What are the various advantages associated with air inflation of a double layer of polyethylene as opposed to earlier methods of applying two layers of polyethylene?
What will be an ideal response?
Both layers can be applied from the outside of the greenhouse which
makes the process easier and quicker. The outer layer rests on a cushion of air
which results in a longer life expectancy, commonly three to four years. Often the
dead air space is a more uniform and desirable thickness leading to greater savings
in fuel. During a snowstorm the pressurizing fan can be turned off to allow the
layers of film plastic to touch and thereby loose heat faster for melting snow.
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Answer the following statement(s) true (T) or false (F)
1. The overload unit contacts are connected in parallel with the motor starter contactor unit control coil. 2. Electronic type of thermal overload units are adjustable for a range of motor load currents, and are set for the full load amperes (FLA) of the specific motor load. 3. When the melting alloy is a solid, the shaft of the ratchet wheel is held from turning. 4. When the bimetallic strip is heated, the metal with the lower thermal expansion characteristic will become longer, and cause the metal strip to bend.
The ____ is used to make a quick determination about whether the charging system is working properly.
A. voltage output test B. visual inspection C. no-load test D. load test
The first check to make whenever working on a water-cooled system is:
A) Compressor amp draw. B) Outdoor ambient wet bulb temperature. C) Condenser water flow. D) System operating pressures.
Vapor is more dense than liquid and, as the liquid refrigerant boils, it has a tendency to sink.
Answer the following statement true (T) or false (F)