Carrier 58BB - Manual (Page 10)

Input Adjustment
1. Turn off all other gas appliances on same meter.
2. Set thermostat high enough to ignite burners.
3. Check cu ft of gas burned per minute. Multiply
value by 60 minutes to determine input (in
thousands of Btuh). Rating should be within
5% of nameplate input rating.
4. To adjust input, remove combination gas valve
cap covering regulator adjusting screw. (See
Fig. 7.)
5. With a small screwdriver, rotate adjustment
screw clockwise to increase or counterclockwise
to decrease pressure. Do not change pressure
more than ± 0.3 in. wg.
6. Replace regulator adjustment screw cap.
IMPORTANT; Refer to operating and main-
tenance instruction Eterature to ensure better,
longer, and more reEable service from your new
Carrier furnace.
TROUBLESHOOTING
Burner Will Not Operate
POWER FAILURE — Power switch off — set to
on, blown fuse — replace, defective wiring —
replace
NO POWER TO CONTROLS - Thermostat set too
low, dirty or defective — reset, clean or replace as
applicable; defective transformer — replace; faulty
limit switch — replace; blown fusestat ~ replace
BURNER WILL NOT IGNITE ^ Low gas pressure
or no gas to unit — check if manual shutoff valve is
closed, check gas supply, check for clogged gas line
and clean or repair, adjust gas pressure with all
appliances operating; faulty thermocouple — check
with millivoltmeter and replace if necessary; pilot
light extinguished — locate cause and relight, dirty
pilot — clean
Burner Operates, But Heating Inadequate
UNIT UNDERSIZED — Size selected incorrectly —
never overfire, replace with properly sized unit
FUEL INPUT TOO LOW — Wrong orifice size —
replace orifice; regulator set too low — readjust.
THERMOSTAT OPENS TOO SOON - Wrong
anticipator setting ~ readjust; thermostat out of
cahbration — recalibrate; thermostat set wrong —
check and reset as necessary; wrong thermostat
location — relocate.
LIMIT SWITCH CYCLES BURNER - Dirty filters
-- clean or replace, faulty fan switch or motor —
repair or replace; blower speed too low — readjust;
fan switch set too high — readjust; duct system
restricted — remove restriction.
Poor Combustion and Flame Characteristics
SMOKY FLAME — Insufficient air — adjust air
inlet; flue restriction — remove restriction; down-
draft — eliminate downdraft using flue caps on
vents
NOISY BURNER — Too much air — adjust air
inlet, incorrect input — make correction as
required
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