BENDIX BW1450 manual Thermostat Disassembly Refer to Figures

3/8" bolts require replacement, insure that the replacement bolts are grade 5 minimum and the same length as the original bolts. Use of inferior bolts can compromise the integrity of the air dryer and lead to premature failure. Where a lower, right angle mounting bracket (instead of a lower mounting strap) is used; line up the marks made on the outer housing and end cover. Install the six (standard) 3/8" cap screws, lock nuts and twelve special washers. The two longer 3/8" cap screws will be used to secure the AD-4™air dryer to the right angle mounting bracket.

Note: If during the Operation & Leakage Tests it was determined that the thermostat was inoperative, use the following procedure for repair or replacement. It is not necessary to replace this unit each time the end cover is rebuilt. Use thermostat maintenance kit 102657 for single terminal application. For dual terminal application, use kit #103982. (See Figure 5.)

THERMOSTAT DISASSEMBLY (Refer to Figures 5

and 8)

1.Remove nut (2), then lockwasher (3), plain washer (4), nut (2) and o-rings (5). Discard o-ring and retain other parts.

2.Remove and retain four Phillips head screws (7) and cover (6).

3.Remove and discard gasket (10).

4.Remove and retain spacer (11).

	DELIVERY		HEATER
	PORT	2	VOLTS/WATTS
SAFETY	6		EMBOSSED
VALVE			HERE
			CONTROL
			PORT
4
			5

SUPPLY

PORT

1&9

	3
7	8

MOUNTINGHOOK

BRACKET

FIGURE 8 - AD-4™AIR DRYER END COVER WITH TORQUE

PATTERN

5.Cut uninsulated thermostat wire at Point B, remove and discard thermostat and terminal assembly (1).

6.Clean remaining wire attached to heater terminal.

7.Clean thermostat “pocket” in end cover (9).

THERMOSTAT ASSEMBLY (Refer to Figure 5)

1.Cut uninsulated lead of new thermostat (1) at Point A.

2.Install thermostat in end cover pocket and position uninsulated leads next to each other.

3.Using a soldering heat sink, clamp uninsulated leads at Point B and solder leads with straight rosin core solder. Do not use acid core solder as corrosion can result. Clean excess solder off end cover.

4.Install thermostat terminal (1) in cover (6).

5.Install o-ring (5), washer (4), and nut (2). Torque nut to 20-30 inch pounds. Then install lockwasher (3) and nut

(2) finger tight to allow for reconnection of electrical wire when reinstalled on vehicle.

6.Install spacer (11) over thermostat (1).

7.Install gasket (7) and thermostat cover (6) and secure thermostat cover to end cover (9) using screws (7) and lockwashers (8).

8.Torque to 20-30 inch pounds.

9.Test thermostat as follows:

A. At a temperature above 90 degrees Fahrenheit, check resistance between thermostat terminal (1) and end cover (9). Resistance should be 1,000 ohms or greater; if not, check for solder “path” short.

B. Chill entire end cover assembly to 40 degrees Fahrenheit or below and check resistance again. Resistance should be 2-4 ohms for a 12 volt, 60 watt end cover and 4-7 ohms for a 24 volt, 120 watt end cover.

	UNLOADER
	“UNL”	GOVERNOR
	PORT
		RESERVOIR
COMPRESSOR		“RES”
	AD-4™	PORT
SUP	AIR
	DRYER
	CON
8-10 AMP FUSE	DEL	SUPPLY
TO IGNITION		RESERVOIR

FIGURE 9 - AD-4™AIR DRYER INSTALLATION SCHEMATIC

10