes back to the size of cond. fan blade, a larger diameter blade would require a larger horsepower motor,  the 2 speeds should indicate 2 different rpm's, say 825 and 1050,  a larger horsepower motor can take the place of a smaller motor as long as the wiring and etc is big enough,  check the rotation on the motor and motor amps,   remember air flow restriction (dirty cond. coil ) on a propeller blade will increase motor amps,  can you provide all motor data and a picture

Greg426

Condenser Fan

The original motor was a 1/5HP so that's what the blades are rated for.  So should I use the 1/3HP or 1/6HP setting?



Also, would having an improper speed make the lines in the outdoor unit freeze up?

Techman

Cond fan motor

Lets say the original motor ( go with me here) was rated at 10 amps but actually drew 7.5 a , and the new smaller motor was rated at 7.5a and under a load the new motor drew 7.5 a ,then no problem.



Is the ice coming from the indoor unit , going to the outdoor , the other way around ? Or is the ice ball just there?

Greg426

Condenser Fan

The original motor was rated at 1.3A but I have no way of measuring the actual draw since it no longer spins. 



The indoor coils were not iced.  Nor were the outdoor coils.  The ice was on all of the heat pump copper lines around the compressor below the fan and where the line goes into the house.

RJ_4

cond fan motor

I am assuming the unit is in cooling.   i would wire the motor for high speed, check that your motor amps dont exceed rated amps, check rotation.  freezing of suction line outside unit and at compressor would indicate other problems, possibly air side issues

Techman

Ok

If the ice is on the larger of the two lines, then that means ,in the cooling mode the indoor coil (evap) is probably frosted (1st) and worked its way out to the comp.



Measure the new motor running amps. Without allowing for bypass air.



And as per RJ

Greg426

Running Amps

With the "high" connection I get 1.4A.   With the "low" connection 0.8A.

Greg426

Compressor amps

Those currents are under normal conditions.   What do you mean about not allowing for bypass air?

Techman

Fan

On some units ,when removing the control panel cover ,to gain access to the cond fan motor wirers to test the amps, sometimes the removed cover also allows for air to," bypass "the cond coil ,raising the motor amp reading , and head press. Those amp readings you have now have to be compared to the motor nameplate

Greg426

Motor Amps

Nameplate shows 1.9 and 1.2.

unclejohn

Use HI

Speed. Turn your system "heat - off - cool " switch at teh Tstat to off. Run your indoor fan by setting that switch on your tstat to " ON ". Wait untill no more water runs out of you drain line or at least 3 hours if there is still any ice on the outdoor unit. If after that it ices up again you need to call someone in.