Thermo Products PGL39-400, PGT11-125, PGT16-160, PGL33-250, PGL20-180 User Manual

INSTALLATION AND SERVICE MANUAL

MODELS:

PGT5-100, PGT11-125, PGT16-160,

PGL20-180, PGL33-250, PGL37-312, & PGL39-400

???? WARNING: IF YOU DO NOT FOLLOW THE SAFETY PRECAUTIONS BELOW AND IN THIS

MANUAL, A FIRE OR EXPLOSION MAY RESULT CAUSING PROPERTY DAMAGE, PERSONAL INJURY,
OR LOSS OF LIFE.

DO NOT STORE OR USE GASOLINE OR OTHER FLAMMABLE 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.

• LEAVE THE BUILDING IMMEDIATELY.

• 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 FIRE DEPARTMENT.

INSTALLATION AND SERVICE MUST BE PERFORMED BY A QUALIFIED INSTALLER, SERVICE
AGENCY OR THE GAS SUPPLIER. (REFERRED TO IN THESE INSTRUCTIONS AS A QUALIFIED
HEATING CONTRACTOR).

PLEASE READ THESE INSTRUCTIONS PRIOR TO INSTALLATION, INITIAL FIRING, AND BEFORE
PERFORMING ANY SERVICE OR MAINTENANCE. THESE INSTRUCTIONS MUST BE LEFT WITH THE
HOMEOWNER AND SHOULD BE RETAINED FOR FUTURE REFERENCE BY QUALIFIED SERVICE
PERSONNEL.

THERMO PRODUCTS,LLC.
BOX 217
NORTH JUDSON, IN 46366

PHONE: [phone]

MG-807C

ECN 4403-MA MADE IN USA

TABLE OF CONTENTS

SECTION

BEGINNING PAGE

WARNING AND INSTRUCTION LABELS 1

WARNINGS AND CAUTIONS 2

I. GENERAL INSTRUCTIONS 3

II. GENERAL INSTALLATION 3
A. CODES AND CLEARANCES 3
B. CONSTRUCTION MATERIALS 3
a. COMBUSTIBLE MATERIALS 3
b. NON-COMBUSTIBLE MATERIALS 3
C. FURNACE LOCATION, COMBUSTION AND MAKE-UP AIR 4
D. VENTING 5
E. VENT DAMPERS 7
F. CONDENSING IN CHIMNEY 7
G. REPLACING AN EXISTING FURNACE FROM A COMMON VENT 8
H. GENERAL GAS PIPING 8
I. INSTALLATION OF NATURAL GAS PIPING 9
J. INSTALLATION OF LP GAS PIPING 10
K. BURNER INSTALLATION 11
L. REQUIREMENTS AND SIZING OF DUCTWORK 15
M. FILTERS 18
a. PGT HORIZONTALS 18
b. PGL LOWBOYS 18
N. FAN AND LIMIT POSITION AND LOCATION 19
O. WIRING 20
III. STARTING THE UNIT 27
A. INITIAL START UP 27
B. BURNER COMBUSTION 27
C. ADJUSTMENT OF BTU INPUT RATE 27
D. FURNACE CHECK OUT PROCEDURE 29
IV. INSTALLER'S INSTRUCTIONS TO USER 29
V. DEALER MAINTENANCE 30
A. ELECTRICAL 30
B. CLEANING HEAT EXCHANGER 30
VI. TROUBLESHOOTING 31
VII. REPLACEMENT PARTS - PGT 32
EPLACEMENT PARTS - PGL 34

All installations and services must be performed by qualified service personnel.

This page contains reproductions of the various warning and instruction labels placed on the Thermo Pride Power Gas
Furnaces. Please read and comply with the contents of these labels.

1

All installations and services must be performed by qualified service personnel.

