Graco 25D117, Операция

Страница: 13 / 50

Installation
3A5354B 13
Check Resistance
Check the Resistance Between the Supply
System and the True Earth Ground
Have a qualified electrician check the resistance
between each supply system component and the true
earth ground. The resistance must be less than 0.3
ohms. If the resistance is greater than 0.3 ohms, a dif-
ferent ground site may be required.
NOTE: Use a meter that is capable of measuring resis-
tance at this level.
Sensor Resistance Checks
NOTE: For dispense valve and hose sensor resistance
checks, refer to your dispense valve manual or hose
manual.
The supply system includes a heat sensor and controller
for each of the six heated zones. To check the sensor
resistance:
1. Make sure the power is off and the main power
switch (MP) is in the OFF position.
2. Make electrical resistance checks for the compo-
nents.
3. Replace any parts that have resistance readings
that do not comply with the ranges listed in Table 2.
NOTE: Check the resistance at ambient room tempera-
ture (63°– 77°F [17°– 25°C]
).
To reduce the risk of electric shock, the resistance
between the supply system components and true
earth ground must be less than 0.3 ohms. If the resis-
tance exceeds 0.3 ohms, perform the following steps:
•
Verify the grounding stud is correctly in place in the
electrical enclosure (see F
IG
. 11).
• Check the supply system resistance between
each supply system component and the grounding
stud.
• If the resistance exceeds 0.3 ohms after following
the previous steps, contact Graco technical sup-
port. Do not operate the system until the problem
is corrected.
F
IG
. 11: Grounding Stud
DB
To reduce the risk of electric shock, conduct electrical
checks with the main power switch (MP) OFF.
Table 2: RTD Sensor Resistance
Zone Component Connector Pin Range (ohms)
1 Platen Pin K and M
1050-1100
2 Fluid Pump Pin K and M
1050-1100
F
IG
. 12: RTD Connector Pins


A
B
C
D
E
F
G
H
J
K
L
M
Pin K
Pin M