HVAC NATE HEAT PUMP
On70an70R-
2270system,70line70diameters70and70lengths70are70typically70specified70for70a70vapor70pre
ssure70drop70that70does70not70exceed70what?70-70answer--6-7PSI70or706F
What70is70the70primary70purpose70of70using70flux70when70soldering70copper70or70brass70
parts?70-70answer--Prevent70Oxidation
The70water70that70results70from70a70defrost70cycle70of70an70air70to70air70heat70pump(runo
ff)70must?70-70answer--Drain70off70and70away70from70the70outdoor70coil.
Why70must70the70runoff70be70drained70off70and70away70from70the70outdoor70coil?70-
70answer--
Excessive70ice70can70build70up70on70the70bottom70of70the70coil70and70can70reduce70capa
city.
What70is70the70component70that70reduces70sound70transmission70and70prevents70water7
0leaks70of70a70package70heat70pump70installed70on70a70roof?70-70answer--Curb70Gasket
Why70do70you70need70to70add70a70control70for70a70heat70pump70indoor70coil70that70is70in
stalled70on70a70fossil70fuel70furnace?70-70answer--
So70the70heat70pump70and70furnace70do70not70operate70at70the70same70time70in70normal
70heating.
What70happens70when70you70energize70a70hermetic70refrigeration70compressor70and70th
e70system70is70in70a70deep70vacuum?70-70answer--
Motor70windings70could70become70damaged.
What70needs70to70happen70in70order70to70consider70an70evacuation70to70be70complete?
70-70answer--
System70should70be70evacuated70to70a70vacuum70of7050070Microns70or70below.
A70system70is70supplied70from70the70factory70with70charge70for70a701570foot70line70set.70T
he70data70plate70shows70the70required70system70charge70to70be70570pounds701070ounce
s.70The70line70set70uses70a703/870inch70liquid70line70and70is702570feet70long.70The70manuf
acturer's70instruction70sheet70specifies700.670ounces70of70refrigerant70to70be70added70for
, 70each70added70foot70of70refrigerant70line70length.70How70much70refrigerant70is70needed7
0to70completely70charge70the70system?70-70answer--6lbs
Where70are70drive70slips70typically70installed?70-70answer--
On70the70shorter70sides70of70rectangular70duct.
What70is70a70necessary70check70to70properly70set70a70heat70anticipator?70-70answer--
Heating70control70circuit70amperage70
draw.
A70heat70pump70operating70in70normal70ice70free70conditions70maintains70a70certain70te
mperature70difference70between70the70outdoor70coil70temperature70and70the70surroundin
g70outdoor70ambient.70What70is70this70temperature70referred70to70as?70-70answer--
Coil70TD.
What70is70the70smallest70refrigerant70leak70that70an70electronic70leak70detector70should70
be70capable70of70sensing?70-70answer--.o5oz70per70year.
When70checking70the70pressures70in70an70operating70system70with70a70manifold70gauge7
0set,70will70refrigerant70oil70in70a70hose70will70have70an70effect70on70the70gauge?70-
70answer--No
What70is70the70absolute70pressure70at70sea70level70if70a70gauge70pressure70is703570psig?
70-70answer--49.7psia
100,00070BTUH70output70furnace.
Return70air70temp70is7065F.
Supply70air70is70135F.
What70is70the70CFM?70-70answer--1323CFM
What70is70the70best70method70of70repair70when70a70residential70supply70diffuser70is70nois
y70because70of70a70loose70vane?70-70answer--Replace70the70diffuser.
When70performing70preventive70maintenance70on70a70heat70pump70what70should70the70t
echnician70check70and70why?70-70answer--
Outdoor70fan.70To70be70certain70it70runs70freely70with70no70binding.
What70is70the70effect70of7017070volts70supplied70to70a70208/23070volt70compressor?70-
70answer--
Would70cause70the70current70to70increase70and70the70motor70may70trip70on70overload.
On70a70service70call70for70a70cooling70problem70with70a70heat70pump,70your70inspections
70find70a70liquid70line70that70has70condensation70on70it.70What70is70most70likely70to70caus
e70this?70-70answer--Restriction70in70the70liquid70line.
