Honeywell Power Box Assembly for F50A F50E with AFS 240V Replaces 208420B

Setting Ionizer Current Jumper P5

The powerbox needs to be configured for five sizes: 12½x20, 16x20, 16x25, 20x20, 20x25. A jumper on the power supply board needs to be set based on the overall of you air cleaner. This jumper (P5) sets the ionizer current. The J8 jumper drops the voltage from 8150v to 7500v for less ozone output.

Bypass Air Flow Sensor Feature

To enable the power box to power up without the use of the air flow sensor permform the following step.

Connect the two pins together labeled 'bypass AFS" on J3 using a jumper; or to permanently bypass the AFS, cut the R16 resistor.

• AFS Bypass Instructions

The PS2402B12J is Compatible with the W8600

The PS2402B12J power box provides the terminal strip for the optional W8600E remote indicator. The 120v PS2402B12J replaces any F50A or F50E power box with or without the terminal strip as shown in photo below.

If your power box does not have a terminal strip or has an unused terminal strip, then you can use the PS2402B12J and simply leave the terminal strip unconnected. Otherwise a W8600E would connect with a 4 conductor thermostat wire whereas a W8600F would use a 3 conductor wire.

The PS2402B12J can also be used with the newer W8600F by replacing the internal daughter card, wiring harness and terminal strip with that included with the W8600F. Read More...

Photo shows power box with and without the terminal strip.

PS2401B12J is Air Flow Sensor Compatible

The PS2401B12J has a built-in air flow sensor. The air flow sensor detects air flow by sensing a vacuum (differential pressure drop). This power box will wait until air flow is sensed and then turn on. This power box can be used in an F50A-E that is wired to a full-time 120 volts or used when 120v power is only supplied when the furnace blower is running.

Some earlier F50A, F50E power boxes did not have the air flow sensor. The PS2401B12J replaces power boxes with or without the air flow sensor. If your prior power box does not have the air flow sensor, then the PS2401B12J built-in sensor will simply be redundant. The photos below shows a power box with and without the air flow sensor.

• Powerbox w/ & w/o AFS

PS2401B12J Air Flow Sensor Nozzle Retrofit

The PS2401B12J replaces power boxes with and without the air flow sensor. In 2004 Honeywell discontinued the power box without the AFS (208421C) to consolidate inventory.

The air flow sensor feature was introduced 1991. The F50A and F50E prior to 1991 did not have the AFS and do not have the hole for the nozzle. The AFS senses the vacuum of the return duct and signals the power supply to turn on.

If replacing a power box without the AFS, then check that your frame has the hole for the nozzle. Without the hole the PS2401B12J will not sense the vacuum and turn on. See the Tech-Note.

• F50A AFS Nozzle Tech Note

Power Supply Bench Test

The following is our procedure to test the power supply. Warning high voltage shock can cause death.

The power supply has the option to disable the air flow sensor (see bypass AFS section). The AFS can be temporary disabled for testing by borrowing jumper from J8 to connection J3 position marked "bypass AFS". This power supply does not require the air flow sensor to operate. The photo below shows an older power supply that just needs 120v to power a cell.

Connect 120 vac to terminals P1 and P2. Check the following outputs with respect to chassis ground.

Terminal P3 will output 8.2k vdc
Terminal P4 will be 4.2k vdc

Since high voltage meters are not common, Honeywell provides the neon lamp as reliable voltage indicator. If the high voltage output falls below spec the neon lamp voltage will drop out.

Shorting P3 or P4 to ground has the same effect as the test button. The short will temporarily cause the neon indicator to go out. By tapping P4 to ground you should be able to draw an arc 1/32". Tapping P3 to ground can produce a larger arc near 3/16". These tests are with out the cells connected, the arc will be twice the length with cells connected.

• Spark Test Tech Note
• Power Supply Instructions

Warranty on Replacement Parts

The Honeywell warranty for F50 Replacement Parts is 2 years from the date of purchase. Our customers simply need to ship us the defective part. We test and confirm defective. We then ship back a brand new part at no charge.

• Power Supply Warranty