Overview
Compressor run capacitor, 25 µF, 440 V, oil filled. Phoenix part number 4035949-02.
A run capacitor is the part that gets a single-phase compressor turning and keeps it running efficiently. When it loses capacitance the compressor draws hard, struggles to start, and eventually will not start at all.
What it fits
- Phoenix R150 — named as item 7 in the 50 Hz service parts list, Capacitor, Compressor, one fitted
- Phoenix DryMax — named in the service parts list as Capacitor 25MFD
Specifications
- Capacitance: 25 µF (MFD)
- Voltage: 440 V
- Construction: oil filled
Do not substitute on voltage. A 370 V capacitor in a 440 V position will work briefly and fail early, and it will fail in a way that takes the compressor with it.
Check this before you condemn a compressor
This is the single most valuable thing on this page. A dehumidifier whose compressor hums, trips the thermal overload, or will not start at all is far more often a failed run capacitor than a failed compressor — and the capacitor costs a fraction of what the compressor does.
Symptoms worth checking a capacitor for:
- Compressor hums but will not start
- Compressor starts and cuts out on overload after a short time
- Machine runs but pulls down poorly
- Compressor starts reluctantly on a long extension lead but fine on a short one
A bulged, split or weeping capacitor is finished on sight. One that looks perfect can still be well below its marked capacitance — test it, do not judge it by appearance.
Safety
Capacitors hold a charge after the machine is unplugged. Discharge it safely before handling. This is not optional and the stored energy in a 25 µF capacitor is enough to hurt.
Note the terminal connections before you disconnect anything, and photograph them.
Related parts
Phoenix also list impeller capacitors of different values on the same machines — 4035235-09 on the R150 and 4037221-03 on the DryMax. Do not mix up the compressor capacitor and the impeller capacitor. Read the value on the one you are replacing.
Frequently asked questions
Can I fit a 370 V capacitor instead?
No. Match the voltage rating.
Can I fit a slightly different µF value?
No. Match the capacitance.
How do I test one?
With a multimeter that has a capacitance range, after discharging it. Well below the marked value means replace.
Which machines take it?
The R150 and the DryMax, from the Phoenix parts lists.
Compressor not starting? Tell us the machine and the symptom — a capacitor is cheap to rule out and it is the answer more often than not.
