Unvented Gas Log Heater/ Vented Decorative
Appliance Installation and Operating Instructions
Models: PH18 (for use with PH18R Log Sets)
PH24 (for use with PH24R or PH30R Log Sets)
WARNINGS
If the information in this manual is not
followed exactly, a re or explosion may
result causing property damage, personal
injury or loss of life.
– Do not store or use gasoline or other
ammable vapors and liquids in the
vicinity of this or any other appliance.
– WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do
not use any phone in your building.
• Immediately call your gas supplier
from a neighbor's phone. Follow the
gas supplier's instructions.
• If you cannot reach your gas supplier,
call the re department.
– Installation and service must be per-
formed by a qualied installer, service
agency or the gas supplier.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
This is an unvented gas-red heater. It uses air
(oxygen) from the room in which it is installed.
Provisions for adequate combustion and ventilation
air must be provided. Refer to page 8.
INSTALLER: Leave this manual with the appliance.
CONSUMER: Retain this manual for
future reference.
PH Gas Logs
Thank you and congratulations on your purchase of an Monessen Log Set.
PLEASE READ THE INSTALLATION AND OPERATION INSTRUCTIONS BEFORE USING THE APPLIANCE!
IMPORTANT: Read all instructions and warnings carefully before starting installation.
Failure to follow these instructions may result in a possible re hazard and will void the warranty.
CONTENTS
Carbon Monoxide Warning ........................................ 2
Important Safety Information .................................... 3
Codes ..................................................................... 4
Product Features ........................................................ 5
Gas Specications ................................................. 5
Gas Pressures ....................................................... 5
Ignition Controls ..................................................... 5
Pilot/ODS ............................................................... 5
Thermal Generator ................................................. 5
Getting Started ............................................................ 6
Fireplace and Hearth Dimensions............................. 7
Placement in a Fireplace with Restrictive Barrier ... 7
►
Adequate Combustion Ventilation Air ...................... 8
Clearances and Height Requirements ...................... 9
Installation Requirements........................................ 10
Installation ................................................................. 12
Installing Vented Applications .............................. 12
Damper Stop Installation ...................................... 12
Place and Secure Appliance ................................ 12
Assembly Procedure ............................................ 13
Gas Line Connection ................................................ 13
Check Gas Pressure................................................. 14
Manual Control ..................................................... 14
Millivolt Control ..................................................... 14
Electrical Wiring - Millivolt ....................................... 15
Optional Wall Switch or Thermostat ..................... 15
Optional Remote Receiver ................................... 16
Check System Operation ..................................... 16
Log Placement .......................................................... 17
PH18-R ................................................................ 17
PH24-R ................................................................ 19
PH30-R ................................................................ 21
Flame Appearance .................................................... 23
Millivolt Control ..................................................... 23
Manual Control ..................................................... 23
Burner Flame ....................................................... 24
Operating Instructions ............................................. 25
For Your Safety Read Before Lighting ................. 26
Manual Control Lighting Instructions .................... 27
Millivolt Control Lighting Instructions .................... 28
Match Lighting Instructions .................................. 29
Cleaning and Servicing ............................................ 29
Troubleshooting ....................................................... 30
Service Parts ............................................................. 32
Accessories .......................................................... 38
►
Massachusetts Residents Only............................... 39
Warranty .................................................................... 40
NOTE: Monessen vent ree gas logs are hand painted for
ultimate beauty and realism. As a result, some variation
in color and shading will occur from set to set. This is
intentional and designed to make each product unique,
as found in nature.
CARBON MONOXIDE POISONING: Early signs of carbon monoxide poisoning are similar to the u with
headaches, dizziness and/or nausea. If you have these signs, the insert may not have been installed
properly. Get fresh air at once! Have the insert inspected and serviced by a qualied service person. Some
people are more affected by carbon monoxide than others. These include pregnant women, people with
heart or lung disease or anemia, those under the inuence of alcohol, and those at high altitudes.
Propane/LP gas and natural gas are both odorless. An odor-making agent is added to each of these gases.
The odor helps you detect a gas leak. However, the odor added to these gases can fade. Gas may be
present even though no odor exists.
2
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
IMPORTANT SAFETY INFORMATION
PH Gas Logs
INSTALLER
Please leave these instructions with the appliance.
OWNER
Please retain these instructions for future reference
• Any change to this heater or its controls can be dangerous.
• Improper installation or use of the heater can cause serious injury or death from re, burns,
explosion or carbon monoxide poisoning.
• Do not allow fans to blow directly into the replace. Avoid any drafts that alter burner ame
patterns.
WARNING
• Do not use a blower insert, heat exchanger insert or other accessory, not approved for use
with this heater where applicable.
1. Due to high temperatures, the appliance should be
located out of trafc and away from furniture and
draperies.
2. Children and adults should be alerted to the hazard
of high surface temperature and should stay away to
avoid burns or clothing ignition.
3. Young children should be carefully supervised when
they are in the same room with the appliance.
4. Do not place clothing or other ammable material on
or near the appliance.
5. Any safety screen or guard removed for servicing an
appliance, must be replaced prior to operating the
heater.
6. Installation and repair should be done by a qualied
service person.
7. To prevent malfunction and/or sooting, an unvented
gas heater should be cleaned before use and at least
annually by a professional service person. More frequent cleaning may be required due to excessive lint
from carpeting, bedding materials, etc. It is imperative
that control compartments, burners and circulating air
passageways be kept clean.
8. For propane/LP insert, do not place propane/LP supply
tank(s) inside any structure. Locate propane/LP supply
tank(s) outdoors. To prevent performance problems,
do not use propane/LP fuel tank of less than 100
lbs. capacity.
9. The installation must conform with local codes or, in the
absence of local codes, with the National Fuel Gas
Code, ANSI Z223.l/NFPA54.
10. This unit complies with ANSI Z21.11 Unvented Heat-
ers, latest edition and also complies with ANSI Z21.60
Decorative Vented Appliances for Solid Fuel Burning
Fireplaces, latest edition. State and local codes may
only allow operation of this appliance in a vented
conguration. Check your state or local codes. For
vented operation, refer to Vented Instructions in this
manual.
11. Do not install the heaters in a bathroom or bedroom.
12. Correct installation of the ceramic ber logs, proper
location of the heater, and annual cleaning are neces-
sary to avoid potential problems with sooting. Sooting,
resulting from improper installation or operation, can
settle on surfaces outside the replace. See log placement instructions for proper installation.
13. Avoid any drafts that alter burner ame patterns. Do not
allow fans to blow directly into replace. Do not place
a blower inside burn area of rebox. Ceiling fans may
create drafts that alter burner ame patterns. Sooting
and improper burning will occur.
14. CAUTION: Candles, incense, oil lamps, etc. produce
combustion by-products including soot. Vent-free
appliances will not lter or clean soot produced by
these types of products. In addition, the smoke and/or
aromatics (scents) may be reburnt in the vent-free ap-
pliance which can produce odors. It is recommended
to minimize the use of candles, incense, etc. while the
vent-free appliance is in operation.
15. This is an unvented gas-red heater. It uses air (oxygen) from the room in which it is installed. Provisions
for adequate combustion and ventilation air must be
provided. Refer to Page 6.
16. This heater shall not be installed in a room or space
unless the required volume of indoor combustion air is
provided by the method described in the National Fuel
Gas Code, ANSI Z223.1/NFPA 54, the International
Fuel Gas Code or applicable local codes.
17. Keep room area clear and free from combustible
materials, gasoline and other ammable vapors and
liquids.
18. Unvented gas heaters are a supplemental zone heater.
They are not intended to be a primary heating appli-
ance. Water vapor produced by an unvented heater
can create moisture problems in a home when oper-
ated for extended periods of time.
19. During manufacturing, fabricating and shipping, various
components of this appliance are treated with certain
oils, lms or bonding agents. These chemicals are not
harmful but may produce annoying smoke and smells
.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
3
PH Gas Logs
as they are burned off during the initial operation of the
appliance; possibly causing headaches or eye or lung
irritation. This is a normal and temporary occurrence.
The initial break-in operation should last two to three
hours with the burner at the highest setting. Provide
maximum ventilation by opening windows or doors to
allow odors to dissipate. Any odors remaining after this
initial break-in period will be slight and will disappear
with continued use.
20. Input ratings are shown in BTU per hour and are for
elevations up to 2,000 feet. For elevations above 2,000
feet, input ratings should be reduced 4 percent for each
1,000 feet above sea level. See the National Fuel Gas
Code.
21. The heater and its individual shutoff 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 psig (3.5 kPa).
22. The heater must be isolated from the gas supply piping
system by closing its individual manual shutoff valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 psig
(3.5 kPa).
