19
7.3 COMBUSTION AIR FAN
TH uses a modulating air fan to provide combustible air/gas
mix to the burner and push the products of combustion
through the heat exchanger and venting system. The fan
assembly consists of a sealed housing and fan wheel
constructed from spark resistant cast aluminum. The fan is
operated by a fully enclosed 120 VAC, Single-Phase
EC/DC electric motor. The fan housing and motor assembly
is fully sealed and SHOULD NOT be field serviced. The
power draw of the motor is proportional to the modulated
gas input rate of the appliance.
7.4 GAS VALVE
Figure 19: Venturi and Gas Valve Arrangement
The Gas Valve supplied with the TH is a combined
valve/venturi assembly. A servo pressure regulator is
incorporated into the gas valve to provide stable gas
supply. Pressure taps are provided to check inlet and outlet
gas pressures. An internal fine mesh screen is incorporated
in the inlet of the gas valve to prevent debris from entering
the combustion chamber. Gas valves are factory set at low
and high fire and modulates to maintain combustion
characteristics across the full operating range.
7.5 OUTER JACKET
The outer jacket assembly is constructed from mirror finish
stainless steel. This ensures a long life for the jacket
assembly, with full integrity
