Honeywell F50 User Manual

Air Flow Switch Operation
The air ow switch (AFS) senses differential pressure across its inputs. The AFS signals the air cleaner ON when a vacuum
is present at the unit. Removing the tubing and using a straw to apply a vacuum near the orice will turn the AFS ON.
Also blowing air into the unconnected input will activate the AFS.
This test will bypass the airow switch allowing the power supply to operate. If the indicator light does not turn on with
the airow switch bypassed, then this indicates a problem with the power supply. Note the collector cells should be
removed to insure the output is not being shorted.
Honeywell manufactured two AFS versions. The new version has a smaller circuit board. Zoom in to the photos to
determine your version.
Air Flow Switch Bypass Procedure
1. Bypass the AFS:
• (2012 - Present) Unplug the AFS then connect the two pins marked “bypass AFS” using a jumper wire.
• (Prior - 2012) Short the resistor to ground with a jumper wire, see photo for your model
2. The door interlock switch must be ON
3. Turn ON the On-Off switch
F300 F50 F52 Models ................................................................................................................. 2012 - Present
On the power supply, connect the two pins labeled “Bypass AFS” located on J3 with a jumper. To permanently bypass the
AFS cut the R16 jumper/resistor.
Tech Note ©
October 2013
Honeywell Air Flow Switch (AFS)
ElectronicAirCleaners.com
ElectronicAirCleaners.com
Bel-Aire ElectronicAirCleaners.com, Inc · 70 Case Avenue Seekonk MA 02771 · Ph: 774.901.4770
J3R16

Honeywell F50 Specifications

General

Brand	Honeywell
Model	F50
Category	Switch
Language	English

Summary

Honeywell Air Flow Switch (AFS) Operation and Bypass

Air Flow Switch Operation

Explains how the AFS senses differential pressure and signals the air cleaner ON when a vacuum is present.

Air Flow Switch Bypass Procedure

Details steps to bypass the AFS, including unplugging and connecting pins or shorting a resistor.

F300 F50 F52 Models Bypass

Instructions to bypass the AFS on F300, F50, F52 models by connecting pins labeled 'Bypass AFS' with a jumper.

Model Specific Bypass and Permanence

F300 F52F Models Bypass

Instructions for F300 F52F models, involving grounding a power supply resistor for bypass.

F300 F50F F50E F52 Models Bypass

Details bypassing the AFS for F300, F50F, F50E, F52 models, referencing permanent disabling.

Air Flow Switch Voltages and Dimensions

Air Flow Switch Voltages

Measured voltages for the AFS when the air cleaner is OFF and ON, showing wire color correlations.

4074ETH Dimensions

Provides physical dimensions and hole spacing for the 4074ETH model of the airflow switch.