23. Do not use this room heater if any part has been under
water. Immediately call a qualied service technician
to inspect the room heater and to replace any part
of the control system and any gas control which has
been under water.
24. This appliance must not be used with glass doors in
the closed position. This can lead to pilot outages and
severe sooting outside the replace.
25. Never burn solid fuels in a replace where an unvented
room heater is installed.
26. Always have a replace screen in place when the ap-
pliance is in operation and , unless other provisions for
combustion air are provided, the screen shall have an
opening(s) for induction of combustion air.
Attention Massachusetts Residents:
This product must be installed by a licensed gas
tter.
IMPORTANT SAFETY INFORMATION
Never connect unit to private (non-utility)
gas wells. This gas is commonly known
as wellhead gas.
WARNING
This appliance may be installed in an aftermarket,
permanently located, manufactured (mobile) home,
where not prohibited by local codes.
This appliance is only for use with the type of gas
indicated on the rating plate. This appliance is not
convertible for use with other gases.
CODES
Adhere to all local codes or, in their absence, the latest
edition of THE NATIONAL FUEL GAS CODE ANSI Z223.1
or NFPA54 which can be obtained from…
American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018
or
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
WARNING: This product and the
fuels used to operate this product (liquid
propane or natural gas), and the products
of combustion of such fuels, can expose
you to chemicals including benzene, which
is known to the State of California to cause
cancer and reproductive harm. For more
information go to: www.P65Warnings.
ca.gov.
4
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
PRODUCT FEATURES
PH Gas Logs
GAS SPECIFICATIONS
Min.Input Max. Input
Model Fuel Control BTU/h BTU/h
PH18NM Nat. Manual 18,000 30,000
PH18NV Nat. Millivolt 26,000 30,000
PH24NM Nat. Manual 19,000 36,000
PH24NV Nat. Millivolt 24,000 36,000
PH18PM LP Manual 22,500 30,000
PH18PV LP Millivolt 24,500 30,000
PH24PM LP Manual 25,000 36,000
PH24PV LP Millivolt 29,000 36,000
GAS PRESSURES
Natural Propane (LP)
Manual Regulator Pressure 4.0" w.c. 10.0" w.c.
Millivolt Regulator Pressure 3.5" w.c. 10.0" w.c.
Millivolt Pilot Regulator 3.5" w.c. n/a
Max. Gas Inlet Pressure 10.5" w.c. 13.0" w.c.
Min. Gas Inlet Pressure 5.0" w.c. 11.0" w.c.
NOTE: An external regulator is required to reduce supply
pressure to a maximum of 13.0" w.c. for LP systems.
IGNITION CONTROLS
Piezo ignitor allows ignition of the pilot without the
use of matches or batteries.
Manual control has three (3) positions:
OFF - All gas to the gas logs is shut off at
the valve.
IGN - Valve position to light/maintain a
standing pilot.
HI/LOW - Variable position corresponding to
desired ame height.
Millivolt control has four (4) positions:
OFF - All gas to the gas logs is shut off at
the valve.
IGN - Valve position to light/maintain a
standing pilot.
ON - Valve position to turn ON/OFF log
set with remote switch/thermostat.
HI/LO - Variable position to control ame
height (heat output).
PILOT/ODS
The gas log heater is tted with a specially designed
safety pilot (ODS assembly) which senses the amount
of oxygen available in the room and shuts the gas log
heater off if the oxygen level begins to drop below
a satisfactory level. The pilot can only be relit when
adequate fresh air is available.
THERMAL GENERATOR
The millivolt gas log pilot is tted with a millivolt
(thermopile) generator to provide power for remote
activation.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
5
PH Gas Logs
GETTING STARTED
• Handle the gas log burner assembly by
the burner only. Do not pick the unit up
by the burners or grate (not attached to
frame).
• Gloves are recommended when handling
ceramic ber logs to prevent skin irritation
CAUTION
from loose fibers. Logs are fragile —
handle with care.
MAKE SURE YOU HAVE RECEIVED ALL PARTS:
Check your packing list to verify that all listed parts have
been received. You should have the following:
• Unvented gas log burner assembly
• Plastic bag containing crushed volcanic rock
• Installation/operating instructions
• Two (2) anchoring screws
• Grate
• Ceramic ber or refractory cement logs
The millivolt controlled version of this heater is the only
style designed to be operated with optional devices for
ON/OFF functions. The following options may be used
with the millivolt controlled heater. These options are not
packaged with the log set.
• Hand held Remote with receiver
• Wall thermostat with 15' wire
• Wall switch with 15' wire
• Hand held Thermostat Remote with receiver
Carefully inspect the contents for shipping damage. If any
parts are missing or damaged, immediately inform the
dealer from whom you purchased the appliance. Do not
attempt to install any part of the appliance unless you
have all parts in good condition.
WHAT YOU WILL NEED FOR INSTALLATION:
You should have the following items available before proceeding with installation:
• External regulator (for propane/LPG and 1/2 lb.
natural gas systems only)
• Piping which complies with local codes
• Sediment trap (recommended)
• Screwdriver
• Tee joint.
• Pipe sealant approved for use with propane/LPG
(Resistant to sulfur compounds)
• Drill with 5/32 bit
• Pipe wrench or appropriate size crescent wrench
set
• Manual shutoff valve
If the area in which the heater may be
operated does not meet the required volume
for indoor combustion air, combustion and
ventilation air shall be provided by one
of the methods described in the National
Fuel Gas Code, ANSI Z223.1/NFPA 54, the
WARNING
International Fuel Gas Code or applicable
local codes.
6
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
FIREPLACE and HEARTH DIMENSIONS
This appliance is for installation only in a solid-fuel burning masonry or UL127 factory-built
replace, vent free appliance, or in listed ventless rebox enclosure. It has been design certied
for these installations.
Exception: DO NOT install this appliance in a factory-built replace that includes instructions
WARNING
stating it has not been tested or should not be used with unvented gas logs.
PH Gas Logs
Use manufacturer’s installation and clearance require-
ments as dened in their manual.
The PH Series unvented room heater is approved for instal-
lation into the following unvented replaces:
GCUF(32,36,42) and VFR(32,36,42) Series Fireboxes
The PH Series unvented room heater may also be installed
into a Ventless Firebox Enclosure for Gas Fired Decorative
Type Unvented Room Heaters per ANSI Z21.91b.2004,
as long as rebox hearth dimensions meet the minimum
hearth dimensions shown below.
C
D
A
B
Figure 1
FP2530
MODEL A B C D
1
PH18 25"
(635 mm)
PH24 29"
(737 mm)
PH30 35"
(889 mm)
Figure 1 Hearth Minimum Dimensions
(330 mm)
(330 mm)
(330 mm)
13"
13"
13"
⁄2"
17
(445 mm)
1
⁄2"
19
(495 mm)
1
⁄2"
25
(648 mm)
17"
(432 mm)
17"
(432 mm)
17"
(432 mm)
Barriers such as the bottom of a glass door
frame placed in front of a gas log set can
change the air ow characteristics of the
replace which in turn can cause the unit
WARNING
to overheat and malfunction.
IMPORTANT INFORMATION FOR THE INSTALLATION OF THIS GAS LOG SET
The following are guidelines for placing a gas log set in
a replace that has a restrictive barrier along the bottom
front opening of the replace. Some examples of barri-
ers are glass/screen door frames and sunken/recessed
replaces.
Height of Minimum Depth of
Restriction (x) Fireplace/Firebox
No Restriction 13"
0" to 11⁄2" 16"
Greater than 11⁄2" to 3" 16"
Greater than 3" *
*Any barrier greater than 3" placed in front of the gas log
set is not recommended by the manufacturer.
NOTE: Non combustible material such as refractory brick
may be used to line the oor of the replace in order to raise
the height of the gas log set in relation to a restrictive barrier.
If the unit is raised, the minimum height dimension listed in
the homeowner’s manual must not be exceeded.
NOTE: If the log set is equipped with a remote receiver, a
restrictive barrier may reduce the battery life by increasing
the ambient temperature inside the replace. Placement
of the receiver outside of the replace will extend the
battery life.
The log set should
be placed against or
as near as possible
Glass door
frames with adjustable louvers
should have
the louvers
fully open while
the unit is in
operation
X
Height of restrictive barrier
caused by glass door
frames, recessed replaces, etc. from the base or
bottom surface of the unit.
(Refer to Table).
