Honeywell Power Supply for F52E Single Cell 12½ x 20

The 208427 Compatible with the W8600

The 208427H power supply provides the connection for the W8600 remote indicator. The 208427H is for an F52E with the terminal strip as in photo below on right. The 208427 has a w8600e daughter card and includes the wiring harness and terminal strip for the W8600E.

If your F52E has an unused terminal strip because you are not using the W8600, you can use the 208425G power supply and internally not connect the unused terminal strip.

The 208427 series provides a connection for the W8600E whereas the 208425 series does not.

Photo shows power box with and without the terminal strip.

208427 not Air Flow Sensor Compatible

The 208427H does not require an air flow sensor. This power supply runs as soon as 120v is applied. Used in an F52E that is wired to the furnace blower or through a sail switch.

This power supply has been configured for use in a F52E without the air flow sensor. The animated photo below shows an F50E power box with and without the air flow sensor.

Honeywell has disabled the air flow sensor feature by cutting the jumper J8. Restoring the jumper will allow the use of an air flow sensor. The F52E was not manufactured with the air flow sensor. If your F52 has an air flow sensor, then it must be an F52F Series.

Setting Ionizer Current Jumper J6

The 208427H is preset for 1.05mA and used only for the single cell 12½x20 model. Unlike other 208427 versions, there is not a jumper on the 208427H power supply board that needs to be set based on the overall size of your collector cells.

SIZE	IONIZER	J6
12 x 20	1.05 mA	1
16 x 25	1.65 mA	2
20 x 20	1.65 mA	2
20 x 25	2.10 mA	3

Power Supply Inspection

First visually inspect the board. Most problems are visible such as a melted transformer winding or a burnt component such as the surge suppressors RV1 RV2.

Check the thin white ceramic resistor R3, the corner wire can break away. This can cause the collector plates to get power but not the ionizer wires.

Continuous cell sparking (for months) can burn out components or wiring. Resonant sparking causes elevated voltage swings that can break down the insulation on the high voltage wires. Check for scorching.

Often the fuse blows when the switching FET Q1 shorts, we believe from line spikes. Check the fuse continuity. A blown fuse typically reads 4.4M ohm because of circuitry in parallel.

The fuse is soldered in and not replaceable. If there is an internal short the fuse blows so to prevent any components from flaring up. Replacing a blown fuse will not fix the problem.

Honeywell does not release the circuit board schematics. Service tech's want to replace the complete board and be confident. Honeywell does not sell the discrete components. We do not do component level repair of the boards.

Replacing the complete board with a new one with a 2 year Honeywell warranty would be the most reliable repair.

Power Supply Bench Test

Here is our procedure to test the 208427H power supply. Warning high voltage shock can cause death.

The 208427H has the air flow sensor disabled, the jumper J8 has been cut. This power supply does not require the air flow sensor to operate. The photo below shows the power supply 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 P2 will be 4.2k vdc
Terminal P5 for the neon lamp outputs 100 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 P3 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. See Spark Test pdf.

Evolution of the F50 Power Supply

The F50A was introduced in 1972 and has evolved in to the current F300. The same collector cells that were used in the F50A are still used in the F300. Thus variations of the current F300 power supply are used as the replacements for the prior F50 models.

In 1972 the F50A had an analog power supply as shown bottom-left. Then in 1987 the F50E was released, The F50E was the same as the F50A but with a new electronic power supply that offered two new optional features. The F50E offers an optional remote indicator and an air flow switch.

In 1993 the F50F was introduced with an all new chassis. The F50F now has all the electronics, from a 120v cord to the contacts for the cells built-in to the power box. Now a simple power box swap was a sure fix.

In 1998 the F50F Series 2 was released with a new optional LCD remote indicator that replaced the prior LED indicator. Also the internal power box wiring was improved with molex plug connectors. The connectors simplified manufacturing and power box repairs.

In 2000 the F300 was introduced that was identical to the F50F but the paint color was changed to blue. The F300 now has post filters that will also slide in to the F50F.

Warranty on Replacement Parts