LeeBoy 8608 - Electric Heat Control Box; Element Resistance Testing

Maintenance
LeeBoy 8608 Commercial Paver5-28
ELECTRIC HEAT CONTROL BOXELECTRIC HEAT CONTROL BOX
The electric heat control box contains the element
breakers and main outputs for the screed heating
system. Powered at 240 VAC, each element has two
circuit breakers. (Figure 5-25)
1
2
3
4
5
9
6
7
8
10
Figure 5-25. Electric Heat Elements
1 - Power Control Relays
2 - Heating Element Relays
3 - Element Circuit Breakers
4 - Power Crown Switch
5 - Cycling Timer
6 - Automatic/Manual Power Toggle Button
7 - Toggle for Left/Right Endgates
8 - Wire Junction Block
9 - Manual Mode Timer
10 - Heat ON Button
ALWAYS be careful when working with
electrical components to avoid electrical shock. The
heat box is high voltage (220V), therefore, take extra
precautions to avoid electrical shock that could
cause serious injury or even death.
NOTE: Control boxes are manufactured to t all
screed and paver combinations. If not all
plugs are connected to wires, it may be
normal. Be sure to keep unused plugs
covered with mating protective caps.
• Each element output consists of two wires--one
connects to the L-1 circuit and the other to the L-2
circuit.
• Each breaker has two terminals--one is connected
to the main input and the other terminal to an element
output wire.
• The L-1 circuit is the left bank of element breakers.
• The L-2 circuit is the right bank of element breakers.
Heating element relays “make” or “break” the circuit
to each element to start or stop the heating cycles.
When the HEAT ON button is depressed, 12VDC is
momentarily applied to the main timer relay to start the
timing cycle.
Element Resistance TestingElement Resistance Testing
The breakers are wired into each leg of each element.
If an element has a fault, either in the wiring, or in the
element itself, the breaker will trip and power will no
longer be applied to that leg of the element.
When a breaker in the control box has “tripped,” there
may be a problem in the wiring or an element in the
circuit.
The breakers can be manually reset by depressing the
trip button back into place when they are extended. If
the breaker still does not reset, you need to test or
possibly replace an element.
If the element is functioning correctly, you should read a
resistance between the connector pins when testing. A
faulty element will show high resistance, indicating a bad
element.
To test the element:
1. Disconnect elements one at a time from the con-
nection point on the lower side of the control box,
keeping track of connector placement.