General Information
900683-01F, 10/2018
Innovative Hearth Products
DRT3500 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
20,000
14,000
19,000
13,000
40” Models
24,000
17,000
22,000
17,000
45” Models
28,000
18,500
26,000
20,000
Table 2 - Thermal Efficiency (%)
Model
Electronic
AFUE *
P4 **
35” Models
66
64
40” Models
66
64
45” Models
67
65
Gas Pressure
Table 3 - Inlet Gas Supply Pressure
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 Gas Supply Pressure
Fuel
Pressure
Natural Gas
3.5” WC / (0.87 kPa)
Propane
10.0” WC / (2.49 kPa)
The high and low manifold test gauge connections are provided on the stem of the electronic gas valve (see Figure 1A).
The inlet line gas pressure test point is shown in Figure 1B. The control valves have a 3/8” (10 mm) NPT thread
inlet and outlet side of the 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.
Some parts have been removed for clarity
1/8” Inlet line gas pressure ‘test point’ plug (in control compartment)
Testing Inlet Line Gas Pressure (Qualified Technicians
Only):
1. Turn off gas shutoff valve and electrical.
2. Remove 1/8” plug (shown in diagram to the right).
3. Install an 1/8” nipple in place of plug.
4. Connect manometer to nipple, using an 1/8” NPT air
hose nipple/fitting.
5. Turn on shutoff valve and check for proper inlet gas
pressure.
6. Reverse steps 1-5.
Figure 1B - INLET Line Gas Pressure Test Point
Figure 1 - MANIFOLD Outlet Gas Pressure Test Point
Figure 1A
Outlet Pressure
Test Point
Inlet Pressure
Test Point
Ecoflow
* 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
