Natural Gas Models
  TK-Jr NG TK-2 NG TKD-20 NG TM-1 NG
Input BTU Rate 19,500 - 140,000 Btu 20,000 - 185,000 Btu 20,000 - 185,000 Btu 25,000 - 235,000 Btu
Thermal Efficiency 84% 85% 85% 82.3%
First Hour Rating (DOE) 180 Gal/Hr 240 Gal/Hr 240 Gal/Hr 300 Gal/Hr
Gas Connection 3/4" NPT 3/4" NPT 3/4" NPT 3/4" NPT
Water Connection 3/4" NPT 3/4" NPT 3/4" NPT 3/4" NPT
Water Pressure 15 - 150 PSI 15 - 150 PSI 15 - 150 PSI 15 - 150 PSI
Gas Pressure 5.0" - 10.5" WC 5.0" - 10.5" WC 5.0" - 10.5" WC 5.0" - 10.5" WC
Shipping Weight 30 lbs. 74 lbs. 70 lbs. 85 lbs.
Dimensions (HxWxD) 20" x 14" x 6" 24.5" x 16.5" x 8.3" 24" x 16.5" x 8" 24" x 18" x 9"
Exhaust Vent 4 in. 4 in. 4 in. 4 in.
Electrical Supply AC 120V, 0.8A AC 120V, 0.8A AC 120V, 0.8A AC 120 V, 0.8 A
Water Flow Rate 0.75 - 5.8 GPM 0.75 - 6.9 GPM 0.75 - 6.9 GPM 0.75 - 9.6 GPM
Flow Rate 50°in 120°out 3.2 GPM 4.5 GPM 4.7 GPM 5.9 GPM
Warranty 5 yr Limited 5 yr Limited 5 yr Limited 5 yr Limited
Price $749.00 $1450.00 $1470.00 $2497.00