Frymaster UHC-HD manual Tests 2.5.1 Power Supply, 2.5.2 RTD, Distribution Boards

Cabinet Service Procedures

•ERR LED toggles when a communication error is detected; it’s not unusual to see a flash, but regular flashing means communications problems.

•LED5 and LED6 used for programming/debugging; have no diagnostic function.

•LED7 When lit, the master control is executing a time or temp query operation on the front side.

•LED8 When lit, the master control is executing a time or temp query operation on the back side.

Distribution Board

•HB LED is a heartbeat LED; toggles on / off to indicate processor is running.

•ACT LED flashes when it receives a valid communication packet; it should be flashing every few seconds or faster.

•LED3 Toggles if there is a communications error on a packet directed to the distribution board. Can flash on occasion; shouldn’t flash regularly.

•LED1 flashes if there is voltage being applied to one or more heaters on that distribution board; one or more plate is calling for heat.

Fig. 5: Distribution Board LED's

2.5 Tests

2.5.1 Power Supply

1.Disconnect power and check all terminals and connections for loose or disconnected wires.

2.Apply power and check for 5VDC at the power-in terminal on the distribution board and chassis ground.

2.5.2 RTD

1.Remove the leads from the suspect RTD and test for resistance. Selected temperatures and resistances are show in chart at right.

NOTE: After testing, reconnect all leads to their original positions.

2.5.3 Distribution Boards

1.Check for line voltage between the heater plate terminal on the board and the terminal block for the

Sensor	Resistance	Sensor
(°F)		(°C)
60	106.065	15.55
70	108.224	21.11
80	110.380	26.66
90	112.532	32.22
100	114.680	37.77
110	116.825	43.33
120	118.966	48.88
130	121.104	54.44
140	123.239	60.00
150	125.369	65.55
160	127.496	71.11
170	129.620	76.66
180	131.740	82.22
190	133.856	87.77
200	135.969	93.33
210	138.078	98.88
220	140.184	104.44
230	142.286	110.00
240	144.385	115.55
250	146.480	121.11
260	148.570	126.66

RTD resistance chart

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