General Information
900960-00C, 06/2019
Innovative Hearth Products
DRT3500-C Series Direct-Vent Gas Fireplaces
9
BTU Input
Table 1 - Input Rate (BTU/HR), Gas Valves
Models
Natural Gas
Propane Gas
High Rate
Low Rate
High Rate
Low Rate
35” Models
26,000
17,000
23,000
18,000
40” Models
33,000
23,000
27,000
20,000
45” Models
35,000
24,000
30,000
23,000
Table 2 - Thermal Efficiency (%)
Gas Pressure
Table 3 - Inlet Line Gas Pressures
Fuel
Minimum
Maximum
Natural Gas
5” WC / (1.25 kPa)
10.5” WC / (2.61 kPa)
Propane
11.0” WC / (2.74 kPa)
13.0” WC / (3.23 kPa)
Table 4 - Manifold Outlet Gas Supply Pressure
Fuel
Pressure
Natural Gas
3.5” WC / (0.87 kPa)
Propane
10.0” WC / (2.49 kPa)
Test gauge connections are provided on the front of the electronic 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
).
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.
Figure 1 - MANIFOLD Outlet Gas Pressure Test Point
Model
Electronic
AFUE *
P4 **
Natural
Propane
Natural
Propane
35” Models
68.5
67
62.5
69.6
40” Models
68.1
66
62.4
62.6
45” Models
67.2
64
62.9
63
* AFUE is a measurement of the US Department of Energy,
** Complies with CSA P.4.1-2015 “Testing Method for Measuring Annual Fireplace Efficiency. P4 (EnerGuide) is a measurement of the
Canadian Office of Energy Efficiency.
Efficiencies are based on Normal input operation.
Based on CSA P.4.1-2015
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).
Orange Wire
(from DFC Wire
Harness)
Pressure Regulator
Tower
Main Gas Inlet
3/8" NPT
Green Wire
(from DFC Wire Harness)
Inlet (IN) Test Port
Manifold (OUT)
Test Port
Connect GTMS
wire harness
Yellow Ground Wire
(from DFC Wire Harness)
Side View
