Blog

Which of the following is NOT a symptom of a hermetic system that is low on refrigerant?

When testing the efficiency of an air cooled condenser, the refrigerant condensing temperature should be approximately _____ higher than the entering air temperature.

The state of refrigerant in the suction line should be:

The method of defrost that involves circulating a hot liquid in and around the evaporator is _____ defrosting.

A partially iced over evaporator can be caused by_________.

When evaporator temperature cut-out point is reached in a system with pump-down defrost, the thermostat opens the circuit controlling a pump-down solenoid valve in the liquid line.

In a direct expansion (DX) evaporator system, the refrigerant enters the evaporator as______________.

A low refrigerant charge in an air conditioning system will cause___________.

COMMUNITY TESTLET: Use the following testlet to answer questions 41-45.  RESEARCH QUESTION: Which pre-procedural mouth rinse is more effective in reducing bleeding during NSPT, Chlorhexidine (CHX), hydrogen peroxide, or the placebo, salt water (saline solution). HYPOTHESES: A) There is no difference between CHX and hydrogen peroxide. B) There is a difference between CHX and hydrogen peroxide, patients rinsing with CHX will have the least amount of bleeding.  METHODOLOGY: In a double-blind study, SCC students between the ages of 18-21 were the subjects (ages = 19, 18, 19, 21,20, 19, 20, 19, 20, 20, 19). Each participant was randomly assigned to the CHX, hydrogen peroxide, or placebo group. The study was conducted over 4 weeks, 1 quad evaluated per week using the O’Leary Bleeding Index. Each participant rinsed with 5mL of their assigned mouth rinse 15 min prior to treatment.  RESULTS: A parametric test was used to determine if there was a statistically significant difference between the rinses. The results showed an overall statistically significant reduction in bleeding using CHX (p < 0.03). Additionally, an r-value of - 0.87 demonstrates a measure of correlation between bleeding and use of CHX. 42.    What would be the mode from this list of participant ages?a.    18b.    19c.    20d.    21

 Fin-and-tube evaporators circulating the most common types of refrigerants generally have fins made of _____.