Figure 2 Reference Drawing of a Natural
Flame Log Set in an Enclosure
to the rear wall of the
replace
Depth of
Fireplace/
Firebox
(Refer to
Table)
FP2794
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
7
PH Gas Logs
►
ADEQUATE COMBUSTION VENTILATION
AIR
This heater shall not be installed in a conned space or
unusually tight construction unless provisions are provided
for adequate combustion and ventilation air.
The National Fuel Gas Code, (ANSI Z223.1/NFPA54),
denes a conned space as a space whose volume is less
than 50 cubic feet per 1,000 BTU per hour (4.8m
of the aggregate input rating of all appliances installed in
that space, and an unconned space as a space whose
volume is not less than 50 cubic feet per 1,000 BTU per
hour (4.8 m3 per kw) of the aggregate input rating of all
appliances installed in that space. Rooms communicating
directly with the space in which the appliances are installed,
through openings not furnished with doors, are considered
a part of a conned space.
Unusually tight construction is dened as construction
where:
a. Walls and ceilings exposed to the outside atmosphere
have a continuous water vapor retarder with a rating of
1 perm (6 x 10
gasketed or sealed, and
b. Weather stripping has been added to windows and
doors, and
c. Caulking or sealants are applied to areas such as joints
around window and door frames, between sole plates
and oors, between wall-ceiling joints, between wall
panels, at penetrations for plumbing, electrical and gas
lines and other openings.
11
kg per pa/sec-m2) or less with openings
3
per kw)
Counter
Figure 3
If the area in which the heater may be
operated does not meet the required volume
for indoor combustion air, combustion and
ventilation air shall be provided by one
of the methods described in the National
Fuel Gas Code, ANSI Z223.1/NFPA 54, the
WARNING
International Fuel Gas Code or applicable
local codes.
Fireplace
H
W
The following formula can be used to determine the maxi-
mum heater rating per the denition of unconned space:
BTU/Hr = (L1 + L2) Ft x (W) Ft x (H) Ft
50
Consider two connecting rooms with an open area between, with the following dimensions:
L1 = 151/2 Ft., L2 = 12 Ft., W = 12 Ft., H = 8 Ft.
BTU/Hr = (151/2 + 12) x (12) x (8)
50
If there were a door between the two rooms the calculation
would be based only on the room with the heater.
BTU/Hr = (151/2) x (12) x (8)
50
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Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
CLEARANCES and HEIGHT REQUIREMENTS
PH Gas Logs
The dimensions shown in Figures 4 through 12 and dened in the replace manufacturer's
instructions are minimum clearances to maintain when installing this heater. Left and right
clearances are determined when facing the front of the heater.
When heater is installed into a ventless rebox, minimum clearances, as specied by the ventless
rebox manufacturer, must be met.
WARNING
Follow these instructions carefully to ensure safe installation. Failure to follow instructions
exactly can create a re hazard.
Sidewall and ceiling clearances: The sides of the replace opening must be at least 16" from any combustible
wall. The ceiling must be at least 42" from the top of the
replace opening.
Heat
Resistant
Material
Measure This
Distance
42"
16"
FP1996
Figure 4 Sidewall and Ceiling Clearances
Heat resistant material (minimum requirements)
with no wooden mantel or other combustible
projection:
To install the gas logs into a replace with no wooden
mantel, shelf or other combustible projection above the
replace opening, measure the heat resistant material
height, per Figure 5, then see TABLE A.
Heat resistant materials such as slate and marble must be
at least 1/2" thick. Sheet metal should not be installed
onto combustible material.
Heater in
Fireplace or
Firebox
Figure 5Measure Heat Resistant Material
FP2922
Table A Heat Resistant Material Requirements with No
Mantel or Combustible Projection
Heat Resistant Material PH18/24 Requirements
Measurement for Safe Installation
12" or more Hood not required
8" or less than 12" Extend resistant material to
12" or install hood. Figure 5
Less than 8" Extend heat resistant material
to at least 8" and install hood.
Figure 5. OR, extend heat
resistant material to a height
of at least 12"
IMPORTANT: If you cannot meet these minimum clearanc-
es you must operate the heater with chimney ue damper
open. Refer to "Installing Vented Applications" found on
Page 12.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
9
PH Gas Logs
10"
8"
6"
2¹⁄₂"
8" 14¹⁄₂" 18⁵⁄₈" 22¹⁄₂" 26"
12"
12”
Min.
28”
10” or Less
INSTALLATION REQUIREMENTS
8" or More of Heat
Resistant Material
Hood
Heater in
Fireplace or
Figrebox
FP2923
Figure 6 Measure Heat Resistant Material for Mantel
Heat resistant material (minimum requirements) with
wooden mantel or other combustible projection:
To install the heater with a wooden mantel, shelf or other
combustible projection above, first measure the heat
resistant material shown in Figure 7, then see TABLE B.
Heat
Resistant
Material
Hood
Heater in
Fireplace or
Firebox
FP2534
Figure 7 Minimum Mantel Clearance with Hood
Example: A mantel may project from the wall a maximum
1
of 2
⁄2" at a minimum of 8" above the opening
and a maximum of 6" at a minimum of 141⁄2"
above the opening.
Table B Heat Resistant Material Heights and Mantel Location
Requirements for Safe
Heat Resistant
Material
Measurement
Installation with Wooden Mantel,
Shelf or Other Combustible
Projection
12" or more Hood not required. Observe
proles (side elevations) shown in
Figure 7
8" or less than
12"
Install hood (CABR/CABL) and
observe proles show in Figure 6;
OR extend heat resistant material
to at least 12" and observe proles
shown in Figure 7
Less than 8" Extend heat resistant material to
at least 8" and install hood (CABR/
CABL) and observe proles
shown in Figure 6; OR extend
heat resistant material to at least
12" and observe proles shown in
Figure 7.
Heat
Resistant
Material
Heater in
Fireplace or
Firebox
Figure 8 Minimum Mantel Clearance with No Hood
FP2535
Example: The bottom of the mantel may project from the
wall a maximum of 10" at a minimum of 28"
above the opening.
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Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
FLOOR CLEARANCE
PH Gas Logs
The gas log heater must be installed at least 5" above
any combustible ooring material, such as carpeting or
tile, which is closer than 14" to the base of the replace.
The minimum distance must be maintained from the top
surface of carpeting, tile, etc. Figure 9
OR,
FP2924
The gas log heater may be installed nearer to the oor if a
minimum of 14" of noncombustible material such as slate
or marble is installed between the base of the replace and
the combustible ooring. Figure 10 NOTE: The use of a
thermostat is prohibited in vented log applications.
Heater in Fireplace
or Firebox
Combustible
Material
5” Minimum
Figure 9 Minimum Clearance Above Combustible Flooring
Heater in
Fireplace or
This
Distance
May Now
be Less
than 5"
FP2925
Figure 10 Minimum Clearance Above Combustible Flooring with
Noncombustible Material Installed at Base of Fireplace
Firebox
Combustible
Material
14” Minimum
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
11
PH Gas Logs
INSTALLATION
BEFORE FULLY INSTALLING THE UNIT:
Turn OFF the gas supply to the replace or re-
•
box.
• Seal any fresh air vents and/or ash clean-out doors
located on the oor or wall of the replace. If left
unsealed, drafting may cause pilot outage or soot-
ing. Use a heat resistant sealant. Do not seal the
chimney ue damper.
Before installing in a solid fuel burning
fireplace, The chimney flue and firebox
must be cleaned of soot, creosote, ashes
and loose paint by a qualified chimney
WARNING
cleaner.
INSTALLING VENTED APPLICATIONS
Manual and millivolt controlled gas logs may be installed as
a vented decorative log set in compliance with ANSI Z21.60
and National Fuel Gas Code, Section 6.6 Since, the gas
logs are operated with the damper open, non-combustible
material and minimum mantel requirements do not apply.
NOTE: The use of a thermostat is prohibited in vented log
applications.
This appliance is for installation only in a solid
fuel burning replace (masonry replace or
manufactured fireplace) with a working
ue and constructed of noncombustible
material.
Exception: DO NOT install this appliance
in a factory-built fireplace that includes
WARNING
instructions stating that it has not been
tested or should not be used with unvented
gas logs. This log set may be installed as a
vented log set.
BEFORE INSTALLING THE APPLIANCE:
• Turn off gas supply to replace or rebox.
• Have the replace oor and chimney professionally
cleaned to remove ashes, soot, creosote or other
obstructions. Have this cleaning performed annually
after installation.
• Seal any fresh air vents or ash clean-out doors lo-
cated on oor or wall of replace. If not, drafting may
cause pilot outage or sooting. Use a heat-resistant
sealant. Do not seal chimney ue damper.
Install and operate the appliance as directed in this
manual.
