How many wires are needed for a communicating control system to control a three-stage heat, two-stage cool heat pump?
A) Nine wires—one for each stage plus reversing valve and power
B) Five wires—one for each stage heat and cool
C) Four wires—two for power and two for communication
D) No wires are required because communicating systems are wireless.
C
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Technician A says that when performing a stall test on an Allison hydromechanical transmission he places selector in the DR position on a deep ratio model. Technician B says that on a four-speed hydromechanical Allison transmission a stall test can be safely performed with the selector in D2, D3 or D4 positions. Who is correct?
A. Technician A only B. Technician B only C. Both A and B D. Neither A nor B
The permanent discharge line on a reversing valve is always located:
A) In the middle on the side with three large lines. B) On the left on the side with three large lines. C) On the right on the side with three large lines. D) By itself opposite the side with three large lines.
If lumber is used in contact with masonry, it must be _____
a) secured with epoxy b) pressure-treated c) separated by a waterproof underlayment d) secured with finishing nails
Which of the following statements is incorrect?
A. O'rings come in a large variety of shapes. B. O'rings are identified by material, inner diameter, and cross-sectional areA. C. O'rings compression should not exceed 35% D. O'ring failure is usually not a result of installation mistakes, damaged O'rings, or grooves.