On70an70R-
2270system,70line70diameters70and70lengths70are70typically70specified70for70a70vapor70pre
ssure70drop70that70does70not70exceed70what?70-70answer--6-7PSI70or706F
What70is70the70primary70purpose70of70using70flux70when70soldering70copper70or70brass70
parts?70-70answer--Prevent70Oxidation
The70water70that70results70from70a70defrost70cycle70of70an70air70to70air70heat70pump(runo
ff)70must?70-70answer--Drain70off70and70away70from70the70outdoor70coil.
Why70must70the70runoff70be70drained70off70and70away70from70the70outdoor70coil?70-
70answer--
Excessive70ice70can70build70up70on70the70bottom70of70the70coil70and70can70reduce70capa
city.
What70is70the70component70that70reduces70sound70transmission70and70prevents70water7
0leaks70of70a70package70heat70pump70installed70on70a70roof?70-70answer--Curb70Gasket
Why70do70you70need70to70add70a70control70for70a70heat70pump70indoor70coil70that70is70in
stalled70on70a70fossil70fuel70furnace?70-70answer--
So70the70heat70pump70and70furnace70do70not70operate70at70the70same70time70in70normal
70heating.
What70happens70when70you70energize70a70hermetic70refrigeration70compressor70and70th
e70system70is70in70a70deep70vacuum?70-70answer--
Motor70windings70could70become70damaged.
What70needs70to70happen70in70order70to70consider70an70evacuation70to70be70complete?
70-70answer--
System70should70be70evacuated70to70a70vacuum70of7050070Microns70or70below.
A70system70is70supplied70from70the70factory70with70charge70for70a701570foot70line70set.70T
he70data70plate70shows70the70required70system70charge70to70be70570pounds701070ounce
s.70The70line70set70uses70a703/870inch70liquid70line70and70is702570feet70long.70The70manuf
acturer's70instruction70sheet70specifies700.670ounces70of70refrigerant70to70be70added70for
, 70each70added70foot70of70refrigerant70line70length.70How70much70refrigerant70is70needed7
0to70completely70charge70the70system?70-70answer--6lbs
Where70are70drive70slips70typically70installed?70-70answer--
On70the70shorter70sides70of70rectangular70duct.
What70is70a70necessary70check70to70properly70set70a70heat70anticipator?70-70answer--
Heating70control70circuit70amperage70
draw.
A70heat70pump70operating70in70normal70ice70free70conditions70maintains70a70certain70te
mperature70difference70between70the70outdoor70coil70temperature70and70the70surroundin
g70outdoor70ambient.70What70is70this70temperature70referred70to70as?70-70answer--
Coil70TD.
What70is70the70smallest70refrigerant70leak70that70an70electronic70leak70detector70should70
be70capable70of70sensing?70-70answer--.o5oz70per70year.
When70checking70the70pressures70in70an70operating70system70with70a70manifold70gauge7
0set,70will70refrigerant70oil70in70a70hose70will70have70an70effect70on70the70gauge?70-
70answer--No
What70is70the70absolute70pressure70at70sea70level70if70a70gauge70pressure70is703570psig?
70-70answer--49.7psia
100,00070BTUH70output70furnace.
Return70air70temp70is7065F.
Supply70air70is70135F.
What70is70the70CFM?70-70answer--1323CFM
What70is70the70best70method70of70repair70when70a70residential70supply70diffuser70is70nois
y70because70of70a70loose70vane?70-70answer--Replace70the70diffuser.
When70performing70preventive70maintenance70on70a70heat70pump70what70should70the70t
echnician70check70and70why?70-70answer--
Outdoor70fan.70To70be70certain70it70runs70freely70with70no70binding.
What70is70the70effect70of7017070volts70supplied70to70a70208/23070volt70compressor?70-
70answer--
Would70cause70the70current70to70increase70and70the70motor70may70trip70on70overload.
On70a70service70call70for70a70cooling70problem70with70a70heat70pump,70your70inspections
70find70a70liquid70line70that70has70condensation70on70it.70What70is70most70likely70to70caus
e70this?70-70answer--Restriction70in70the70liquid70line.