DAMPER STOP INSTALLATION:
A damper stop must be provided with the unit. Contact your
dealer to obtain one. The damper stop must be installed as
shown in Figure 11 to prevent full closure of the replace
damper blade and provide a minimum 29 square inch ue
opening.
Damper
Stop
Damper
FP2538
Figure 11 Damper Stop Installation
(See Warning)
The replace and gas logs function as a
system. If the replace is spilling into the
room (check with a match or a smoke stick),
reposition the damper clamp until a positive
draft is obtained by opening the damper. If
negative pressure in home prevents having
WARNING
a positive draft, contact your dealer for
assistance.
PLACE AND SECURE APPLIANCE
You must secure the gas log heater to
the replace oor. If not, the entire unit
may move when you adjust the controls.
Movement of unit may cause shifting of
the gas logs which leads to sooting and
improper burning.
Special care is required if you are installing
the unit into a sunken replace. You must
raise the replace oor to allow access to
WARNING
gas log controls. This will insure adequate
air ow and guard against sooting. Raise
the replace oor using noncombustible
materials, as described in Placement in a
Fireplace with Restrictive Barrier on Page
7.
12
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
INSTALLATION
PH Gas Logs
ASSEMBLY PROCEDURE
1. Center the gas log unit in the replace or rebox.
2. Install Grate: Insert longest middle grate bar in one of
the two square holes in control panel. Figure 12. Be sure
grate is centered. Sit horizontal bar inside two hooks
on front of control panel. Figure 12. Make certain front
feet of grate are located inside front edge of replace
or rebox.
3. Anchor holes are located on the ange of the unit. Figure
12. After centering the burner correctly, mark the hole
positions on the replace/rebox oor. Drill two (2) 5/32"
diameter holes approximately 11⁄2" deep.
4. Anchor the unit to the replace/rebox oor using the
screws provided. Figure 13.
Screws
Hole for
Grate Bar
Use new black iron or steel pipe. Internally
tinned copper or copper tubing can be
used per National Fuel Code, section 2.6.3,
providing gas meets hydrogen sulfide
limits, and where permitted by local codes.
Gas piping system must be sized to provide
minimum inlet pressure (Listed on Data
Plate) at the maximum ow rate (BTU/Hr).
Undue pressure loss will occur if the pipe
is too small.
CAUTION
A manual shutoff valve must be installed
upstream of the appliance. Union tee
and plugged 1/8" NPT pressure tapping
point should be installed upstream of the
appliance. Figure 13
Stainless
Flexible
Tube
To
Heater
Valve
Pipe
Possible Locations
for Pressure
Tapping Point
Middle
Grate Bar
Hooks for
Grate
Horizontal
Grate Bar
Figure 12 Install Grate and Secure Heater to Floor
of Fireplace/Firebox
Anchor
Hole
CONNECT THE GAS LINE
NOTICE: A qualied gas appliance installer must
connect the heater to the gas supply. Consult all local
codes.
Pipe
Coupling
Manual Shutoff
Valve
Figure 13 Gas Connection
Gas
Supply
Inlet
FP2371
IMPORTANT: Hold heater valve rmly with a wrench to
prevent movement when connecting to inlet pipe.
CHECK GAS TYPE: The gas supply must
be the same as stated on the heater’s rating plate. If the gas supply is different, DO
NOT INSTALL THE HEATER. Contact your
WARNING
dealer for the correct model.
Connecting directly to an unregulated propane/LPG tank can cause an explosion.
WARNING
Always use an external regulator for all propane/LPG
heaters and high pressure one to two-pound systems
only, to reduce the supply tank pressure to a maximum of
13" w.c. This is in addition to the internal regulator in the
heater valve.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
13
PH Gas Logs
INSTALLATION
CHECK GAS PRESSURE
The heater gas inlet connection is a 3/8" NPT at the valve.
All units have the inlet connection on the right side, when
you face the unit. To connect from the opposite side, route
the pipe under the rear portion of the unit.
When tightening up the joint to the valve, hold the valve
securely to prevent movement.
Test all gas joints from the gas meter to the heater valve
for leaks using a gas analyzer or soap and water solution
after completing connection. DO NOT USE AN OPEN
FLAME.
Check the gas pressure with the appliance burning and
the control set to HIGH.
MANUAL CONTROL
Figure 14
The pressure regulator is preset and locked to discourage tampering. If the pressure is not as specied,
replace the regulator with the correct part from the parts
list in this manual.
Remove 1/8" NPT plug, located on side of regulator body.
Install tting and tubing to pressure gauge. After taking
pressure reading, reinstall test plug. Check for gas leaks.
MILLIVOLT CONTROL
Figure 15
The valve regulator controls the burner pressure which
should be checked at the pressure test point.
Turn captured screw counter clockwise two or thre turns
and then place tubing to pressure gauge over test point
(Use test point “OUT” closest to control knob). After taking pressure reading, be sure and turn captured screw
clockwise rmly to re-seal. Do not over torque. Check for
gas leaks.
Test Port “Out”
FP2372
NPT Test Plug
Figure 14 Manual Control Pressure
Test Point Location
Figure 15 Millivolt Control Pressure
Test Point Location
FP2499
14
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
ELECTRICAL WIRING - MILLIVOLT
Label all wires prior to disconnection when servicing controls.
Wiring errors can cause improper and dangerous operation.
Verify proper operation after servicing.
WARNING
On/Off
Switch
ODS Pilot
Wall
Switch
PH Gas Logs
ODS Pilot
Millivolt
Valve
On/Off Switch
TH = 3
TP = 1
TP/TH = 2
Switch
Figure 16 Wiring Diagram
The millivolt valve is a self-powered combination gas control
THAT DOES NOT REQUIRE 110 VAC TO OPERATE.
CONNECT OPTIONAL WALL SWITCH OR
THERMOSTAT(VENT FREE APPLICATIONS
ONLY)
Spade Terminal
FP2112
Optional Wall
Switch, Remote
Receiver or
Optional T-Stat
1. Use 18 AWG, two-wire cable, 20 feet maximum length.
At one end of the cable, connect both wires to the wall
switch or thermostat. At the other end, connect one wire
to TP/TH and one wire to TH. The color of the wires
does not matter. Or you can hook the wall switch or
thermostat to wires on the unit.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
15
PH Gas Logs
ELECTRICAL WIRING - MILLIVOLT
CONNECT OPTIONAL REMOTE RECEIVER
Follow instructions supplied with the remote.
Connect the wires to the two .25" male connectors
located on the left side of the valve when facing the
unit (Refer to Page 18, Figure 16). Do not let wire
touch grate or burner.
NOTE: Heat reduces battery life. You can protect
the receiver and extend battery life by mounting
the receiver in a wall or other location outside the
replace.
CHECK SYSTEM OPERATION
The millivolt system and individual components may be
checked with a millivolt meter having a 1-1000 mV range.
Conduct each check shown in chart by connecting meter
test leads to terminals as indicated.
A. COMPLETE MILLIVOLT SYSTEM CHECK
(“A” Reading - On/Off Switch contacts CLOSED -
Control Knob “ON” - Main burner should come
ON)
a. If the reading is more than 175 millivolts and the
automatic valve still does not come on, replace the
control.
b. If the closed circuit reading (“A” reading) is less than
175 millivolts, determine cause for low reading, pro-
ceed to Section B below.
B. Thermopile Output Reading Check
(“B” Reading - On/Off Switch contacts OPEN Main burner OFF)
1. Check gas pressure to the unit. If gas pressure
is within minimum and maximum on data plate,
then check pilot voltage, 500 millivolts minimum.
If the minimum millivolt reading is not obtainable,
replace pilot.
Connect Switch or Meter
Check Meter Leads Thermostat Reading
Test To Test To Terminals Contacts Should Be
A Complete 2 & 3 Closed Minimum 175mV
System
B Thermopile 1 & 2 Open Minimum 500mV
Output
16
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
LOG PLACEMENT
The positioning of the logs are critical to the safe and clean operation of this heater. Sooting and
other problems may result if the logs are not properly and rmly positioned in the appliance.
Never add additional logs or embellishments such as pine cones, vermiculite or rock wool to
the heater. Only use the logs supplied with the unit.
Failure to position the parts in accordance with diagrams below or to use only parts specically
WARNING
approved for this heater may result in property damage or personal injury.
Rear Log #1
PLACE PH18-R LOGS
1. Place Rear Log (#1) on rear support.
Figure 17.
2. Place Left Middle Log (#2) on middle
support and burner. Figure 18
3. Place Right Middle Log (#3) on middle
support. Figure 18
NOTE: Logs #1, #2 and #3 have ridges on
the bottom which secure the logs to burner
frame. After installing each log, check to be
sure it is stable.
