Gas Pressure - Superior Fireplaces MHD 35 Series Installation And Operation Instructions Manual

Innovative Hearth Products
MHD 35/40 Series Direct-Vent Gas Fireplaces
BTU Input
Table 1 - Input Rate (BTU/HR), Gas Valves
Table 2 - Thermal Efficiency (%)
* AFUE is a measurement of the US Department of Energy, ** P4 (EnerGuide) is a measurement of the Canadian Office of Energy Efficiency.
Efficiencies are based on Normal input operation.

Gas Pressure

Table 3 - Inlet Gas Supply Pressure
Table 4 - Manifold Gas Supply Pressure
Test gauge connections are provided on the front of the millivolt gas control valve (identified IN for the inlet and OUT for
the manifold side). The control valves have a 3/8" (10 mm) NPT thread inlet and outlet side of the valve (Figure 1).
Figure 1 - Millivolt Gas Valve
Propane tanks are at pressures that will cause damage to valve components. Verify that the tanks have step down
regulators to reduce the pressure to safe levels.
The appliance and its appliance main gas valve must be disconnected from the gas supply piping system during
any pressure testing of that system at test pressures in excess of 1/2 psi (3.5 kPa).
The appliance must be isolated from the gas supply piping system by closing its equipment shutoff valve during
any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 psi (3.5 kPa).
Models
35" Models
40" Models
Model
AFUE *
35" Models
40" Models
Fuel
Natural Gas
Propane
Fuel
Natural Gas
Propane
Natural Gas
High Rate Low Rate
16,000 11,000
20,000 14,000
Millivolt
P4 **
66 61
66 61
Minimum
5" WC / (1.25 kPa)
11.0" WC / (2.74 kPa)
General Information
900414-00 12/2015
Propane Gas
High Rate Low Rate
15,000 11,000
19,000 14,000
Electronic
AFUE * P4 **
66 63
66 63
Maximum
10.5" WC / (2.61 kPa)
13.0" WC / (3.23 kPa)
Pressure
3.5" WC / (0.87 kPa)
10.0" WC / (2.49 kPa)
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