| 2400-322 | Gasket Kit | | |
| 2400-079 | Blower Assembly (#5) | | |
| 2400-086 | Combustion Coil Assembly (#9) | | |
| 2400-082 | Flame Holder (#7) | | |
| 2400-308 | Flame Holder (HWG-250) | | |
| 2400-286 | Ignitor | | |
| 2400-088 | Capacitor, Motor Starter | | |
| 2400-224 | Control Board | | |
| 2400-014 | Gas Valve, Neg. Pres. (#6) | | |
| 2400-015 | Gas Valve, Neg. Pres. (HWG-250) | | |
| 2400-106 | Pressure Diff. Switch (HWG-250) | | |
| 2400-058 | Intake / Exhaust TCO | | |
| 2400-057 | Operating Limit | | |
| 2400-054 | Safety Limit | | |
| 2400-062 | Time Dealy Relay | | |
| 2400-130 | | | |
| 2400-006 | Transformer | | |
| 2400-094 | Pressure Relief Valve (150 psi) | | |
| 2400-095 | P.R. Valve (250 only) (150 psi) | | |
| 2400-090 | Pump, Grundfos Up 26-99BF (#2) | | |
| 2400-104 | Exhaust Terminal | | |
| 2400-102 | Intake Terminal | | |
| 2400-100 | Wall Flange | | |