PH Gas Logs
Left Middle Log #2
Figure 17
Right Middle Log #3
LG1084
DO NOT sprinkle
volcanic rock on the
logs or around the pilot
or the main burner. This
may cause sooting.
Only place volcanic
rock on the oor of the
replace.
During initial operation
of the new heater,
CAUTION
burning logs will give off
a paper burning smell
and orange ames will
be present. Simply open
the windows for a few
hours to vent the odor.
LG1085
Figure 18
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17
PH Gas Logs
LOG PLACEMENT
4. Place Front Log (#4) in between
burner and grate so that notched
areas t between grate supports.
Figure 19
Figure 19
LG1086
Front Log #4
5. Rest Left Top Log (#5) on front
and rear log cutouts. Figure 19
6. Rest Right Top Log (#6) on front
and rear log cutouts. Figure 20
Left Top Log #5
Right Top Log #6
18
Figure 20
LG1087
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
LOG PLACEMENT
The positioning of the logs are critical to the safe and clean operation of this heater. Sooting and
other problems may result if the logs are not properly and rmly positioned in the appliance.
Never add additional logs or embellishments such as pine cones, vermiculite or rock wool to
the heater. Only use the logs supplied with the unit.
Failure to position the parts in accordance with diagrams below or to use only parts specically
WARNING
approved for this heater may result in property damage or personal injury.
Rear Log #1
PLACE PH24-R LOGS
1. Place Rear Log (#1) on rear support. Figure 21
2. Place Left Middle Log (#2) on middle support and
burner. Figure 22
3. Place Right Middle Log (#3) on middle support.
Figure 22
NOTE: Logs #1, #2 and #3 have ridges on the bottom
which secure the logs to burner frame. After installing
each log, check to be sure it is stable.
PH Gas Logs
Left Middle Log #2
Figure 21
Right Middle Log #3
LG1089
LG1088
DO NOT sprinkle
volcanic rock on the
logs or around the pilot
or the main burner. This
may cause sooting.
Only place volcanic
rock on the oor of the
replace.
During initial operation
of the new heater,
CAUTION
burning logs will give off
a paper burning smell
and orange ames will
be present. Simply open
the windows for a few
hours to vent the odor.
Figure 22
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
19
PH Gas Logs
LOG PLACEMENT
4. Place Front Log (#4) in
between burner and grate so
that notched areas t between
grate supports. Figure 23
Figure 23
LG1090
Front Log #4
5. Rest Left Top Log (#5) on
front and rear log cutouts.
Figure 24
6. Rest Right Top Log (#6) on
front and rear log cutouts.
Figure 24
Left Top Log #5
Figure 24
Right Top Log #6
LG1091
20
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
LOG PLACEMENT
The positioning of the logs are critical to the safe and clean operation of this heater. Sooting and
other problems may result if the logs are not properly and rmly positioned in the appliance.
Never add additional logs or embellishments such as pine cones, vermiculite or rock wool to
the heater. Only use the logs supplied with the unit.
Failure to position the parts in accordance with diagrams below or to use only parts specically
WARNING
approved for this heater may result in property damage or personal injury.
Rear Log #1
PLACE PH30-R LOGS
1. Place Rear Log (#1) on rear support. Figure 25
2. Place Left Middle Log (#2) on middle support and
burner. Figure 26
3. Place Right Middle Log (#3) on middle support.
Figure 26
NOTE: Logs #1, #2 and #3 have ridges on the
bottom which secure the logs to burner frame.
After installing each log, check to be sure it
is stable.
PH Gas Logs
Left Middle Log #2
Figure 25
LG1092
Right Middle
Log #3
LG1093
Figure 26
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
21
PH Gas Logs
4. Place Front Log (#4) in between
burner and grate so that notched
areas t between grate supports.
Figure 27
Figure 27
LOG PLACEMENT
LG1094
Front Log #4
Left Top Log #5
Right Top
Log #6
DO NOT sprinkle volcanic rock on the logs
or around the pilot or the main burner. This
may cause sooting. Only place volcanic
rock on the oor of the replace.
During initial operation of the new heater,
burning logs will give off a paper burning
smell and orange ames will be present.
CAUTION
Simply open the windows for a few hours
to vent the odor.
5. Rest Left Top Log (#5) on front
and rear log cutouts. Figure 28
6. Rest Right Top Log (#6) on front
and rear log cutouts. Figure 28
Figure 28
LG1095
22
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
FLAME APPEARANCE
PH Gas Logs
Flames from the pilot, front and rear burner should be
visually checked as soon as the heater is installed.
In addition, periodically check the ames visually during
operation.
CHECK THE PILOT FLAME
The pilot ame must always be present when the
heater is in operation. It should just touch the top of the
thermocouple tip for natural. Refer to Figures 29 and 31
for correct pilot ame appearance.
MILLIVOLT CONTROL
Thermocouple
for Natural Gas
If the pilot ame does not touch the thermocouple, then
the main burner cannot function reliably. Refer to Figures
30 and 32 for incorrect pilot ame appearance
MANUAL & HI/LO CONTROL
Thermocouple
for Natural Gas
Thermocouple
for LP
Thermocouple
for LP
Figure 29 Correct Pilot Flame Appearance
Thermocouple
for Natural Gas
Thermocouple
for LP
Figure 30 Incorrect Pilot Flame Appearance
FP2272
Figure 31 Correct Pilot Flame Appearance
Thermocouple
for Natural Gas
Thermocouple
for LP
FP2273
FP2502
Figure 32 Incorrect Pilot Flame Appearance
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
23
PH Gas Logs
FLAME APPEARANCE
In normal operation at full rate after 15 minutes, the
following ame appearances should be observed:
Figure 33 Correct Burner Flame Appearance
The left and right ames should be yellow and extend 1"
to 2" above the log top surfaces. The yellow ames should
not contact the logs.
LG1099
24
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
CHECKING THE BURNER FLAME
OPERATING INSTRUCTIONS
Avoid any drafts that alter burner ame patterns. Do
not allow fans to blow directly into the replace. Do not
place a blower inside the burn area of the rebox. Ceiling
fans may create drafts that alter ame patterns. Sooting
and improper burning will result.
During manufacturing, fabricating and shipping, various
components of this appliance are treated with certain oils,
lms or bonding agents. These chemicals are not harmful,
but may produce annoying smoke and smells as they are
burned off during the initial operation of the appliance,
possibly causing headaches or eye or lung irritation. This
is a normal and temporary occurrence.
The initial break-in operation should last two to three hours
with the burner at the highest setting. Provide maximum
ventilation by opening windows or doors to allow odors to
dissipate. Any odors remaining after this initial break-in will
be slight and will disappear with continued use.
This appliance must not be used with glass doors in the
closed position. This can lead to pilot outages and severe
sooting outside the replace.
PH Gas Logs
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
25
PH Gas Logs
OPERATING INSTRUCTIONS
FOR YOUR SAFETY, READ BEFORE LIGHTING
If you do not follow these instruction
exactly, a fire or explosion may result
causing property damage, personal injury
or loss of life.
WARNING
A. This appliance is equipped with an ignition device which automatically lights the pilot. Do not try to
light the unit by hand.
B. BEFORE OPERATING smell all around the appliance area for gas. Be sure to smell next to the oor
because some gas is heavier than air and will settle on the oor.
WHAT TO DO IF YOU SMELL GAS:
• Do not attempt to light any appliance.
• Do not touch any electric switch; do not use any phone in your building.
• Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's instruc-
tions.
• If you cannot reach your gas supplier, call the re department.
C. Use only your hand to push in, or turn the gas control knob. Never use tools. If the knob will not push
in or turn by hand, don't try to repair it. Call a qualied service technician. Force or attempted repair
may result in a re or explosion.
D. Do not use this appliance if any part of it has been under water. Immediately call a qualied service
technician to inspect the appliance and to replace any part of the control system and any gas control
that has been under water.
Piezo Ignitor
Switch
Location of Piezo Ignitor, Control Knobs
and Switch on Millivolt Unit
26
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
LG1097
Control
Knobs
OPERATING INSTRUCTIONS
MANUAL CONTROL LIGHTING INSTRUCTIONS
1. STOP! Read the safety information.
2. Make sure the manual shutoff valve is fully open.
3. This heater is equipped with an ignition device (piezo) which automatically
lights the pilot.
4. Refer to Page 26 for the location of the piezo ignitor and control knob. Push
in gas control knob slightly and turn control knob clockwise
position.