This page contains various warnings and cautions reproduced from the Power Gas Furnace Manual. Please read
and comply with the statements below

CAUTION: When installing the burner, it should be noted that the loose fill insulation and fiber chambers are made with

ceramic fibers. Currently, there are no known chronic health effects in humans associated with long term exposure to
ceramic fibers. The International Agency for Research on Cancer (IARC) based on its review of studies that injected
ceramic fiber into the abdomens of hamsters and rats have classified fibrous glass wool, mineral wool (both rock wool and
slag wool) and ceramic fiber as group 2B carcinogens. A group 2B agent is considered by IARC to have the possibility of
being carcinogenic to humans. IARC has also classified these fibrous materials as group 2A carcinogens when they have
undergone long term exposure to temperatures greater than 18000F. A group 2A agent is considered to have the probability
of being carcinogenic to humans. For these reasons, we suggest the use of a 3M 9900, 3M 8710 or equivalent mask when
working with any ceramic fiber products. For further information, contact the Manager of Customer Service for Rex Roto
Corporation at [phone].

WARNING:

WARNING:

top opening.

WARNING:

fireplace chimney, lined with a metal liner is used to vent this appliance, the fireplace opening must be permanently sealed.

WARNING:

WARNING:

WARNING:

This should be done by qualified service personnel. If excessive gas escapes when purging the supply at the union, allow the
area to ventilate for at least 15 minutes before attempting to start the furnace. LP gas is especially dangerous because LP gas
is heavier then air allowing it to accumulate at floor level at a dangerous concentration.

WARNING:

WARNING:

WARNING:

transformer. If an electrical vent damper is used, a separate transformer and relay must be installed. Thermally actuated vent
dampers cannot be used with this power burner because the damper must be in the open position before the burner ignites.

WARNING:

below grade, contact your gas supplier for a gas detector.

This furnace is not to be used as a construction heater.

When common venting two appliances into a common vent, the smallest appliances must be vented into the

A Category 1 appliance must never be connected to a chimney that is servicing a solid fuel appliance. If a

The PG Series furnaces must not be installed with a manual or thermally actuated vent damper.

TURN OFF THE ELECTRICAL POWER to the furnace before attempting to change blower speed wiring.

For initial start-up, of the furnace after installation, it may be necessary to purge the air out of the gas line.

Heat exchanger paint will cure on initial firing creating an odor.

The heat exchanger must be cleaned by a qualified service technician.

The power gas burner has its own transformer and no other electrical equipment should be operated from this

Because of the potential of odorant fade, a gas leak may not be detected by smell. If this furnace is installed

.

2

All installations and services must be performed by qualified service personnel.

I. GENERAL INSTRUCTIONS

These instructions must be read in their entirety before installing the furnace. It is the installer's responsibility to do the
following:

1. Inform and demonstrate to the user, the correct operation and maintenance of the appliance.

2. Inform the user of the hazards of flammable liquids and vapors and to remove such liquids and vapors from the vicinity of
the appliance.

II. GENERAL INSTALLATION

These furnaces are shipped with the power gas burner shipped separately. For parts shortage or damage, see the Dealer
Receiving and Freight Claim Procedure Section of the price guide. After installation, the furnace and duct system must be
adjusted to obtain a temperature rise of 50°F to 80°F through the furnace. The installation must conform with local codes or
in the absence of local codes with the National Fuel Gas Codes ANSI Z223.1 LATEST EDITION and to these instructions.

WARNING:

A. CODES AND CLEARANCES:

The following items must be considered when choosing the size and location of the furnace.

1. All local codes and/or regulations take precedence over the instructions in this manual and should be followed
accordingly. In the absence of local codes, installation must conform to these instructions, regulations of the National Fire
Protection Association, provisions of National Electrical Code (ANSI/NFPA70 LATEST EDITION), and the National Fuel
Gas Code (ANSI Z223.1 LATEST EDITION).

2. The BTU output capacity of the furnace proposed for installation should be based on a heat loss calculation made
according to the manuals provided by the Air Conditioning Contractors of America (ACCA) or ASHRAE.

3. The furnace installed is to be level in a central location with respect to outlet registers and should be located near the
chimney to minimize the numbers of elbows and the length of any horizontal run of connecting flue pipe which may be
required.

