List the operational sequence for the second stage of Figure 39-34. Just list what happens when the W2 terminal is energized
What will be an ideal response?
The second stage heating thermostat TSH2 closes to send 24 volts from R to W2, energizing heat sequencer HS1, line 18. The HS1 coil is a small heater that warps a bimetal disk to close the contacts after a time delay of 30 seconds. HS1 has two sets of normally open contacts that close after a time delay to prevent the strips from energizing immediately at startup when the compressor and fan motors are drawing high starting amps. The HS1 normally open contacts close, energizing the first heater HTR1and
the coil to the second heat sequencer HS2, lines 1 and 2. HS2 closes its contacts after a time delay to energize the second heater HTR2, line 3. Note that HS1 and HS2 normally open contacts in parallel with the IFR contacts, lines 10 and 12. They insure that the indoor fan motor will operate whenever the heat strips are operating.
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The United States uses which of the following standard systems of wire sizes?
a. Manufacturer’s Gauge b. Manufacturer’s Foundation c. American Wire Gauge d. International Electrotechnical Commission
Which of the following is NOT a strength of the quantitative planning tools discussed in
the text?
a. They can bring sophisticated mathematical techniques to bear on planning problems. b. They are able to accurately reflect situations that currently exist. c. They force managers to lo ok beyond their own preconceived ideas and biases. d. New and better computers are making sophisticated planning techniques more widely available. e. They help decision makers “see reason.”
Refrigerant traps are designed to aid in the return of __________ to the compressor.
A. cooling B. heating C. oil D. water
Select the characteristics of cubed ice. You may select more than one
A) 95 percent hardness B) Cloudy C) Slower melting D) Clear E) 70 percent hardness F) Faster melting