NOTE: Knob cannot be turned to OFF unless knob is pushed in slightly. Do
not force.
5. Wait 5 minutes to clear out any gas. Then smell for gas, including near the
oor. If you smell gas STOP! Follow the instructions under “What to Do if You
Smell Gas”, Page 26. If you do not smell gas, go to the next step.
6. From OFF position, push in gas control knob slightly and turn counterclock-
wise
to the IGN position. Figure 34. Push in and hold control knob for 5
seconds.
NOTE: If you are running the heater for the rst time, it will be necessary to
press in the control knob for 30 seconds to allow air to bleed out of the gas
piping.
7. With the control knob pushed in, push and release the piezo ignitor button to
light the ODS pilot. The pilot is located on the left side of the heater, behind
the middle log and in front of the back log. If piezo ignitor does not light the
pilot, refer to “Match Lighting Instructions”, Page 29
8. Hold the control knob in for an additional 10 seconds to prevent the ODS pilot
from shutting off the gas while the thermocouple is warming up.
9. Release the control knob.
• If the knob does not pop out when released, stop and immediately call your
service technician or gas supplier.
• If the ODS pilot will not stay lit after several tries, push and turn the gas
control knob clockwise to OFF and wait 15 seconds. Repeat steps 6
through 9.
10. Push in control knob and turn counterclockwise to the HIGH setting. At
this location the control knob will pop out when positioned correctly. The knob
can now be positioned at any position between HIGH and LOW. Figures 35
and 36
to the OFF
Rotate
Figure 34 IGN Position
Rotate
Figure 35 HIGH Position
Rotate
Figure 36 LOW Position
PH Gas Logs
Push
Push
Wait 30 seconds before readjusting the
heater when the control knob has been
turned down to a lower setting.
WARNING
TO TURN OFF GAS TO HEATER
1. Turn control knob clockwise
2. If applicable: Turn off all electric power to the heater.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
to OFF position to completely shut off the heater.
27
PH Gas Logs
OPERATING INSTRUCTIONS
MILLIVOLT CONTROL LIGHTING INSTRUCTIONS
1. STOP! Read the safety information label.
2. Make sure the manual shutoff valve is fully open.
3. This gas log set is equipped with an ignition device (piezo) which automatically lights the pilot. If piezo
ignitor does not light the pilot, refer to instructions for Match Lighting Instructions, Page 29.
4. Turn gas control knob clockwise to the OFF position, set thermostat to lowest setting and turn ON/OFF
switch to OFF position.
5. Wait (5) minutes to clear out any gas. Then smell for gas, including near the oor. If you smell gas,
STOP! Follow What to Do if You Smell Gas, Page 26. If you don't smell gas, go to next step.
6. From OFF position, turn the gas control knob counterclockwise
knob for 5 seconds. NOTE: If you are running the heater for the rst time, it may be necessary to
press in the control knob for 30 seconds orlonger to allow air to bleed out of the gas piping.
7. With the control knob pushed in, push in and release the piezo ignitor button to light the pilot.
8. Continue pushing the control knob in for a further 60 seconds to prevent the ame detector from shutting off the gas while the probe is warming up. Release the control knob.
9. Turn gas control knob counterclockwise
to the ON position.
10. After the pilot has been lit for one minute, the burners can be turned on. Turn the ON/OFF switch to ON
position or adjust thermostat to desired setting. NOTE: To use the thermostat function (if installed)
the control knob must be set to “ON” and ON/OFF switch must in the “OFF” position.
11. If the gas logs will not operate, follow the instructions To Turn Off Gas To Heater below and call your
service technician or gas supplier.
to IGN position. Push in control
ON/OFF
Switch
Piezo
FP2275
Pilot
Millivolt Controls
Hi/Lo Control
Ignitor Pilot
Control
FP2927
TO TURN OFF GAS TO HEATER
1. Turn control knob clockwise to OFF position to completely shut off the heater.
2. If applicable: Turn ON/OFF switch to OFF position and/or set thermostat (if present) to lowest setting.
3. If applicable: Turn off all electric power to the heater.
28
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
OPERATING INSTRUCTIONS and CLEANING & SERVICING
PH Gas Logs
MATCH LIGHTING INSTRUCTIONS
1. Remove any items necessary for easy access to the pilot (for example: logs, screens, etc.).
2. Follow appropriate lighting instructions found previously. Instead of pushing and releasing the piezo
button, light a match and hold the ame to the end of the pilot and ignite the pilot.
3. After control knob has been released and pilot stays lit, reinstall any items that were removed for pilot
access.
4. Call a qualied service technician for repair or replacement of the piezo ignitor.
Turn off heater and allow to cool before
cleaning. Disconnect electrical power
before cleaning or servicing.
WARNING
CLEANING AND SERVICING
Annual inspection and cleaning by your dealer or qualied service technician is recommended to prevent
malfunction and/or sooting.
Remove logs, handling carefully by holding gently at each
end. Gloves are recommended to prevent skin irritation
from ceramic bers. If skin becomes irritated, wash gently with soap and water. Refer to manual for correct log
placement.
PERIODIC CLEANING - Refer to parts diagram for location of items discussed below.
• Do not use cleaning uid to clean logs or any part of
heater.
• Brush logs with soft bristle brush or vacuum with
brush attachment.
• Vacuum loose particles and dust from the front and
rear burner, control and piezo covers and grate
weldment.
• Inspect and clean burner air intake holes. Remove
lint or particles with vacuum, brush, or pipe cleaners.
Failure to keep air intake holes clean will result
in sooting and poor combustion.
• External case should be dusted and wiped with a
wet soapy cloth.
ANNUAL CLEANING/INSPECTION - Refer to parts diagram for location of items discussed below.
• Inspect and clean burner air intake holes. Remove
lint or particles with vacuum, brush or pipe cleaners.
Failure to keep air intake holes clean will result
in sooting and poor combustion.
• Inspect and clean all burner ports.
• Inspect ODS pilot for operation and accumulation of
lint at air intake holes.
• Verify ame pattern and log placement for proper
operation.
• Verify smooth and responsive ignition of main burner
and rear burner.
• Replace battery in remote control device.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
29
PH Gas Logs
TROUBLESHOOTING
Turn off appliance and allow to cool before cleaning.
Only a qualied service person should service and repair
the heater.
WARNING
NOTE: All troubleshooting items are listed in order of operation.
Problem
When ignitor button is
pressed, there is not spark
at ODS/pilot.
Appliance produces un-
wanted odors.
Appliance shuts off during
use.
Gas odor even when
control knob is in OFF
position.
When ignitor button is
pressed, there is spark at
ODS/pilot, but no ignition.
Possible Cause
1. Ignitor electrode positioned wrong.
2. Ignitor electrode is broken.
3. Ignitor electrode not connected to
ignitor cable.
4. Ignitor cable pinched or wet. Keep
ignitor cable dry.
5. Broken ignitor cable.
6. Bad piezo ignitor.
1. Appliance burning vapors from
paint, hair spray, glues, etc.
2. Gas leak.
3. Initial burn off.
1. Not enough fresh air is available for
ODS/pilot to operate.
2. Low line pressure.
3. ODS/pilot is partially clogged.
4. Defective thermopile.
5. Restrictions in incoming air ow.
1. Gas leak.
2. Control valve defective.
1. Gas supply turned off or manual
shutoff valve closed.
2. Control knob not in PILOT position.
3. Control knob not pressed in while in
PILOT position.
4. Air in gas lines when installed.
5. ODS/pilot is clogged.
6. Gas regulator setting is not correct.
Solution
1. Replace ignitor.
2. Replace ignitor.
3. Reconnect ignitor cable.
4. Free ignitor cable if pinched by any
metal or tubing.
5. Replace ignitor cable.
6. Replace piezo ignitor.
1. Ventilate room. Stop using odor causing
products while heater is running.
2. Locate and correct leaks.
3. Ventilate room and turn unit on high until
odor is gone. Odor should be gone after
6 hours of continuous use.
1. open window and/or door for ventilation.
2. Contact local gas company.
3. Clean ODS/pilot.
4. Check wire connections. Check output
should be 500 mV across TH/TP and TP
terminals with ON/OFF switches off.
5. Check for bottom riser on glass door,
sunken replace, excessive lava rock/
cinders densely packed against grate.
1. Locate and correct all leaks.
2. Replace control valve.
1. Turn on gas supply or open manual
shutoff valve.
2. Turn control knob to PILOT position.
3. Press in control knob while in PILOT
position.
4. Continue holding down control knob.
Repeat igniting operation until air is
removed.
5. Replace ODS/pilot assembly or get it
services.
