Bryant 581B installation instructions Ð Varislide Economizer Troubleshooting, Ð35Ð

Table 21 Ð Varislide™ Economizer Troubleshooting

	PROBLEM	CAUSE				REMEDY
Damper does not		Indoor (evaporator) fan			1.	Check to ensure that 24 vac is present at terminal C1 on the IFC or that
open.		is off.				24 vac is present at the IFO terminal. Check whether 24 vac is present at
						PL6-1 (red wire) and/or PL6-3 (black wire). If 24 vac is not present, check
						wiring (see unit label diagram).
					2.	Check proper thermostat connection to G on the connection board.
		No power to economizer			1. Check that SW3 is properly making contact with the damper blade. Check
		motor.				that SW1 is in the NC (normally closed) position.
					2.	Check diode D18. If diode is not functioning properly, replace economizer
						control board.
					3.	Con®rm that the economizer control board is grounded properly at PL6-4
						(brown wire) and at brown terminal of the economizer control board (brown
						wire). The economizer motor must also be grounded properly at the negative
						motor terminal (brown wire).
					4.	Verify SW1 and SW3 are working and wired properly (see unit label
						diagram).
					5.	Check for 24 vac input at both PL6-1 (red wire) and PL6-3 (black wire). If
						24 vac not present, check unit wiring (see unit label diagram). If 24 vac is
						found in both places, check for 24 vac at the yellow terminal of the econo-
						mizer control board (yellow wire). If 24 vac power is not present, replace
						the economizer control board.
		Economizer motor failure.			If the indoor (evaporator) fan and economizer motor are energized, verify that
					there is a minimum of 18 vdc at the positive motor terminal. If the motor is not
					operating, replace the motor.
Economizer operation		OAT or EC set too high.			1.	Set at correct temperature (3 F below indoor space temperature).
limited to minimum					2.	Check OAT or EC by setting above outdoor temperature or humidity level.
position.						If the OAT or EC switches do not close, replace OAT or EC.
		Economizer control board			1.	Perform the following tests when OAT or EC is closed, Y1 is called for, and
		incorrectly wired or not				damper is at minimum position. Con®rm 24 vac on gray terminal of the
		functioning.				economizer control board (gray wire). If 24 vac is not present, check wiring
						(see unit label diagram).
					2.	Verify that SW1 and SW3 are wired correctly and working properly (see unit
						label diagram).
					3.	Check to ensure that 24 vac exists at PL6-2 (blue wire). If 24 vac is not
						present, check wiring (see unit wiring label diagram).
					4.	Check 24 vac output at PL6-10 (white wire). If 24 vac is not present, replace
						economizer control board.
		Incorrect SAT wiring or in-			1. After verifying that the OAT and EC settings and the economizer control
		operative SAT.				board wiring are correct, check to ensure that the 24 vac terminal of the SAT
						has 24 vac (white wire). If OAT, EC, and control board are functioning and
						wired properly and no 24 vac exists, check wiring (see unit label diagram).
					2.	If supply-air temperature is greater than 57 F, 24 vac should be found at ter-
						minal T2 on the SAT (pink wire). If 24 vac is not present, replace SAT.
Damper does not		Incorrect economizer			1.	Verify that SW2 and SW4 are wired and working properly (see unit label
close.		wiring.				diagram).
					2.	Check diode D19. If diode is not functioning properly, replace economizer
						control board.
		Incorrect damper actuator			1.	After verifying that the wiring is correct, modulate the damper to the mini-
		wiring or inoperative econo-				mum position. Remove the calls for G.
		mizer circuit board.			2.	If the damper does not move, check for 24 vac at PL6-1 (red wire). If 24 vac
						is not present, check wiring (see unit label diagram).
					3.	If damper still does not move, check for 24 vac at blue terminal of econo-
						mizer control board (blue wire). If 24 vac is not present, replace the econo-
						mizer control board.
		Incorrect SAT wiring or in-			1. After verifying that the wiring is correct and the economizer control board is
		operative SAT.				functioning properly, place the OAT or EC switch in the closed position.
						Place a call for Y1 and open the damper to the fully open position. Con®rm
						that the 24 vac terminal of the SAT has 24 vac (white wire). If 24 vac is not
						present, check wiring (see unit label diagram).
					2.	If supply-air temperature is less than 52 F, 24 vac should be found at termi-
						nal T1 on the SAT (violet wire). If 24 vac not found, replace SAT.
		Economizer motor failure.			If economizer control board and SAT are functioning properly, verify that there is
					a minimum of 18 vdc at the positive motor terminal. If a minimum of 18 vdc is
					present and the motor is still not operating, replace the motor.
Economizer damper		Insufficient battery power, in-			1.	Check voltage potential across batteries. If lower than 14 vdc, replace close-
does not close on		operative economizer control				on-power-loss power supply (9-v alkaline batteries). Check this emergency
power loss.		board.				power supply on a regular basis or whenever the ®lters are changed.
					2.	If the close-on-power-loss and economizer control board are functioning
						properly, check for 14 vdc or higher at the blue terminal of the economizer
						control board (blue wire) when power is disconnected from unit. If 14 vdc is
						not present, replace the control board.
		LEGEND
CI	Ð Common		OAT	Ð Outdoor-Air Thermostat
EC	Ð Enthalpy Control		PL	Ð Plug
IFC	Ð Indoor (Evaporator) Fan Contactor		SAT	Ð Supply-Air Thermostat
IFO Ð Indoor (Evaporator) Fan On			SW	Ð Economizer Position Switch

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