4. Definitions of "COMBUSTIBLE MATERIAL" and "NON-COMBUSTIBLE" as issued by
NFPA-Z11-1-3 is as follows:

B. CONSTRUCTION MATERIALS

a. COMBUSTIBLE MATERIAL:

Materials made of or surfaced with wood, compressed paper, plant fibers, plastics or other material that will ignite and burn
whether flameproof, fire retardant treated, or plastered.

b. NON-COMBUSTIBLE MATERIAL:

Material which will not ignite and burn; such materials consisting entirely of steel, iron, brick, concrete, slate, glass, plaster
or combination thereof.

This furnace is not to be used as a construction heater.

3

All installations and services must be performed by qualified service personnel.

- MINIMUM CLEARANCES TO COMBUSTIBLE MATERIALS -

MODEL NO. FROM SIDES

OF FURNACE

PGT5-100

PGT11-125

PGT16-160

PGL20-180

PGL33-250

PGL37-312

PGL39-400

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

FRONT TOP & SIDES

OF PLENUM

24 IN.

24 IN.

24 IN.

24 IN.

24 IN.

24 IN.

24 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

FROM THE

FLUE OR

VENT

4 IN.

9 IN.

9 IN.

18 IN.

18 IN.

18 IN.

18 IN.

REAR BOTTOM

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

1 IN.

N/A

N/A

N/A

N/A

The minimum clearances are listed for fire protection. Clearance for servicing the front of the furnaces and to all points on
the furnace requiring access must be 24".

Equipment must be installed in accordance with regulations of the National Board of Fire Underwriters. Authorities
having jurisdiction should be consulted before installations are made.

C. FURNACE LOCATION AND COMBUSTION AIR

A furnace installed in a residential garage must be installed so the burners and ignition source are located higher than 18
inches above the floor. Also, the furnace must be located or protected to avoid physical damage by vehicles. The furnace
must be located on a dry surface. If the surface becomes wet or damp at times, the furnace should be supported above the
floor using a concrete base, bricks, patio blocks, etc.
The electrical components of this furnace should be protected against water or moisture.

The area in which the furnace is located must have an adequate supply of air for combustion and draft. Open non-partitioned
basements, below grade utility room windows without storms or rooms with loose access doors will generally permit
adequate air infiltration. However, if the furnace is located in an area of the building with tight doors and windows, outside
ventilation or an opening into another room is recommended. This can be accomplished with two rectangular openings
located in a wall or door, one 6" from the ceiling or at the top of the door and one 6" from the floor or at the bottom of the
door each having a free area of not less than 1 square inch per 1,000 BTUH input but not less than 100 square inches total.
These openings must be free and unobstructed. Maintain a minimum 24" clearance to ventilation openings, which provide
combustion air to the furnace.

4

All installations and services must be performed by qualified service personnel.

EXAMPLE: 100,000 BTUH input furnaces requires "two" openings of 100 square inches each. A minimum opening of

100 square inches is required regardless of the input.

If the building is tightly constructed and or has an exhaust fan(s) that creates a negative pressure, air for combustion and
ventilation must be supplied from the outdoors or from spaces freely communicating with the outdoors. When
communicating directly with the outdoors or with vertical ducts to the outdoors, two openings each having a minimum free
area of 1 square inch per 4,000 BTU of the input rating of all gas appliances in the area are required. When horizontal ducts
are used to communicate with the outdoors, the free area must be based on 2,000 BTUH per square inch of the total input
rating of all gas appliances in the area. The minimum dimension of an air duct must be at least 4 inches in diameter.
EXAMPLE: 100,000 BTU input furnace, 40,000 BTU input water heater and 30,000 BTU gas dryer would require two
openings of 42.5 square inches each if ducted vertically to the outdoors or 85 square inches each if horizontal ducts are
used.

MAKE-UP AIR

Today's emphasis on home insulation and tightness increases the problem of air supply to the furnace. Heavy insulation cuts
off infiltration of outside air, which previously replaces inside air removed by bathroom, kitchen and laundry vent fans and
air escaping up chimneys. This tightness can cause a negative pressure condition to develop within the home. For this
reason, it is recommended that in tightly constructed and insulated homes, make-up air be provided. This can be done with
Skuttle Mfg. Co. 200 Series make-up air control. This control installs quickly and easily on any warm air heating system and
delivers controlled, fresh air automatically during the winter and summer. This type control helps solve a negative pressure
problem in a structure.