6. Check incoming pressure. Replace gas
regulator.
30
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
TROUBLESHOOTING
PH Gas Logs
Problem
ODS/pilot lights, but ame
goes out when control
knob is released.
Burner does not light after
ODS/pilot is lit.
Burner backres during
combustion.
Slight smoke or odor dur-
ing initial operation.
Logs appear to smoke
after initial operation.
Heater produces a whistling noise when burner is
lit.
No gas to pilot.
Possible Cause
1. Control knob not fully pressed in.
2. Control knob not pressed in long
enough.
3. Manual shutoff valve not fully open.
4. Thermocouple connection loose at
control valve.
5. Pilot ame not touching thermo-
couple, which allows thermocouple
to cool, causing pilot ame to go out.
This problem could be caused by
either low gas pressure, or a dirty or
partially clogged ODS/pilot.
6. Thermocouple damaged.
7. Control valve damaged.
1. Burner orice is clogged.
2. Burner orice diameter is too small.
3. Inlet gas pressure is too low.
1. Manifold Pressure is too low.
2. Burner orice is clogged.
1. Burner orice is clogged or damaged.
2. Burner is damaged.
3. Gas regulator is defective.
1. Vapors from paint or curing process
of logs.
1. Turning control knob to HIGH position when burner is cold.
2. Air in gas line.
3. Dirty or partially clogged burner
orices.
1. LP regulator shut down due to inlet
pressure too high.
Solution
1. Press in control knob fully.
2. After ODS/pilot lights, keep control knob
pressed in for 30 seconds.
3. Fully open manual shutoff valve.
4. Hand tighten thermocouple connection
until snug, then tighten 1/4 turn more.
5. Contact local gas company.
6. Replace thermocouple.
7. Replace control valve.
1. Clean burner or replace burner orice.
2. Replace burner orice.
3. Contact qualied service person.
1. Contact local gas company.
2. Clean burner or replace burner orice.
1. Clean burner or replace burner orice.
2. Replace burner.
3. Replace gas regulator.
1. Problem will stop after a few hours
of operation. Run the heater with the
damper open if you have one, or open a
window for the rst few hours.
2. Log heater is intended to be smokeless. Turn OFF heater and call qualied
service person.
1. Turn control knob to LOW position and
let warm up for a minute.
2. Operate burner until air is removed from
line. Have gas line checked by local gas
company.
3. Clean burner or replace burner orice.
1. Verify LP tank regulator is installed and
set at 11" to 13" w.c.
2. Replace regulator on heater.
If the gas quality is bad, your pilot may not
stay lit, the burners may produce soot and
the heater may backre when lit. If the gas
quality or pressure is low, contact your local
WARNING
gas supplier immediately.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
31
PH Gas Logs
SERVICE PARTS
Service Parts
18” Hearth Kit
PH18NM (Natural Gas Manual Control)
PH18NV (Natural Gas Millivolt Control)
1
PH18
Beginning Manufacturing Date: NA
Ending Manufacturing Date: Active
PH18PM (Propane Manual Control)
PH18PV (Propane Millivolt Control)
2
12
3
4
5
6
Part number list on following page.
11
10
7
8
9
01/19
32
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
SERVICE PARTS
PH Gas Logs
Service Parts
Beginning Manufacturing Date: NA
Ending Manufacturing Date: Active
IMPORTANT: THIS IS DATED INFORMATION. Parts must be ordered from a dealer or
distributor.
model number and serial number when requesting service parts from your dealer or distributor.
ITEM DESCRIPTION COMMENTS PART NUMBER
Hearth and Home Technologies does not sell directly to consumers. Provide
1 Burner
ODS Pilot Assembly (Manual Control)
2
ODS Pilot Assembly (Millivolt Control)
Pilot Tube 49D0050K Y
3 Grate 65D2001K
4 Piezo Ignitor SRV14D0503 Y
Piezo Wire SRV00K0632 Y
5 On/Off Switch Millivolt Control SRV32D0232 Y
6 Knob Control Manual Control SRV18D0603
7 Knob Extension, On/Off Millivolt Control SRV37D0010
8 Knob Extension, Hi/Lo Millivolt Control SRV37D0011
9 Regulator (Manual Control)
10 Control Valve (Manual Control)
11 Control Valve (Millivolt Control)
Injector, Manual Control
12
Injector, Millivolt Control
Regulator to Valve Tube Manual Control SRV65D1004
Valve to Burner Tube
Pilot Regulator (Millivolt Control) NG Only SRV14D0469
NG SRV65D1053
Propane SRV65D1054
NG SRV26D2529 Y
Propane SRV14D0476 Y
NG SRV14D0473 Y
Propane SRV14D0477 Y
NG SRV65D2039
Propane SRV24D0306 Y
NG SRV30D0201 Y
Propane SRV30D0202
NG SRV14D0467 Y
Propane SRV14D0468 Y
NG SRV56D0613
Propane SRV20H3144
NG SRV58D0051 Y
Propane SRV20H3144
No longer available
Millivolt Control 65D1007K
65D1005K
PH18
Stocked
at Depot
Y
Y
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
33
PH Gas Logs
SERVICE PARTS
13.2
Service Parts
13.5
13.1
PH18
Beginning Manufacturing Date: NA
Ending Manufacturing Date: Active
13.6
13.3
13.4
IMPORTANT: THIS IS DATED INFORMATION. Parts must be ordered from a dealer or
distributor.
model number and serial number when requesting service parts from your dealer or distributor.
ITEM DESCRIPTION COMMENTS PART NUMBER
13.1 Rear Log 20303849K
13.2 Left Middle Log 20303850K
13.3 Right Middle Log 20303851K
13.4 Front Log 20303852K
13.5 Left Top Log 20303853K
13.6 Right Top Log 20303854K
Hearth and Home Technologies does not sell directly to consumers. Provide
Log Assembly
13
(Required to complete burner assembly, Sold seperately)
18” Mountain Cedar
PH18R
Stocked
at Depot
34
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
SERVICE PARTS
PH Gas Logs
Service Parts
24” Hearth Kit
PH24NM (Natural Gas Manual Control)
PH24NV (Natural Gas Millivolt Control)
1
PH24
Beginning Manufacturing Date: NA
Ending Manufacturing Date: Active
PH24PM (Propane Manual Control)
PH24PV (Propane Millivolt Control)
2
12
3
11
10
4
5
6
7
8
9
Part number list on following page.
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
01/19
35
PH Gas Logs
SERVICE PARTS
Service Parts
Beginning Manufacturing Date: NA
Ending Manufacturing Date: Active
IMPORTANT: THIS IS DATED INFORMATION. Parts must be ordered from a dealer or
distributor.
model number and serial number when requesting service parts from your dealer or distributor.
ITEM DESCRIPTION COMMENTS PART NUMBER
Hearth and Home Technologies does not sell directly to consumers. Provide
1 Burner
ODS Pilot Assembly (Manual Control)
2
ODS Pilot Assembly (Millivolt Control)
Pilot Tube 49D0050K Y
3 Grate 65D2002K
4 Piezo Ignitor SRV14D0503 Y
Piezo Wire SRV00K0632 Y
5 On/Off Switch Millivolt Control SRV32D0232 Y
6 Knob Control Manual Control SRV18D0603
7 Knob Extension, On/Off Millivolt Control SRV37D0010
8 Knob Extension, Hi/Lo Millivolt Control SRV37D0011
9 Regulator (Manual Control)
10 Control Valve (Manual Control)
11 Control Valve (Millivolt Control)
Injector, Manual Control
12
Injector, Millivolt Control
Regulator to Valve Tube Manual Control SRV65D1004
Valve to Burner Tube
Pilot Regulator (Millivolt Control) NG Only SRV14D0469
NG SRV65D1055 Y
Propane SRV65D1056
NG SRV26D2529 Y
Propane SRV14D0476 Y
NG SRV14D0473 Y
Propane SRV14D0477 Y
NG SRV65D2039
Propane SRV24D0306 Y
NG SRV30D0201 Y
Propane SRV30D0202
NG SRV14D0467 Y
Propane SRV14D0468 Y
NG SRV20H3152
Propane SRV57D0612 Y
NG SRV57D0209 Y
Propane SRV57D0612 Y
Manual Control 65D1006K
Millivolt Control 65D1008K
PH24
Stocked
at Depot
Y
Y
36
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
SERVICE PARTS
PH Gas Logs
Service Parts
Beginning Manufacturing Date: NA
Ending Manufacturing Date: Active
IMPORTANT: THIS IS DATED INFORMATION. Parts must be ordered from a dealer or
distributor.
model number and serial number when requesting service parts from your dealer or distributor.
