Check Resistance - Graco Therm-O-Flow 20 EasyKey Instructions Manual

Check Resistance

Check the Resistance Between the Supply
Unit and the True Earth Ground
The resistance between the supply unit components
and true earth ground must be less than 0.25 ohms.
Have a qualified electrician check the resistance
between each supply unit component and the true earth
ground. The resistance must be less than 0.25 ohms. If
the resistance is greater than 0.25 ohms a different
ground site may be required. Do not operate the system
until the problem is corrected.
Use a meter that is capable of measuring resis-
tance at this level.
Sensor Resistance Checks
Conduct these electrical checks with the main discon-
nect OFF.
The package includes a heat sensor and controller for
each of the four heated zones. To check sensor resis-
tance:
1. Make sure the power is off and that the disconnect
switch is in the OFF position.
2. Make electrical resistance checks for the compo-
nents.
Zone
1
312094K
Table 3: Resistance Chart of All Heaters
Between
Component Terminals
Platen E to D, F to A
(without jumpers)
3L1 to 3L2
(with jumpers)
E to F, D to A
(with jumpers)
3L1 to 3L2
(with jumpers)
Any to Ground
3. Replace any parts whose resistance readings do
not comply with the ranges listed in Table 2.
Check resistance at ambient room temperature
(63°– 77°F [17°– 25°C]
Table 2: RTD Sensors
Zone Component
1 Platen
2 Dispense Hose 1
3 Dispense Gun 1
4 Dispense Gun 2
Heater Resistance Checks
Conduct these electrical checks with the main power
disconnect OFF.
To check heater resistance:
1. Make sure the power is off and that the disconnect
switch is in the OFF position.
2. Make electrical resistance checks for the compo-
nents. See Electrical Schematics on page 49 for
wiring diagram information.
3. Replace any parts whose resistance readings do
not comply with the ranges listed in Table 3.
Check resistance at ambient room temperature
°F) (
(63°– 77 17°– 25
Unit Resistance Values
Voltage
240V 28.8 +3/-4
240V 14.4 +1.5/-2
380V/480V 28.8 +3/-4
380V/480V 57.6 +6/-8
100,000 minimum
Installation
).
Terminals Range (ohms)
2011 & 2021 108 +/- 2%
2051 & 2061 108 +/- 2%
2081 & 2091 108 +/- 2%
2111 & 2121 108 +/- 2%
°C).
(ohms)
13