D. VENTING:

NOTICE: A draft control (double acting (MG-1) or hood type) suitable for gas firing, certified by a nationally recognized

testing laboratory and acceptable to local codes must be installed according to the control manufacturer's instructions.

The PGT and PGL series furnaces must be vented in accordance with local codes and the National Fuel Gas Code (ANSI­Z223.1 Latest Edition) Category 1 vent tables.
The vent connector must be galvanized or stainless steel metal pipe.

The following items are requirements:

1. Flue or vent connection materials must meet requirements of all applicable local codes and the National Fuel Gas Code
(ANSI-Z223.1 LATEST EDITION).

2. A PVC pipe is not an acceptable substitute for a chimney or a flue connector. A chimney with an internal construction of
stainless steel or some other material that will withstand the flue gas temperature of 500°F is required.

3. A type B venting system as well as some masonry systems are acceptable as described in the venting tables included in
the NFGC. These venting tables also include venting combinations, which apply to common venting arrangements of two
appliances.

WARNING:

opening.

WARNING:

fireplace chimney, lined with a metal liner is used to vent this appliance, the fireplace opening must be permanently sealed.

4. The chimney height is determined by the height of the surrounding trees, roof, buildings and terrain. The chimney should
extend 24" above any surrounding obstructions.

When common venting two appliances into a common vent, the smallest appliance must be vented into the top

A Category 1 appliance must never be connected to a chimney that is servicing a solid fuel appliance. If a

5

All installations and services must be performed by qualified service personnel.

Trim or remove nearby trees that could interfere with chimney draft.

5. In cases where the chimney flue extends to the basement floor, the draft can usually be improved by filling the base of the
chimney with sand to within 12" of the flue pipe after relocating the cleanout cover.

6. All joints of the vent must be tightly sealed. The inside of the vent should be free of all obstructions.

7. All vents and vent connectors must fit tightly to avoid air leaks.

8. All vent connectors connecting the furnace to the vent must be rigidly supported with hangers and straps, in order to
prevent movement after installation. The vent connector must be supported every four feet for the design and weight of the
material used, to maintain clearances, and to prevent physical damage.

9. Vent connectors used in connecting the furnace to the vent cannot be channeled through floors, ceilings, and walls
without the proper protective construction. This construction must be in accordance with the requirements of the National
Fuel Gas Code (ANSI Z223.1 LATEST EDITION).

10. All single wall vent connectors connected to the PGT & PGL Series furnaces must have all seams and joints sealed with
high temperature pressure sensitive aluminum tape or silicone rubber sealant.

EXAMPLE:

1. High temperature aluminum tape, temperature rating of 400°F or more.

2. Dow Corning RTV-732 rubber sealant or equivalent.
Temperature rating of 450°F or more.

11. Vent connectors installed in or passing through an unheated space must be insulated with 1.0" thick foil faced fiberglass
or its equivalent to prevent condensate from forming in the connector or vent.

6

All installations and services must be performed by qualified service personnel.

NOTE: If this furnace replaces an appliance with a vent that was originally installed in a common vent system serving other

appliances, the vent system is likely now too large to properly vent the remaining appliances only and must be modified
accordingly. Refer to Natural Fuel Gas Code Appendix G Category I vent tables for common venting a PG Series furnace
and another fan assisted or natural draft unit.

In order too common vent a PG Series furnace with a natural draft gas fired hot water heater; follow the recommendation of
the NFGC Category I venting tables.
If the NFGC venting tables do not apply to a specific common venting system then refer to the section on replacing an
existing furnace from a common vent in Section G of this manual.

NOTICE:

for the application and certified by a nationally recognized testing agency for use with gas fired warm air central furnaces.

NOTICE:

also meet the approval of the local authorities. See the draft control manufacturers instructions for installation.

Thermo Pride power gas units may be sidewall vented with a power sidewall venting system that is appropriate

An agency approved gas barometric control or draft diverter must be installed. The draft control device must

E. VENT DAMPERS

If a vent damper is installed, it must be certified by a nationally recognized testing agency. It must be an electro­mechanical type that opens completely before gas flows to the main burner and closes only after the gas valve has
shut off gas flow to the main burner.

