Installation
900608-00 01/2019
Innovative Hearth Products
MHD40 Series Multi-View Direct-Vent Gas Fireplaces
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE
39
Burner Orifice Sizes (all models) *
Model
Natural
Gas
drill size (inches)
Propane
Gas
drill size (inches)
ST and PF
#32 (0.116")
37L82
1.65mm (0.065")
74L88
Table 9
Standard size installed at factory
Standard size if field converted
Part /Cat. Number
*For elevations of 0-4500 ft. or 0-1372 m
FRONT OF FIREPLACE
PAN BURNER
VENTURI TUBE ARM
AIR SHUTTER
ADJUSTMENT LEVER
FIREBOX SUBFLOOR
Figure 56
Millivolt Appliances
Step 4.
Refer to
Figure 57
and the instruc-
tions provided with the kit. Using a Torx T20,
remove and discard the three pressure regulator
mounting screws. Remove the pressure regu-
lator, spring, poppet, diaphragm and bushing.
Discard all removed components
. Ensure
the rubber gasket installed on the back of the
replacement pressure regulator is properly
positioned and install the new pressure regula-
tor using the new screws supplied with the kit.
Tighten screws to 25 In. lb. torque.
Pressure
Regulator
Remove
These
Components
Pilot
Orifice
All Models
Step 7
. (Refer to
Figure 59)
A.
Remove the orifice from the manifold and
replace it with the one provided in the kit.
The following Table shows the orifice sizes
for natural and propane models
. Figure 59
illustrates the orifice. Always check and verify
correct orifice size.
B.
Install the burner as shown in
Figure 60
.
Ensure that the arm of the venturi of the burner
is hooked onto the air shutter adjustment lever
(refer to
Figure 53 on Page 33).
The primary air
opening can be adjusted by rotating the adjust-
ment lever from beneath the firebox floor. Refer
to
Figure 53 on Page 33
for the recommended
minimum primary air opening setting.
Step 5.
Attach manometer to the manifold side
pressure test fitting and verify manifold pres-
sure reads 3.5 inches water column (0.87 kPa)
for natural gas, and 10.0 inches water column
(2.49 kPa) for propane gas.
Step 6.
Refer to
Figure 58
and remove the
pilot hood assembly to access the hexed pilot
orifice. Remove and replace the orifice with the
one provided with the kit.
Figure 57
Figure 58
Figure 59
Figure 60
Step 8.
Reassemble the remaining components
by reversing the procedures outlined in the
preceding steps.
Use pipe joint compound or Teflon tape on all
pipe fittings before installing (ensure propane
resistant compounds are used in propane ap-
plications, do not use pipe joint compounds
on flare fittings).
Step 9.
Attach the conversion label provided
in the conversion kit to the rating plate on the
appliance.
Step 10.
Turn on gas supply and test for gas
leaks.
ALWAYS TEST PRESSURE WITH THE VALVE
REGULATOR CONTROL AT THE HIGHEST
SETTING
BURNER POSITIONING
PAN
BURNER
PILOT ASSEMBLY
f i r e - p a r t s . c o m
