355CAV
NOTE: DO NOT set
!CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in reduced furnace life.
DO NOT bottom out gas valve regulator adjusting screws. This can result in unregulated manifold pressure and result in excess overfire and heat exchanger failures.
NOTE: If orifice hole appears damaged or it is suspected to have been redrilled, check orifice hole with a numbered drill bit of correct size. Never redrill an orifice. A
f. Move setup switch
g.Jumper R and W/W1 and W2 thermostat connections on furnace control. (See Fig. 33.) This keeps furnace locked in
h.Turn
NOTE: DO NOT set
i.Remove jumpers R to W/W1 and R to W2.
j.Wait for blower
k.Jumper R and W/W1 thermostat connections on control to start furnace.
l.Wait for the blower to turn ON then check
NOTE: DO NOT set
m. When correct manifold pressures are obtained, replace caps that conceal gas valve adjustment screws. Main burner flame should be clear blue, almost transparent. (See Fig. 62.)
n.Remove jumper across R and W/W1. If necessary move setup switch
3.Verify natural gas input rate by clocking gas meter.
NOTE: Be sure all pressure tubing,
a.Calculate
UNITED STATES
At altitudes above 2000 ft, this furnace has been approved for 2 percent derate for each 1000 ft above sea level. See Table 11 for derate multiplier factor and example.
CANADA
At installation altitudes from 2000 to 4500 ft, this furnace must be derated 5 percent by an authorized Gas Conversion Station or Dealer. To determine correct input rate for altitude, see example and use 0.95 as derate multiplier factor.
EXAMPLE: 80,000 BTUH
Furnace Input Rate at Sea Level X Derate Multiplier Factor = Furnace Input Rate at Installation Altitude 80,000 X 0.91 = 72,800
b.Reinstall burner box cover.
NOTE: Clocking gas input rate MUST always be performed with the burner box cover INSTALLED.
c. Check that gas valve adjustment caps are in place for proper input to be clocked.
d. Obtain average heat value (at altitude) from local gas supplier.
NOTE: Be sure heating value of gas used for calculations is correct for your altitude. Consult local gas utility for altitude adjustment of gas heating value.
e. Check and verify orifice size in furnace. NEVER ASSUME THE ORIFICE SIZE. ALWAYS CHECK AND VERIFY.
f.Turn off all other gas appliances and pilots.
g.Move setup switch
BURNER
ORIFICE
A93059
Fig. 61 - Burner Orifice
54