Tempstar F8MTL, Руководство по установке

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441 01 2101 05
Specifications are subject to change without notice.
c. Connect a water column manometer or similar device
to manifold pressure tap.
d. Turn gas valve ON/OFF switch to ON.
Figure 48 − Redundant Automatic Gas Control Valve
A06667
e. Move setup switch TT (SW1 − 1) on furnace control to
ON position to lock furnace in low − heat operation.
(See Figure 33 and Table 10)
f. Manually close blower door switch.
g. Jumper R and W/W1 thermostat connections on
control to start furnace. (See Figure 33)
h. Remove regulator adjustment cap from low − heat gas
valve pressure regulators. (See Figure 48) Turn
low − heat adjusting screw (3/16 in. (5 mm) or smaller
flat tipped screwdriver) counterclockwise (out) to
decrease input rate or clockwise (in) to increase input
rate.
NOTE : DO NOT set low − heat manifold pressure less than
1.4 − In. W.C. or more than 1.7 − In. W.C. for natural gas. If
manifold pressure is outside this range, change main burner
orifices.
i. Install low − heat regulator adjustment cap.
j. Leave manometer or similar device connected and
proceed to Step 4.
NOTE : If orifice hole appears damaged or it is suspected to
have been re − drilled, check orifice hole with a numbered drill
bit of correct size. Never re − drill an orifice. A burr − free and
squarely aligned orifice hole is essential for proper flame
characteristics.
4. Verify natural gas low − heat input rate by clocking
meter.
NOTE : Gas valve regulator adjustment caps must be in
place for proper input to be clocked.
a. Turn off all other gas appliances and pilots served by
the meter.
b. Run for 3 minutes in low − heat operation.
c. Measure time (in sec) 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.
Figure 49 − Orifice Hole
BURNER
ORIFICE
A93059
d. Refer to Table 12 for cubic ft. of gas per hr.
e. 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 manifold pressure
to increase input or decrease manifold pressure to
decrease input. Repeat steps b through e until correct
low heat input is achieved. Re − install low − heat
regulator seal cap on gas valve.
5. Set low − heat temperature rise. The furnace must
operate within the temperature rise ranges specified on
the furnace rating plate. Do not exceed temperature
rise ranges specified on unit rating plate for high − and
low − heat. 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.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Disconnect 115
− v electrical power before changing
speed tap.
!
WARNING
a. Verify unit is running in low heat per Step 3. 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 low heat operation.
(2.) Derate for altitude if applicable.
(3.) Return and supply ducts for excessive
restrictions causing static pressures greater than
0.50 − In. W.C.