Carrier 48VL-E Installation Instructions Manual page 14

48VL-(E, F): Installation Instructions
Fig. 11 – Burner Assembly
Manifold
Pressure Port
Fig. 12 – BurnerBox/Gas Manifold Assembly
Check Heating Control
Start and check the unit for proper heating control operation as follows
(see furnace lighting instructions located on the inside of the control
access panel):
1. Place room thermostat SYSTEM switch in the HEAT position and
the fan switch is placed in AUTO position.
2. Set the heating temperature control of the thermostat above room
temperature.
3. The induced-draft motor will start.
4. On a call for heating, the main burner should light within 5 sec. of
the spark being energized. If the burners do not light, there is a
22-sec. delay before another 5-sec. try. If the burners still do not
light, this sequence is repeated. If the burners do not light on the 4th
ignition attempt, there is a lockout. To reset the control, break the
24-v power to W.
5. The evaporator fan will turn on 30 sec. after the flame has been
established. The evaporator fan will turn off 90 sec. after the
thermostat has been satisfied. Please note that the integrated gas
unit controller (IGC) has the capability to automatically reduce the
evaporator "ON" delay and increase the evaporator "OFF" delay in
the event of high duct static and/or partially-clogged filter.
Check Gas Input
Check gas input and manifold pressure after unit start-up (See
If adjustment is required proceed as follows:
• The rated gas inputs shown in
to 2000 ft (610 m) above sea level. These inputs are based on natural
gas with a heating value of 1025 Btu/ft
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Table
Table 5 are for altitudes from sea level
3
at 0.60 specific gravity.
Table 3 – Altitude Derate Multiplier for U.S.A.
†
Altitude ft (m)
0-2000
(0-610)
*. In Canada see Canadian Altitude Adjustment.
†. Altitude of 2001 ft and above is not allowed.
‡. Derate multiplier factors are based on midpoint altitude for altitude range.
When the gas supply being used has a different heating value or specific
gravity, refer to national and local codes, or contact your distributor to
determine the required orifice size.
UNIT DAMAGE HAZARD
A180078
Failure to follow this caution may result in reduced unit and/or
component life.
Do Not redrill an orifice. Improper drilling (burrs, out-of-round holes,
etc.) can cause excessive burner noise and misdirection of burner flame.
If orifice hole appears damaged or it is suspected to have been redrilled,
check orifice hole with a numbered drill bit of correct size.
Adjust Gas Input
The gas input to the unit is determined by measuring the gas flow at the
meter or by measuring the manifold pressure. Measuring the gas flow at
the meter is recommended for natural gas units. Measure Gas Flow
(Natural Gas Units)
Minor adjustment to the gas flow can be made by changing the manifold
pressure. The manifold pressure must be maintained between 3.2 and 3.8
IN. W.C.
A200293
ON/OFF SWITCH
INLET
PRESSURE TAP
Fig. 13 – Single-Stage Gas Valve
If larger adjustments are required, change main burner orifices following
the recommendations of national and local codes.
NOTE: All other appliances that use the same meter must be turned off
when gas flow is measured at the meter.
5).
Proceed as follows:
1. Turn off gas supply to unit.
2. For ultra low NOx models remove manifold pressure tap cover
using an allen wrench. (See
hose to connect to manometer. Turn on gas supply to unit.
3. Record number of seconds for gas meter test dial to make one
revolution.
14
Derate Multiplier
Percent of Derate
0
WARNING
!
REGULATOR
COVER SCREW
PLASTIC
ADJUSTMENT
SCREW
REGULATOR SPRING
(PROPANE - WHITE)
(
NATURAL - SILVER)
GAS PRESSURE
REGULATOR
ADJUSTMENT
MANIFOLD
PRESSURE TAP
Fig. 13). Install barbed pressure tap and
*
‡
Factor
1.00
A07751