Bryant FA4A - Manual (Page 25)

A U G / 1 4 / 2 0 0 8 / T H U 0 3 : 5 1 UTC TECH PUB F A X N o , 3 1 7 2 4 0 5 6 6 2 7 0 2 5
A94127
Fig. ; £ 2 — P i ' i n t e d - C i r ' c u i t Board (PCB)
tl.
3. A fuse is used to protect low-voltage transformer and PCB,
4. AUX+ and AUX- are connections for air.4 conditioning
accessories (EAC, humidifier, etc.).
5- FI, F2, HI, and LO arc connections for indoor fan.
6, The 9-pin receptacle connects heater package wiring har­
ness.
7, SECl and SEC2 are used to connect secondary side of
transformer to PCB. SECf is connected to equipment
ground,
UNIT FUNCTIONS
A. Transformer
NOTE: Terminals Tl, T2 (^if used), and T3 are wired to primary
or hi^h side of tr^nsfqmer.'The ^08-v tqrininal ‘(br blue wire'jf
transformer Has‘ primary lfeads) is on
2D8^^^applica-’'"
tjons, The 230-v tcoiimal (t;>r red witt) i$ iisAa^on'i’3'tpr 23Q-v
applications, T2 is a dummy terminal. 'i ■'■■i > ■
B. Electric Heat
NOTE: When troubleshooting dements, position thermostat to
emergency heat. Wait approximately 12 minutes for all elements to
come On,
1. When thermostat calls for electric heat, a 24-v signal is sent
to PCB through W2T, The PCE energizes first stage of
electric heat.
TABLE 7—ELECTRIC
2. The first 2 stages come on if WZT and Y are energized at
the same time. After each 10 minutes W2T iiS energized,
another stage of electric heat is energized.
3. As W2T is de-energized, electric heat, stages down in S
minute steps with the exception of first step. The first step
will be on only half as long as -it was prior to W2T
de-energizing.
- y - . ,
4. When W2T is energized by itself, JWl is cut, and an
outdoor thermostat is used and is open, staging is limited as
in Table 7,
5. When bAlh. W3 and W2T are energized without JWl being
cut'or with outdoor thermostat closed, system operation
.! stagesdieat up to maximum level if signal is energized for
ргоры gpiouhi:_pf .time,
6/ If'órilyFW3 is energized, there is no effect on PCE, No heat
.iS'^nergiicid..
C. Acces^Órics
Terminals AU^-t- and AUX- áre energized with 24 vdc when fan
is energizetl. The accessbry kit KFAIROIOIACR is used to
connect'aii EAC or'humidifier.
NO.TjE: "Loads cannot^be connected directly to AUX+ and AUX".
Us,e the specified kit only.
D. Blower
1. Blower On Dclay—To optimize comfort, there is a 30-sec
blower on delay in heat pump heating mode only.
HEATER STAGE LIMITING
HEATER PART NO.
STAGES (KW OPERATING)
W2T Only (JW1 cut) W 2 T and W3
Heater Stage 1 2 3 4
KPAFH22Q1H1Q 10 kw Non-Fuaed 3 6 9 9
KFAEH2301H15 15 kw Fused 3 8 11 15
KFAEH2401H20 ЙО kw Fused 6 10 15 20
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