sequence of
oper
ation
DRAIN PAN
PUMP
RESERV
OIR
BR
EAT
HER
TU
BE
DRAIN PAN
PUMP
RESERV
OIR
BR
EAT
HER
TU
BE
PUMP
DRAIN PAN
ATMOSPHERI
C
PRESSURE
RESERV
OIR
BR
EAT
HER
TU
BE
DRAIN PAN
PUMP
RESERV
OIR
BR
EAT
HER
TU
BE
DRAIN PAN
RESERV
OIR
BR
EAT
HER
TU
BE
MINIMUM
6”
MA
XI
MUM 2”
3/
4”
PV
C OR
COPPER PI
PE
PUMP
AI
R GAP
DRAIN PAN
MINIMUM
6”
MA
XI
MUM 2”
3/
4”
PV
C OR
COPPER PI
PE
PUMP
AI
R GAP
RESERV
OIR
BR
EAT
HER
TU
BE
DRAIN PAN
ATMOSPHERIC
PRESSURE
MINIMUM
6”
MA
XI
MUM 2”
3/
4”
PV
C OR
COPPER PI
PE
PUMP
AI
R GAP
ATMOSPHERIC
PRESSURE
RESERV
OI
RB
RE
AT
HER
TU
BE
DRAIN PAN
MINIMUM
6”
MA
XI
MUM 2”
3/
4”
PV
C OR
COPPER PI
PE
PUMP
AI
R GAP
RESERV
OIR
BR
EAT
HER
TU
BE
2
1
4
3
2
1
4
3
1.
Drain pan fills with water which flows into reservoir
.
Intake hose between reservoir and pump is empty (filled with air).
2.
Rising water lifts float activating pump, which self primes
by drawing water up from reservoir
. During this period the
pump is operating hot and dry and will click loudly
. Once
the air in the intake hose has been purged, water entering the pump cools and lubricates it so that the clicking noise becomes a low hum. W
ater flows through the pump and out
of the discharge hose.
3.
W
ater level in the reservoir has now receded enough to
drop the float, deactivating the pump. However
, the weight
of the water in the discharge hose plus atmospheric pres- sure at the drain pan outlet forces the water remaining in the intake hose to continue flowing out through the pump until the reservoir
, intake hose, pump and discharge hose
are completely empty
, at which point the siphoning stops.
4.
As the evaporator produces more condensate, the drain
pan again fills up with water which flows into the reservoir
.
Since the intake hose is filled with air again, the cycle repeats itself.
RESUL
T: EVER
Y
TIME
THE PUMP
RUNS HOT
AND DR
Y, IT
SUST
AINS
A
SMALL
AMOUNT
OF DAMAGE WHICH
CAUSES PREMA
TURE WEAR.
THE NEXT
TIME
THE PUMP
ST
AR
TS UP
DR
Y, IT
MA
Y RUN FOR 1
1 SECONDS
BEFORE IT
COOLS DOWN,
THE NEXT
TIME 12 SECONDS
AND SO ON.
ALSO, WHILE
THIS IS OCCURRING,
THE PUMP
IS CLICKING LOUDL
Y.
THIS IS
ACCEPT
ABLE DURING
THE
INITIAL
ST
AR
T UP
PHASE, BUT
NOT
ACCEPT
ABLE DURING SUBSEQUENT
OPERA
TIONS OF
THE PUMP
.
WHEN
YOU CONSIDER
THA
T
THIS
WILL
OCCUR
A NUMBER OF
TIMES EV
-
ER
Y DA
Y OF
THE COOLING SEASON
IT
IS EASY
T
O SEE
THA
T
THE DAMAGE
WILL
RAPIDL
Y
ACCUMULA
TE. IF
THE
PUMP
IS
ALLOWED OPERA
TE IN
THIS
CONDITION REPEA
TEDL
Y,
THE NOISY
PERIOD WILL
GET
LONGER
AND LON-
GER OVER
THE COOLING SEASON
UNTIL
THE CUST
OMER COMPLAINS
OR
THE PUMP
EVENTUALL
Y F
AILS.
THIS CAN EASIL
Y BE
AVOIDED BY
INST
ALLING
THE DISCHARGE HOSING
CORRECTL
Y WITH
AN
AIR GAP
WHICH
WILL
EQUALIZE
THE
ATMOSPHERIC
PRESSURE
AND ELIMINA
TE
THE
SIPHONING EFFECT
.
Incorrect
Fa
ilu
re
to
fo
llo
w
c
or
re
ct
Discharge Hose installation will damage pump
.
18
