Lennox Signature Collection XP15 Installation Instructions Manual page 15

valves, t urnoffthevacuum pump anddisconnect the
manifold gauge centerporthose fromvacuum pump.
Attachthemanifold centerporthosetoa drynitrogen
cylinder withpressure regulator setto 150psig(1034
kPa)andpurgethe hose.Openthe manifold gauge
valvestobreakthevacuum in thelinesetandindoor
unit.Close themanifold gaugevalves,
7, Shutoff the dry nitrogencylinderand removethe
manifold gaugehosefromthe cylinder. O penthe
manifold gauge valves torelease thedrynitrogen f rom
thelinesetandindoor u nit,
8, Reconnect themanifold gauge to thevacuum pump,
turnthepump on,andcontinue t oevacuate t helineset
andindoorunituntilthe absolute pressure doesnot
riseabove 500microns ( 29.9 inches ofmercury) within
a 20-minute p eriod aftershutting offthevacuum pump
andclosing themanifold gaugevalves.
9, Whenthe absolute pressure requirement abovehas
beenmet, disconnect the manifold hosefrom the
vacuum pumpandconnect it to anupright cylinder of
HFC-410A r efrigerant, Openthemanifold g auge valve
1 to2 psig inorder t orelease thevacuum inthelineset
andindoor u nit,
10, Close manifoldgauge valvesand shut off the
HFC-410A cylinder a ndremove the manifold gauge
set,
SERVICING UNITS DELIVERED V OIDOFCHARGE
If thesystem isvoidofrefrigerant, clean thesystem using
theprocedure d escribed b elow,
1, Usenitrogen topressurize t hesystem andcheckfor
leaks, R epair a llleaks,
2, Evacuate the systemto removeas muchof the
moisture aspossible,
3, Usenitrogen to breakthevacuum andinstall a new
filterdrierinthesystem.
4, Evacuatethe system again. Then, weigh the
appropriate a mount o f HFC-410A r efrigerant as listed
on unitnameplate i ntothesystem.
5, Monitorthe systemto determinethe amountof
moisture remaining i n theoil.It maybenecessary t o
replacethefilter drierseveral t imesto achievethe
required drynesslevel.If systemdryness is not
verified,the compressorwill fail in the future.
IMPORTANT
1. Rotate fan to check for frozen bearings or binding.
2, Inspect all factory- and field-installed wiring for loose
connections.
3, After evacuation is complete, open the liquid line and
vapor line service valves to release the refrigerant
charge (contained in outdoor unit) into the system,
4, Replace the stem caps and tighten as specified in
Operating Service Valves on page 3.
5, Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit's
nameplate. If not, do not start the equipment until you
have consulted with the power company and the
voltage condition has been corrected,
6, Set the thermostat for a cooling demand. Turn on
power to the indoor indoor unit and close the outdoor
unit disconnect switch to start the unit.
7, Recheck voltage while the unit is running. Power must
be within range shown on the nameplate,
8, Check system for sufficient refrigerant by using the
procedures listed under Testing and Charging
System,
TESTING AND CHARGING SYSTEM
This system uses HFC-410A refrigerant which operates at
much higher pressures than HCFC-22. The pre-installed
liquid line filter drier is approved for use with HFC-410A
only, Do not replace liquid line filter drier with components
designed for use with HCFC-22,
NOTE - This unit is NOT approved for use with coils which
use capillary tubes as a refrigerant metering device,
SETTING UP TO CHECK CHARGE
1. Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of HFC-410A.
2. Connect the manifold gauge set to the unit's service
ports as illustrated in figure 25,
• low pressure gauge to vapor service port
• high pressure gauge to liquid service port
COOLING MODE INDOOR AIRFLOW CHECK
Check airflow using the Delta-T (DT) process as illustrated
in figure 26 on page 16.
HEATING MODE INDOOR AIRFLOW CHECK
Blower airflow (CFM) may be calculated by energizing
electric heat and measuring:
• temperature rise between the return air and supply air
temperatures at the indoor coil blower unit,
• voltage supplied to the unit,
• amperage being drawn by the heat unit(s),
Then, apply the measurements taken in following formula
to determine CFM:
CFM =
Amps x Volts x 3.41
1.08 x Temperature rise (F)
CALCULATING CHARGE
If the system is void of refrigerant, first, locate and repair
any leaks and then weigh in the refrigerant charge into the
unit, To calculate the total refrigerant charge:
Additional charge
Amount Adjust amount for specified per
specified variation in indoor unit
on line set length match-up Total
nameplate (table in figure 27) (tables 6 through 11) charge
+ + =
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XP15 SERIES