Specifications

530.25-N1
ECONOMIZER RAIN HOOD OPTION
The out do[)r and return alr dampers, the spring-return dan~-
per Jctuator, the linkage, the enthti]py c}mngeover control,
+ the rimed tiir temperature cxmtrol and the mmimum position
potentiometer with manual auto switc}] are factory mounted
as part of tbe economue[ optmn. The rain hood is shipped
m J separale package and must be assembled to the unit per
the assembly instructions in Form 530.25-N 1.4.
CAUTIO.}’ ,})ttwr~)peratethe unit )vi[hmf itz~tullingthe
hlxd or moisture will be duwn into the utlit.
FIXED OUTSIDE AIR RAIN HOOD
The fixed outdoor alr d~nlpet with i manual tidjustment arm
M t;Ict(~Iy mounted on all units without the economizer op-
tion. The rain h(md is shipped in I septir~te pachage and must
be assembled to the unit per the assembly instructions in
Form 530.25-N 1.3.
CA
UTIOI\’:Ifretreroperate the unit without instaflirrgrite
hood (v moistitre itif{ be draiivl it~tothe utlit.
EXHAUST Al R RAIN HOOD OPTION
The barometric exhaust dampers, the powered propeller ex-
haust fan and the damper motor end switch are factory m-
installedand wired as part of the exhaust olr option. The rain
hood ISshipped in a separate package and must be assembled
to the unit per the ~ssembly Instructions in FOIm 530.25-N 1.2
.L’0T15’ The exiraust hood (or tiw DSC 480 is shipped [Mtit-()
Patkages.
CAUTIOAF:I\relleroperate the utlit wtithouritlstallitlgthe
fmxr’or f~mist[trc\\[If bc drauw itlto the unit.
OPERATION
ELECTRO-MECHANICAL CONTROLS
The t)petat]on of these un]ts can be d]vided m!{) f{)uI systems.
1. Economi,w] System ( ~lpliorral)
2. 1leatlng Systcm (opt]~)ndl)
3. (’oo]]ng System
4. l:~haust Air (optmnal)
-
ECONOMIZER SYSTEM
The outside and the retul n air dampers are controlled by a
pIopoI tmnal type, m]xed-a]r cent]
o]ler( 1RI 1) which senses
the tempe]at u]e of the a]r leaving the evaporator coil. The
d~n]pers can modu]ate anywhe] e from theil mmmum out-
side pos~tion to 1OOV open in fltt empt ing to maintain the
tcmpelature setting of 1R11. If the indoor space temperature
rms, TC2 will close and the No. 1 compressor will be ener-
gi/ed through tbe 5R relay cont:ic(s to provide second stage
coohng,
The l:con[)n]]/er system c{)ns]stsof:
1 outdoor ~nd ret urn uu dampers.
2. Dampel Actuotor (Spring Return).
3. Enthalpy Contr[)] 5TII.
4, M]xed Air Controller” - I RI].
5. klm]mum oot Ndc
aII od]ustt~l (potent iometel ) - 2R11.
The Fct)nomller System provides ~be first st~ge ot c~~[)hng
whenever tile out side :111If COLJIand dI y enough to wt IS(y
the lnterrml ctwlIng demand. Tbe outsde and the Ieturn air
dampe]s aI e n]cchan]call~ linhed tind SIe modulated hy the
spIIII: return d;lmper actuutor. As the outside o]r clfin]pers
aIe t)pcned h~rtIIe CLIInpct actu;itol. the
IetUIn uir d~mper>
ale closed
When the entl~alpy c~)ntrol ( 5TI 1) sensesoutside
alt temp
erstures pel Table 5, thc out side air dampels close tt) theu
mmlmum pojit M)II. TIIC lninl mum positItJn ~>ftbe [)ut side
aII dampeIs is determlncd by tile wt p(~]nt (JFthe mm imum
t)ut$Ide .III adIustor ( ~Rt i) ](lc’lted In the tel mulal bt)~ 0[
the damper n]otol
TIw enlh:ilp) contl 01 ( 5-111)1~f~ctot Y set It sen~esboth
temperal ulc and humldlt }! :Ind \Jrie\ it~wt tlng so ,i$ t{) linl-
]t [he lnt roductIon ot’i~uts]de ;,lr. As notcd in Tab Ie 5 he]ow,
+
the c(~ntr~ll WI]! nt)t ~11(~~}(~ut>ldc:111[() cnt CI tbc unit
duI Ing
hlgl)
llumidl~y ulnd]t II~n\ e\ccpt it (i l~)weI [~ut~ldc tenlpela-
ture. DUI lng dry condl[ l(~n$.:111Is lnt I[)d
uLed at o Ili,ghel unl-
blent,
CES
TABLE 5 – ENTHALPY CONTROL (SET POINT “B”)
OUTDOOR DRY
I
%
R ELAT 1V E
BULB TEMP. “F
HUMIDITY
62
80
67
60
71
40
73 20
74
10
DAMPER LINKAGE ADJUSTMENT
Aft e] powe] IIVSbeen suppllecl to the unit. the out mle ~nd
Ietul n alr d~nlpeIs sht)ulclbe checked to nuike sure they
Opel:1[e II eel} and close tlghtly. I t my be necessary to re-
ad)tlst I be III] kage bet ween the ckrmpm motor and the blades
duc t(l Imlsenmg in shipment.
13