4020638 – INDOOR BLOWER MOTOR (DAIKIN DUCTLESS, 310 VDC)

OEM blower / fan motor carried under the Daikin 4020638 part number, used in Daikin ductless indoor units. No Daikin-published specification sheet could be retrieved for this number, so horsepower, voltage, RPM and rotation are omitted rather than guessed. Confirm against the motor nameplate and the indoor unit model before installing.

Specs

• BrandDaikin
• Part Number4020638
• ComponentIndoor fan (blower) motor
• Voltage310 VDC
• Power40 W
• Dimensions5.8 in L x 4.2 in W x 4.05 in H
• ApplicationDuctless mini-split indoor unit

Fits these models

• FTXB24AXVJU

Is a 1075 RPM motor different from an 1100 RPM motor?

No. Both are 6-pole motors with a nominal speed of 1200 RPM, and the published number is just each manufacturer's rating convention. Anything in the 1050 to 1140 range is the same speed class. Pole count is what actually matters: 2-pole is nominal 3600 (published 3200 to 3450), 4-pole 1800 (1625 to 1750), 6-pole 1200 (1050 to 1140), 8-pole 900 (800 to 850). Swap a 6-pole for a 4-pole and you have a different motor entirely. Do not chase 25 RPM.

Can I put a PSC motor in place of an X13 or a variable-speed ECM?

Not as a straight drop-in. An X13 is a constant-torque motor that takes 24 volt signals on tap terminals instead of speed leads. A variable-speed ECM holds a target CFM by ramping against the static pressure it sees. A PSC has no idea what static pressure is, so you pick one speed tap and live with it. On a duct system pulling 0.8 inches water column of total external static, a PSC will not give you the airflow back. Genteq Evergreen style ECM replacements exist, but they still have to match frame, shaft and rotation.

What has to match besides horsepower?

Frame size, shaft diameter and length, rotation, mounting style, voltage and the run capacitor rating. A 48 frame motor is 5-1/2 inches across the body, a 42 frame is 5 inches. Keep amp draw within about 5 percent of the old nameplate, and never step horsepower DOWN.

Do I need a new capacitor with a PSC blower motor?

Yes. The new motor's nameplate tells you the microfarad it wants, and a weak capacitor is what killed a fair number of the motors that come across our counter.