Written Z51 Questions with Correct
Answers 2025/2026
wing. Ya Ymore Yefficient Ycentrifugal Ycompressor Yoperation Yresults Yfrom: Y- YCORRECT
YANSWER Y- YLowering Ythe Ycondensing Ypressure
The Yheat Yremoved Yfrom Ythe Yrefrigerant Yin Ya Ycondenser Yis: Y- YCORRECT
YANSWER Y- YSensible Yand Ylatent Yheat
The Yrefrigerant Yunit Ythat Yyou Yhave Ybeen Yassigned Yto Yis Ybeing Ytaken Yout Yof Yservice Yfor
Ya Ymajor Yre Ypair. Yyou Yhave Ybeen Yassigned Yto Ywithdraw Yrefrigerant Yfor Ystorage Yin
Ysuitable Ycontainers. Yaccordi Yng Yto Ythe Ynew YYork Ycity Yfire Ycode, Yyou Ymust Yensure Ythat
Ythe Ycontainers: Y- YCORRECT YANSWER Y- YAre Yapproved Yby Ythe YUS Ydepartment Yof
Ytransportation
Which Yof Ythe Yfollowing Ybest Ydescribes Yhow Ythe Ycylinder Yunloader Ywork? Y- YCORRECT
YANSWER Y- YKeep Yin Ythe Ysuction Yvalve Yopened Ywhile Ythe Ycompressor Yis Yin Ythe Yreturn
Ystroke
In Ymost Ysemi Yhermetic Ycompressors, Ythe Ysuction Yvapor Yis Yused Yto: Y- YCORRECT
YANSWER Y- YCool Ythe Ymotor
The Yamount Yof Yrefrigerant Ythat Yflows Ythrough Ythe Yorifices Yof Ya Yeconomizer Yis Ydetermined
Y by Ythe
: Y- YCORRECT YANSWER Y-Difference Ybetween Ythe Yhigh Yside Yand Yload Yside Ypressure
The Yinstallation Yof Yan Yinline Yrefrigerant Ycleaning Ysystem Yis Yadvisable: Y- YCORRECT
,YANSWER Y- YTo Yremove Yimpurities Yfrom Ythe Ysystem
The Ytype Yof Yrefrigerant Ysystem Ythat Yis Yleast Ylikely Yto Yleak Yrefrigerant Yinto Ythe Ybuilding
Yspace Ythat Yare Ycooled Y- YCORRECT YANSWER Y-The Yindirect Ysystem
, The Ysuction Ypressure Yof Ya Yreciprocating Ycompressor Yis Y65PSIG. Ythe Ydischarge Ypressure
Yof Ythis Yco Ympressor Yis Y120PSIG. Ythe Yatmospheric Yis Y14.7 YPSI. Ythe Ycompression Yratio
Yfor Ythe Ygiven Ycondition Yis Ycloset Yto: Y- YCORRECT YANSWER Y-1.69
A Ysuper Yheated Yvapor Yis Ya Y? Y- YCORRECT YANSWER Y-Dry Yvapor Yabove Ythe Ysaturation
Y temperature
A Yrefrigerant Yengineer Yverifies Ythat Ya Ycondenser Ywater Ypump Yis Ycavitating. Yof Ythe
Yfollowing Ythe Ymost Ylikely Ycause Yfor Ythis Ycondition Yis: Y- YCORRECT YANSWER Y-
A Yfaulty Ycooling Ytower Ywater Ylevel Ycontroller
A Ycentrifugal Ywater Ypump Yis Yknown Yas Ya Ylift Ypump Ywhen Ythe: Y- YCORRECT
YANSWER Y- YThe Ywater Ysupply Yto Ythe Ypump Ysuction Yinlet Yis Ybelow Ythe Ypump
Ylevel
A YTXV Yis Yused Yto Ymaintain Yconstant: Y- YCORRECT YANSWER Y-Evaporator Ysuperheat
The Ychilled Ywater Ysupply Yto Ythe Ybuilding Yis Y55F. Yif Ythe Ychiller Yis Ybeing Yused Yfor
Yhuman Ycomfort, Ys Yhould Yyou Ybe Yconcerned Yabout Ythis Y, Yand Ywhy? Y- YCORRECT
YANSWER Y-
Yes, Ythis Ytemperature Yis Ytoo Yhigh Yfor Yhuman Ycomfort Ypurpose
The Ypacking Ygland Yof Ya Ycentrifugal Ypump Yserves Yto: Y- Y CORRECT YANSWER Y-
The Ydrip Ypart Yof Y the Ypacking Ygland Y gives Yevidence Ythat Ythere Yis Ywater Yin Ythe Ypump
Capacity Ycontrol Yof Ya Yreciprocating Yhermetic Ycompressor Yis Ytypically Yachieved Ythrough Y-
YCORRECT YANSWER Y-Operation Yof Ythe Yhot Ygas Ybypass Yvalve
The Ymost Yimportant Yreason Yto Ysub-cool Ythe Yrefrigerant Yin Ythe Ycondenser Yis Yto Yensure
Ythat: Y- YCORRECT YANSWER Y-A Ypure Yliquid Yrefrigerant Ywill Yenter Ythe Ymetering Ydevice
