Start-up. adjustment and safety check, Sequence of operation – Carrier 58GS User Manual
Page 8
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BOTTOM CLOSURE PANEL — When the side
inlet is used, the bottom opening must be properly
sealed by installing a bottom closure panel shipped
under the filter in each furnace. To install the
bottom closure panel, perform the following steps:
1
.
After filter has been installed for side return, re
move bottom closure panel from furnace.
With furnace either tilted or raised, install panel
in opening on bottom of furnace, making certain
that locating tabs rest securely against sides
of cabinet. See Fig. 9.
WARNING: Never operate unit without a iiiter
or with filler acce.ss door removed-
eorroM
aosu!^ PANEL
LOCATING TASS
Fig. 9 — Installing Bottom Closure Panel
START-UP. ADJUSTMENT AND
SAFETY CHECK
Sequence of Operation
HEATING — Sizes 050 thru 150 (BDP 646AW gas
valve)
TIME (sec)*
ACTION
0
35
“”45'’
11b
20
75
Thermostat calls for heat. The control circuit be
tween R and W is closed: power from transformer
simultaneously opens solenoid of pilot gas valve
(inside main gas valve) and energizes spark
igniter
PiTot^as ignites
TTlof coritacTslnbffnaTly closed) open.'Spark
igniter ceases to spark
Pilot contacts (normally open) close, energizing
heat motor in main gas valve and solid-state
timing circuit in printed circuit control centejr^______
Heat motor opens main gas valve; main Burners
ignite from pilot flame
SoHd^itife tirning'cnxuiUswitches iti contacts
and blower motor starts
Thermostat is satisfied. Circuit between R and W
is broken; automatic gas valve is de-energized,
closing solenoid valve Solid-state timing circuit
is de-energized
T^in gas "valvelmd pilot valve close, extinguishing
flame
Piiot safety contacts open.
PIloTcontacts cioseTready for new cycle Solid-
state timing circuit switches its contacts, stopping
blower motor
‘Times are approximate: variance ±20%
HEATING — Size 175 (Essex 242 gas valve)
TIME (sec)*
0
75
1
75
ACTION
Thermostat calls for heat, power from transformer
simultaneously opens solenoid of pilot gas valve
(inside main gas valve) and energizes spark
igniter Solid-state timing circuit is energized
Pilot gas ignites
Once pilot flame is proven electrically, igniter
ceases to spark, main gas valve opens and mam
burners ignite from pilot flame
Solid-state timing circuit switches its confacfs
and blower motor starts
Thermostat is satisfied Pilot and main gas valves
are de-energized Solid-state timing circuit is
de-energized
_
_
Pilot and main burners are extingmsh^_ ____________
Solid-state timing circuit switches its contacts,
stopping blower motor
‘Times are approximate, variance ±20%
LIMIT SWITCH — If the furnace overheats for
any reason, the limit switch will open, breaking the
circuit to automatic gas valve, so the gas valve
closes immediately. Without low-voltage current
applied to heat relay, its normally closed contacts
energize blower motor.