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SPECIFICATIONS GAS HEAT
Model No. 036, 048 
060, 074
036, 048 
060, 074
048 
060, 074
Heat Input Type Standard (2 Stage) Medium (2 Stage) High (2 Stage)
Input 
Btuh
1st Stage  81,000 113,000
2nd Stage  108,000 
Output 
Btuh
1st Stage 43,000 66,000 92,000
2nd Stage  87,000 121,000
Temperature 
1st stage   30 - 60
2nd Stage  30 - 70 
1 
 81% 81% 81%
Gas Supply Connections 1/2 in. NPT
Recommended Gas Supply Pressure - Nat. / LPG 7 in. w.g. / 11 in. w.g.
Gas Supply Pressure 
Range
 
Min./Max. (LPG) 
1
HIGH ALTITUDE DERATE 
NOTE - Units may be installed at altitudes 
up to 2000 ft. above sea level without any 
units must be derated to match information 
ft. unit must be derated 2% for each 1000 ft. 
above sea level. 
NOTE - This is the only permissible derate 
for these units.
Heat Input Type  Altitude Feet 
Gas Manifold Pressure 
in. w.g. 
Input Rate (Btuh) 
Natural Gas  LPG/Propane 
Standard (2 stage)  3.0/1.7  60,000 / 49,000
Medium (2 stage)  3.0/1.7   
High (2 stage)   3.0/1.7   139,000 / 104,000