Answers 2025/2026
wing. Ya Ymore Yefficient Ycentrifugal Ycompressor Yoperation Yresults Yfrom: Y- YCORRECT
YANSWER Y- YLowering Ythe Ycondensing Ypressure
The Yheat Yremoved Yfrom Ythe Yrefrigerant Yin Ya Ycondenser Yis: Y- YCORRECT
YANSWER Y- YSensible Yand Ylatent Yheat
The Yrefrigerant Yunit Ythat Yyou Yhave Ybeen Yassigned Yto Yis Ybeing Ytaken Yout Yof Yservice Yfor
Ya Ymajor Yre Ypair. Yyou Yhave Ybeen Yassigned Yto Ywithdraw Yrefrigerant Yfor Ystorage Yin
Ysuitable Ycontainers. Yaccordi Yng Yto Ythe Ynew YYork Ycity Yfire Ycode, Yyou Ymust Yensure Ythat
Ythe Ycontainers: Y- YCORRECT YANSWER Y- YAre Yapproved Yby Ythe YUS Ydepartment Yof
Ytransportation
Which Yof Ythe Yfollowing Ybest Ydescribes Yhow Ythe Ycylinder Yunloader Ywork? Y- YCORRECT
YANSWER Y- YKeep Yin Ythe Ysuction Yvalve Yopened Ywhile Ythe Ycompressor Yis Yin Ythe Yreturn
Ystroke
In Ymost Ysemi Yhermetic Ycompressors, Ythe Ysuction Yvapor Yis Yused Yto: Y- YCORRECT
YANSWER Y- YCool Ythe Ymotor
The Yamount Yof Yrefrigerant Ythat Yflows Ythrough Ythe Yorifices Yof Ya Yeconomizer Yis Ydetermined
Y by Ythe
: Y- YCORRECT YANSWER Y-Difference Ybetween Ythe Yhigh Yside Yand Yload Yside Ypressure
The Yinstallation Yof Yan Yinline Yrefrigerant Ycleaning Ysystem Yis Yadvisable: Y- YCORRECT
,YANSWER Y- YTo Yremove Yimpurities Yfrom Ythe Ysystem
The Ytype Yof Yrefrigerant Ysystem Ythat Yis Yleast Ylikely Yto Yleak Yrefrigerant Yinto Ythe Ybuilding
Yspace Ythat Yare Ycooled Y- YCORRECT YANSWER Y-The Yindirect Ysystem
, The Ysuction Ypressure Yof Ya Yreciprocating Ycompressor Yis Y65PSIG. Ythe Ydischarge Ypressure
Yof Ythis Yco Ympressor Yis Y120PSIG. Ythe Yatmospheric Yis Y14.7 YPSI. Ythe Ycompression Yratio
Yfor Ythe Ygiven Ycondition Yis Ycloset Yto: Y- YCORRECT YANSWER Y-1.69
A Ysuper Yheated Yvapor Yis Ya Y? Y- YCORRECT YANSWER Y-Dry Yvapor Yabove Ythe Ysaturation
Y temperature
A Yrefrigerant Yengineer Yverifies Ythat Ya Ycondenser Ywater Ypump Yis Ycavitating. Yof Ythe
Yfollowing Ythe Ymost Ylikely Ycause Yfor Ythis Ycondition Yis: Y- YCORRECT YANSWER Y-
A Yfaulty Ycooling Ytower Ywater Ylevel Ycontroller
A Ycentrifugal Ywater Ypump Yis Yknown Yas Ya Ylift Ypump Ywhen Ythe: Y- YCORRECT
YANSWER Y- YThe Ywater Ysupply Yto Ythe Ypump Ysuction Yinlet Yis Ybelow Ythe Ypump
Ylevel
A YTXV Yis Yused Yto Ymaintain Yconstant: Y- YCORRECT YANSWER Y-Evaporator Ysuperheat
The Ychilled Ywater Ysupply Yto Ythe Ybuilding Yis Y55F. Yif Ythe Ychiller Yis Ybeing Yused Yfor
Yhuman Ycomfort, Ys Yhould Yyou Ybe Yconcerned Yabout Ythis Y, Yand Ywhy? Y- YCORRECT
YANSWER Y-
Yes, Ythis Ytemperature Yis Ytoo Yhigh Yfor Yhuman Ycomfort Ypurpose
The Ypacking Ygland Yof Ya Ycentrifugal Ypump Yserves Yto: Y- Y CORRECT YANSWER Y-
The Ydrip Ypart Yof Y the Ypacking Ygland Y gives Yevidence Ythat Ythere Yis Ywater Yin Ythe Ypump
Capacity Ycontrol Yof Ya Yreciprocating Yhermetic Ycompressor Yis Ytypically Yachieved Ythrough Y-
YCORRECT YANSWER Y-Operation Yof Ythe Yhot Ygas Ybypass Yvalve
The Ymost Yimportant Yreason Yto Ysub-cool Ythe Yrefrigerant Yin Ythe Ycondenser Yis Yto Yensure
Ythat: Y- YCORRECT YANSWER Y-A Ypure Yliquid Yrefrigerant Ywill Yenter Ythe Ymetering Ydevice
