Turbo Chef Technologies 3240 manual If the coil resistance is incorrect, replace the

2 2 OVEN SYSTEMS

b) If terminal resistance is incorrect,	Testing Procedure
replace the power supply.	1. Disconnect line voltage to the unit.
3. If correct voltage is present, disconnect the	2. Take a resistance reading of the coil.
output wires and check output (-OUT &
	3. If coil resistance is correct (577 W):
+OUT) for 24 VDC.
4. If voltage is present with output wires	a) Apply line voltage to the unit.
	b) Check for 24 VDC at the coil of the
disconnected and not present when the
wires are connected, inspect the wire	relay when the unit is calling for heat.
harness for damage or shorts.	c) Check the state of the contacts.
5. If the wire harness is intact and undamaged,	-If the normally open contacts (7 & 4
	-or C & NO) are closed when coil
the power supply is damaged or defective
	-voltage is applied, the K3 relay is
and must be replaced (page A-8).
	-functioning normally.
Power Supply - 24VDC (International)	-If the normally open contacts (7 & 4
	-or C & NO are not closed when coil
The power supply - 24VDC (international)	-voltage is applied, the K3 relay is
converts line voltage to 24 VDC. Line voltage is	-malfunctioning and must be replaced
connected to terminals L & N. The output (24	-(page A-8).
VDC) is on terminals “-V” and “+V”.	4. If the coil resistance is incorrect, replace the
Testing Procedure	K3 relay.
1. Check for line voltage (208-240 VAC) at	K4 Relay - Ignition
terminals L & N.
	The K4 relay is a single pole, double throw
2. If correct voltage is present, check output
	relay with a 24 VAC coil. The coil resistance is
(-V & +V) for 24 VDC (with output wires	585 k W and the contact rating is 20 A at 240
disconnected).	VAC. When 24 VAC is applied to the coil, the
3. If voltage is present with output wires	normally open contacts (7 & 4 or C & NO)
	close and the normally closed contacts (7 & 1
disconnected and not present when the
	or C & NC) open.
wires are connected, inspect the wire
harness for damage or shorts (page 45).	The K4 relay uses the normally closed contacts.
4. If wire harness is intact and undamaged,	If 24 VAC is applied to the ignition module
	and 1.5 uA minimum is not maintained, the
the power supply - 24VDC (international)
	ignition module applies 24 VAC to the relay
is damaged or defective and must be
	and the contacts open. When the contacts open
replaced (page A-8).
	the I/O control board shows an “F3 No Flame”
K3 Relay - Gas	fault.

The K3 relay is a single pole, double throw relay with a 24 VDC coil. The coil resistance is 577 W and the contact rating is 20A at 240 VAC. When 24 VDC is applied to the coil, the normally open contacts (7 & 4 or C & NO) close applying line voltage to the burner trans- former and the combustion blower.

Testing Procedure

1.Disconnect line voltage to the unit.

2.Take a resistance reading of the K4 coil.