93
Should overheating occur with a gas heat
exchanger, or the gas supply fail to shut off,
shut off the manual gas valve to the furnace
before shutting off the electrical supply.
Prolonged overheating of the heat exchanger
will shorten its life.
If unit has not been selected as a 100%
outside air unit (makeup air unit) the return
air duct must be sealed to the unit and the
return air temperature must be maintained
between 55F and 80F.
Table 27 - Electric and Gas Heating Capacities