On low pressure chillers, moisture typically enters the refrigerant system through - ANSWER-air leaks
from areas with gaskets or fittings
The maximum test pressure for leak testing a low pressure centrifugal is: - ANSWER-10 psig
Leak test and repair the chiller to reduce refrigerant loss from a pruge unit on CFC-11 chiller -
ANSWER-...
A hydrostatic tube test kit is used to: - ANSWER-determine if a tube leaks
Commercial and industrial process refrigeration systems must be repaired when the leak rate exceeds
____ of the charge per year. - ANSWER-35%
Refrigerant recovery typically start with liquid recovery it is faster. - ANSWER-...
A rupture disc on a recovery vessel for a low pressure refrigerants relieves at: - ANSWER-15 psig
According to ASHRAE Guideline 3-1996, if the pressure in a system rises from 1 mm Hg to a level above
____ during a standing vacuum test, the system should be checked for leaks. - ANSWER-2.5 mm Hg
The primary water source for a recovery unit condensing coil is _____. - ANSWER-local municipal water
supply
When recharging a refrigeration system with R-11, what vaporpressure is necessary in the shells before
changing with liquid? - ANSWER-16.9" Hg vacuum
After recovering the liquid refrigerant you must: - ANSWER-recover the vapor refrigerant
, According to the EPA there is approximately _____ refrigerant vapor left in an average 350 ton R-11
chiller at 0 psig pressure once all the R-11 liquid has been removed. - ANSWER-100 pounds
Charging refrigerant liquid into a refrigeration system when it is under a 29 inch Hg vacuum can cause
the: - ANSWER-system water to freeze
A system does not have to be evacuated all the way to the required level when: - ANSWER-leaks in the
appliance make evacuation to the prescribed level unattainable
Which of the foloowing repairs would ALWAYS be considered "major" under EPA's - ANSWER-
replacement of evaporator coil
Under EPA's regulation's _______ is used to pressurize a low pressure chiller for the purpose of opening
the system for a non major repair? - ANSWER-warming the refrigerant
If you are using a recovery machine manufactored AFTER 11-15-93 you must evacuate an low pressure
appliance to _______ before making a major repair. - ANSWER-25 mm of Hg absolute
After reaching the required recovery vacuum on a chiller, you should - ANSWER-Wait for at least a few
minutes to see if the system pressure rises, indicating that there is till refrigerant in a liquid form or in
the oil
The pressure corresponding to 32 F for R-123 - ANSWER-20 inches of HG vacuum
When evacuating a system the use of too large a vacuum pump can cause? - ANSWER-trapped water to
freeze
Refrigerant-11 at a pressure of 17 inches HG vacuum has a saturation temperature of: - ANSWER-35F
During the evacuation of a system containing large amounts of moisture you can prevent freezing of this
moisture by increasing the pressure with______gas - ANSWER-nitrogen