Relay, Solid State - K5/K4 Heaters; Rtd - TurboChef 2020 Service Manual

2 2 O V E N S YS T E M S
Testing Procedure
1. Disconnect line voltage to the unit.
2. Take a resistance reading of the coil.
3. If coil resistance is correct (585 W):
a) Apply line voltage to the unit.
b) Check for 24 VDC at the coil of the
relay when the unit is calling for heat.
c) Check the state of the contacts.
-If the normally open contacts (7 & 4
-or C & NO) are closed when coil
-voltage is applied, the relay is
-functioning normally.
-If the normally open contacts (7 & 4
-or C & NO are not closed when coil
-voltage is applied, the relay must be
replaced (page A-7 and A-8).
4. If the coil resistance is incorrect, replace the
relay.

Relay, Solid State - K5/K4 Heaters

The solid state relay is a 240 VAC, dual 40-amp
relay, and switches power to the heaters.

RTD

The RTD is a resistance temperature detector
used to detect the cavity temperature.
Testing Procedure
1. Disconnect the RTD from the I/O control
board.
ºF 0º
0º 90.03W
+200º 135.97W
+400º 177.47W
+600º 217.54W
ºC 0º
0º 100.00W
+100º 138.50W
+200º 175.84W
+300º 212.02W
Figure 32: Temperature/Resistance Relationship Class B. Resistance @ 0ºC = 100.0, Alpha = 0.003850
+20º +40º +60º
97.39W 101.74W 106.07W
140.18W 144.38W 148.57W
181.54W 185.60W 189.64W
221.47W 225.38W 229.28W
+10º +20º +30º
103.90W 107.79W 111.67W
142.29W 146.06W 149.82W
175.91W 183.17W 186.82W
215.57W 219.12W 222.65W
2. Place the RTD in a bowl of ice water for 2
minutes.
3. Take a resistance reading of the RTD.
4. If RTD resistance is not 100 W, RTD is
defective and must be replaced.
NOTE: Use Figure 32 to determine resistance
readings at temperatures other than freezing.
Smart Card Reader
The smart card reader allows the oven operator
to load a menu/firmware update from a smart
card. A menu that already exists in the oven can
also be saved to a smart card. For instructions,
see page 15.
Speaker
The speaker is separate from the control board,
and provides audible feedback to the oven oper-
ator whenever a key is pressed or a fault occurs.
Thermostats - 120ºF (Close on Rise)
The cooling fan thermostats actuate the cooling
fans when the temperature in either end bell
reaches or exceeds 120ºF (49ºC).
Wire Harness
The wire harness distributes power to the oven's
electrical components. See pages 37-40 for
schematics.
+80º +100º +120º
110.38W 114.68W 118.97W
152.74W 159.90W 161.04W
193.67W 197.69W 201.69W
233.17W 237.04W 240.90W
+40º +50º +60º
115.54W 119.40W 123.24W
153.58W 157.31W 161.04W
190.45W 194.07W 197.69W
226.17W 229.67W 233.17W
+140º +160º +180º
123.24W 127.50W 131.74W
165.17W 169.29W 173.39W
205.67W 209.64W 213.60W
244.74W 248.57W 252.38W
+70º +80º +90º
127.07W 130.89W 134.70W
164.76W 168.46W 172.16W
201.29W 204.88W 208.45W
236.65W 240.13W 243.59W
+200º
135.97W
177.47W
217.54W
256.18W
+100º
138.50W
175.84W
212.02W
247.04W