WARNING:

F. CONDENSING IN THE CHIMNEY:

Due to the increasing efficiencies of our furnaces, more heat is being placed into the home instead of up the chimney.
This means that the stack temperature will be lowered which may result in condensing within the chimney under
certain conditions. The following is an explanation on why and what to do if condensing occurs.

Moisture occurs in flue gases when hydrogen is mixed with oxygen from the chemical reaction produced by
combustion. This mixture of hydrogen and oxygen produces water molecules.

The flue gas vapor may do one of two things as it escapes up the chimney:

1. Remain in a vapor state if the internal chimney wall temperature is above the dew point, or

2. Condense on the chimney walls if they are chilled below the dew point.

Condensing will always occur on chimney walls whose temperatures are below the dew point, but will evaporate
once the walls are warmer than the dew point. If the chimney walls do not reach the dew point during the cycle of the
furnace, the moisture may accumulate in large enough quantities to cause problems such as corrosion of the chimney
or corrosion of the heat exchanger.

This condensation most likely will not occur at the bottom of the chimney, because the flue gas is heating the
chimney walls as it rises and the bottom will be heated first. This heating of the walls will cause the flue gas
temperature to drop, which in turn may reduce the wall temperature below the dew point causing condensation to
appear on the upper part of the chimney first. This condensation may drip back as far as the flue pipe and heat
exchanger, where corrosion may occur if not treated.

To prevent condensation, it is necessary that the internal chimney wall temperature always be kept above the dew
point. The chimney may have to be lined with a flue liner if the temperature loss is too great for the furnace. A liner
will act as an insulator and reduce the flue gas temperature loss. Insulation may be added around the liner for further

The PG Series furnaces must not be installed with a manual or thermally actuated vent damper.

7

All installations and services must be performed by qualified service personnel.

temperature stability. If the chimney is on the homes exterior and condensing occurs, the chimney may be insulated
around its exterior to help the flue hold its temperature. Also, check to see if the chimney is too large for the flue
gases to heat, if so reduce to proper size by lining. Be sure to use stainless steel liners such as types 430, 304 or for
the toughest corrosion resistant type 316. If the chimney is the correct size for the unit and condensing still occurs
then further insulating of the chimney must occur or the efficiency of the furnace may have to be reduced to raise the
chimney temperature.

More detailed information may be obtained from the current ASHRAE Equipment Handbook.

G. REPLACING AN EXISTING FURNACE FROM A COMMON VENT

When an existing furnace is removed from a common vent serving other appliances, the vent system is likely too
large to safely vent the remaining attached appliances. If only two appliances remain on the venting system, then the
system may be sized with the venting tables in the NFGC of this manual. If more than two appliances remain, then
the following steps shall be followed with each appliance remaining connected to the common venting system placed
in operation, while the other appliances remaining connected to the common venting system are not in operation.

a. Seal off any unused opening(s) in the common venting system.

b. Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion and other deficiencies which could cause an unsafe condition.

c. Insofar as is practical, close all building doors and windows and all doors between the space in which the
appliances remaining connected to the common venting system are located and other spaces of the building. Turn on
clothes dryers and any appliance not connected to the common venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan.
Close fireplace dampers.

d. Follow the lighting instructions. Place the appliance being inspected in operation. Adjust thermostat so appliance
will operate continuously.

e. Test for spillage at the draft hood relief opening after 5 minutes of main burner operation. Use the flame of a
match or candle or smoke from a cigarette, cigar or pipe.

f. After it has been determined that each appliance remaining connected to the common venting system properly
vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other gas­burning appliance to their previous conditions of use.

g. If the improper venting is observed on any of the appliances during the above testing, the common vent system
must be corrected. Follow the steps outlined in the National Fuel Gas Code, NFPA 54/ANSI Z223.1-LATEST
EDITION to resize the vent system. The National Fuel Gas Code may be obtained by writing the American Gas
Association Laboratories, 8501 East Pleasant Valley Road, Cleveland, OH 44131 or the National Fire Protection
Association, Battery march Park, Quincy, MA 02269.

