Carrier 59SU5A Manual page 46

59SU5A: Installation, Start-up, Operating and Service Maintenance Instructions
5. Verify natural gas input rate by clocking meter.
NOTE: Gas valve regulator adjustment cap must be in place for proper
input to be clocked.
a. Turn off all other gas appliances and pilots served by the meter.
b. Jumper R and W thermostat connections at the furnace control
board.
c. Run furnace for 15 minutes in heating operation.
d. Measure time (in seconds) for gas meter to complete 1 revolution
and note reading. The 2 or 5 cubic feet dial provides a more
accurate measurement of gas flow.
e. For cubic ft. of gas per hr
f. Multiply gas rate (cu ft./hr) by heating value (BTUh/cu ft.) to
obtain input.
If clocked rate does not match required input from Step 1, increase gas
valve outlet pressure to increase input or decrease gas valve outlet
pressure to decrease input. Repeat steps b through e until correct input is
achieved. Reinstall regulator seal cap on gas valve.
6. Restore furnace to normal operating condition.
a. When correct input rate and temperature rise is achieved, turn
gas valve ON/OFF switch to OFF.
b. Remove manometer or similar device from gas valve.
c. Tighten set screw on outlet tower
wrench.
d. Turn gas valve ON/OFF switch to ON.
e. Check for gas leaks and verify furnace operation.
7. Set temperature rise. The furnace must operate within the
temperature rise ranges specified on the furnace rating plate.
Determine the temperature rise as follows:
NOTE: Blower access door must be installed when taking temperature
rise reading. Leaving blower access door off will result in incorrect
temperature measurements.
CAUTION
!
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in:
- Overheating the heat exchangers or condensing flue gases in
heat exchanger areas not designed for condensate.
- Shortened furnace life
- Component damage
Temperature rise must be within limits specified on furnace rating plate.
Recommended operation is at midpoint of rise range or slightly above.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Disconnect 115-v electrical power and install lockout tag before
changing speed tap.
a. Place thermometers in return and supply ducts as close to furnace
as possible. Be sure thermometers do not see radiant heat from
heat exchangers. Radiant heat affects temperature rise readings.
This practice is particularly important with straight-run ducts.
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine air
temperature rise.
NOTE: If the temperature rise is outside this range, first check:
(1.) Gas input for heating operation.
(2.) Return and supply ducts for excessive restrictions causing
static pressures greater than the maximum heating static
listed on the rating plate.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
(Table 21).
pressure tap with 3/32 in. hex
c. Adjust air temperature rise by adjusting blower speed. Increase
blower speed to reduce temperature rise. Decrease blower speed
to increase temperature rise
d. Turn thermostat down below room temperature and remove
blower access door.
e. To change motor speed selection for heating, remove blower
motor lead from control HEAT terminal - Wiring Diagram (see
Fig. 68) Select desired blower motor speed lead from one of the
other terminals and relocate it to the HEAT terminal - lead color
identification (Table
terminal.
f. Repeat steps a through e.
8. Set thermostat heat anticipator.
a. Mechanical thermostat - Set thermostat heat anticipator to match
the amp. draw of the electrical components in the R-W circuit.
Accurate amp. draw readings can be obtained at the wires
normally connected to thermostat subbase terminals, R and W.
The thermostat anticipator should NOT be in the circuit while
measuring current.
Fig. 61 – Orifice Hole
!
FIRE HAZARD
Failure to follow this warning could result in personal injury, death,
and/or property damage.
Gas valve outlet pressure tap must be tightened to prevent gas leak.
!
FURNACE OVERHEATING HAZARD
Failure to follow this caution may result in reduced furnace life.
Recheck temperature rise. It must be within limits specified on the
rating plate. Recommended operation is at the mid-point of rise range
or slightly above.
(1.) Remove thermostat from subbase or from wall.
(2.) Connect an amp. meter (see
subbase terminals or R and W wires at wall.
(3.) Record amp. draw across terminals when furnace is in
heating and after blower starts.
(4.) Set heat anticipator on thermostat per thermostat
instructions and install on subbase or wall.
46
11). Reconnect original lead to SPARE
BURNER
ORIFICE
WARNING
CAUTION
Fig. 62) across the R and W
A180238