ITEM DESCRIPTION COMMENTS PART NUMBER
Hearth and Home Technologies does not sell directly to consumers. Provide
13.1
13.6
13.5
13.3
13.2
13.4
Log Assembly
13
(Required to complete burner assembly, Sold seperately)
13.1 Rear Log 20303855K
13.2 Left Middle Log 20303856K
13.3 Right Middle Log 20303857K
13.4 Front Log 20303858K
13.5 Left Top Log 20303859K
13.6 Right Top Log 20303859K
24” Mountain Cedar
PH24R
PH24
Stocked
at Depot
14.1
14.6
14.5
14.3
14.2
14.4
Log Assembly
14
(Required to complete burner assembly, Sold seperately)
14.1 Rear Log 65D2015K
14.2 Left Middle Log 65D2017K
14.3 Right Middle Log 65D2018K
14.4 Front Log 65D2016K
14.5 Left Top Log 65D2013K
14.6 Right Top Log 65D2014K
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
30” Mountain Cedar
PH30R
37
PH Gas Logs
Accessories
Flex Connector Flexcon 30 All Models
Wall Switch Kit MVSW Millivolt Only
Wall Thermostat Kit WT Millivolt Only
Remote Controls RCMT, RCB, RCBE Millivolt Only
Thermostat Remote Controls RCT, RCST, RCSITE, WWTA, WWTD Millivolt Only
ACCESSORIES
38
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
MASSACHUSETTS RESIDENTS ONLY
Please read and follow these special requirements
NOTE REGARDING VENTED PRODUCTS
This product must be installed by a licensed plumber or
gas tter when installed within the Commonwealth of
Massachusetts.
Any residence with a direct vent product must have a carbon
monoxide (CO) detector installed in the residence.
Installation of the replace or vented gas log in the State
of Massachusetts requires the damper to be permanently
removed or welded in the fully open position.
In addition, a naturally vented gas log may not be installed in a
bedroom or bathroom in the State of Massachusetts.
Flex line installation must not exceed 36 inches and must have
a T shutoff valve.
NOTE REGARDING VENT FREE PRODUCTS
This product must be installed by a licensed plumber or
gas tter when installed within the Commonwealth of
Massachusetts.
In addition, vent free products may not be installed in a
bedroom or bathroom regardless of size or type in the State of
Massachusetts.
Flex line installation must not exceed 36 inches and must have
a T shutoff valve.
CARBON MONOXIDE DETECTOR REQUIREMENTS
(2) Revise 10.8.3 by adding the following additional
requirements:
(a) For all side wall horizontally vented gas fueled equipment
installed in every dwelling, building or structure used in whole
or in part for residential purposes, including those owned
or operated by the Commonwealth and where the side wall
exhaust vent termination is less than seven (7) feet above
nished grade in the area of the venting, including but not
limited to decks and porches, the following requirements shall
be satised:
1. Installation of carbon monoxide detectors. At the time
of installation of the side wall horizontal vented gas fueled
equipment, the installing plumber or gas tter shall observe
that a hard wired carbon monoxide detector with an alarm and
battery back-up is installed on the oor level where the gas
equipment is to be installed. In addition, the installing plumber
or gas tter shall observe that a battery operated or hard wired
carbon monoxide detector with an alarm is installed on each
additional level of the dwelling, building or structure served
by the side wall horizontal vented gas fueled equipment. It
shall be the responsibility of the property owner to secure the
services of qualied licensed professionals for the installation
of hard wired carbon monoxide detectors
a. In the event that the side wall horizontally vented gas
fueled equipment is installed in a crawl space or an attic, the
hard wired carbon monoxide detector with alarm and battery
back-up may be installed on the next adjacent oor level.
b. In the event that the requirements of this subdivision
can not be met at the time of completion of installation, the
owner shall have a period of thirty (30) days to comply with the
above requirements; provided, however, that during said thirty
(30) day period, a battery operated carbon monoxide detector
with an alarm shall be installed.
2. Approved Carbon Monoxide Detectors. Each carbon
monoxide detector as required in accordance with the above
provisions shall comply with NFPA 720 and be ANSI/UL 2034
listed and IAS certied.
3. Signage. A metal or plastic identication plate shall
be permanently mounted to the exterior of the building at a
minimum height of eight (8) feet above grade directly in line
with the exhaust vent terminal for the horizontally vented gas
fueled heating appliance or equipment. The sign shall read, in
print size no less than one-half (1/2) inch in size, “GAS VENT
DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS.”
4. Inspection. The state or local gas inspector of the
side wall horizontally vented gas fueled equipment shall not
approve the installation unless, upon inspection, the inspector
observes carbon monoxide detectors and signage installed
in accordance with the provisions of 248 CMR 5.08(2)(a)1
through 4.
(b) Exemptions: The following equipment is exempt from 248
CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled "Equipment
Not Required To Be Vented" in the most current edition of
NFPA 54 as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled
equipment installed in a room or structure separate from the
dwelling, building or structure used in whole or in part for
residential purposes.
(c) Manufacturer requirements — Gas Equipment Venting
System Provided. When the manufacturer of Product
Approved side wall horizontally vented gas equipment provides
a venting system design or venting system components with
the equipment, the instructions provided by the manufacturer
for installation of the equipment and the venting system shall
include:
1. Detailed instructions for the installation of the venting
system design or the venting system components; and
2. A complete parts list for the venting system design or
venting system.
(d) Manufacturer requirements — Gas Equipment Venting
System Not Provided. When the manufacturer of a Product
Approved side wall horizontally vented gas fueled equipment
does not provide the parts for venting the ue gases, but
identies “special venting systems,” the following requirements
shall be satised by the manufacturer:
1. The referenced "special venting system" instructions
shall be included with the appliance or equipment installation
instructions; and
2. The “special venting systems” shall be Product Approved
by the Board, and the instructions for that system shall include
a parts list and detailed installation instructions.
(e) A copy of all installation instructions for all Product
Approved side wall horizontally vented gas fueled equipment,
all venting instructions, all parts lists for venting instructions,
and/or all venting design
PH Gas Logs
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
39
PH Gas Logs
LIMITED LIFETIME WARRANTY
LIFETIME WARRANTY
The following components are warranted for life to the original owner, subject of proof of purchase: Firebox, Combustion
Chamber, Heat Exchanger, Grate, and Stainless Steel Burners.
FIVE YEAR WARRANTY
The following components are warranted for 5 years to the original owner, subject of proof of purchase: Vent Free Ceramic
Fiber Logs and Aluminized Burners.
BASIC WARRANTY
Monessen warrants the components and materials in your gas appliance to be free from manufacturing and material
defects for a period of two years from date of installation. After installation, if any of the components manufactured by
Monessen in the appliance are found to be defective in materials or workmanship, Monessen will, at its option, replace
or repair the defective components at no charge to the original owner. Monessen will also pay for reasonable labor costs
incurred in replacing or repairing such components for a period of two years from the date of installation. Any products
presented for warranty repair must be accompanied by a dated proof of purchase.
This Limited Lifetime Warranty will be void if the appliance is not installed by a qualied installer in accordance with the
installation instructions. The Limited Lifetime Warranty will also be void if the appliance is not operated and maintained
according to the operating instructions supplied with the appliance, and does not extend to (1) rebox/burner assem-
bly damage by accident, neglect, misuse, abuse, alteration, negligence of others, including the installation thereof by
unqualied installers, (2) the costs of removal, reinstallation or transportation of defective parts on the appliance, or (3)
incidental or consequential damage. All service work must be performed by an authorized service representative.
This warranty is expressly in lieu of other warranties, express or implied, including the warranty of merchantability of
tness for purpose and of all other obligations or liabilities. Monessen does not assume for it any other obligations or
liability in connection with the sale or use of the appliance. In states that do not allow limitations on how long an implied
warranty lasts, or do not allow exclusion of indirect damage, those limitations of exclusions may not apply to you. You
may also have additional rights not covered in this Limited Lifetime Warranty.
Monessen reserves the right to investigate any and all claims against the Limited Lifetime Warranty and decide upon
method of settlement.
IF WARRANTY SERVICE IS NEEDED...
1. Contact your supplier. Make sure you have your warranty, your sales receipt and the model/serial number of your
Monessen product.
2. DO NOT ATTEMPT TO DO ANY SERVICE WORK YOURSELF.
40
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
PH Gas Logs
Monessen, a brand of Hearth & Home Technologies
7571 215th Street West, Lakeville, MN 50044
www.monessenhearth.com
Monessen • PH18/24 Installation/Owner's Manual • 65D2035 • Rev E • 01/19
41
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