158715 ⎘
Details; Combustion air preheating by double wall boiler mantle
COMBUSTION CHAMBER AND GAS APPARATUS
#2Water heater sealed combustion chamber assembly
#3COMBUSTION SYSTEM
#4Gas water heater having carbon dioxide detector
#5Gas water heater having nitric oxide detector
#6Heat exchanger and water heater
#7Instantaneous fuel-fired water heater with low temperature plastic vent structure