H. GENERAL GAS PIPING

WARNING:

installed below grade, contact your gas supplier for a gas detector.

All gas piping and testing must be performed by a qualified installer or service person. The installation must comply
with local codes, these instructions and The National Fuel Gas Code NFPA54/ANSI Z223.1-LATEST EDITION.

Because of the potential of odorant fade, a gas leak may not be detected by smell. If this furnace is

8

All installations and services must be performed by qualified service personnel.

Piping from the natural gas meter to the furnace shall be in accord with requirements of the local
utility. Piping from the LP tank to the furnace must follow the recommendations of the gas supplier.

1. A readily accessible, certified manual shut off valve with a non-displaceable rotor member should be installed
within six feet of the gas equipment it serves. A union or flanged connection shall be provided downstream from the
manual valve to permit removal of controls. A 1/8" N.P.T. plugged tapping, that is accessible for connecting a test
gage, must be installed immediately upstream of the gas connection to the furnace. Unions must be of a ground joint
type or flanged-joint using a gasket resistant to LPG. Pipe dope or tape certified to be resistant to the action of
liquified petroleum gases should be used on all threaded joints.

2. A drip leg must be used on both LP and natural gas installations prior to the furnace to trap oil, condensate and
other impurities which might otherwise lodge in the gas valve or plug the burner orifice. When there is excessive
condensation between the gas meter and the furnace, a drip leg shall be provided at the outlet of the gas meter.
Failure to install a drip leg may void the limited warranty on the furnace.

NOTE: All gas piping must be leak tested using a soap and water solution (if the gas is turned on) following the
procedure outline in this section (caution must be taken not to wet electronic components). A final test for gas
leakage must be made after purging the gas line. This test must be conducted with the unit operating and should
include the furnace piping and gas valve. Never use an open flame to check for a gas leak.

IMPORTANT: Care must be taken not to wet electronic components during leak test. Wetting the primary ignition
module may damage its circuitry and cause a hazardous situation. If wetting occurs, dry moisture from all leads,
terminals, and electronic components using a hair dryer or similar means or wait at least 24 hours for the circuit to
fully dry before energizing the burner circuit.

The furnace and its individual gas valve must be disconnected from the gas supply during pressure testing of the gas
supply system at pressures in excess of 1/2 PSIG or 14.0" wc.

I. INSTALLATION OF NATURAL GAS PIPING

The installation of the gas piping and the following test procedures must be performed by a qualified installer or
service person.

1. The following chart is to be used as a guide in sizing natural gas supply piping. The input loading of all gas
appliances installed on any main or trunk line must be totaled to determine its needed carrying capacity.

9

All installations and services must be performed by qualified service personnel.

EXAMPLE: A line must supply a furnace of 110,000 BTU/hr input, a hot water heater of 40,000 BTU/hr input and

gas range with a 30,000 BTU/hr input capacity. The total BTU/hr input loading on the line is 180,000 BTU/hr. The
200,000 BTU/hr column on the chart must be used in sizing the pipe.

┌─────────────┬────────────────────────────────────────────────┐
│BURNER FIRING│ FEET OF PIPE FROM METER TO BURNER │
│RATE, BTU/HR │10' 20' 30' 40' 50' │
├─────────────┼─────────┬─────────┬─────────┬─────────┬────────┤
│50,000 │1/2 │1/2 │3/4 │3/4 │3/4 │
├─────────────┼─────────┼─────────┼─────────┼─────────┼────────┤
│100,000 │3/4 │3/4 │3/4 │3/4 │1 │
├─────────────┼─────────┼─────────┼─────────┼─────────┼────────┤
│150,000 │3/4 │1 │1 │1 │1-1/4 │
├─────────────┼─────────┼─────────┼─────────┼─────────┼────────┤
│200,000 │1 │1 │1-1/4 │1-1/4 │1-1/4 │
├─────────────┼─────────┼─────────┼─────────┼─────────┼────────┤
│250,000 │1 │1 │1-1/4 │1-1/4 │1-1/4 │
├─────────────┼─────────┼─────────┼─────────┼─────────┼────────┤
│300,000 │1 │1 │1-1/4 │1-1/4 │1-1/4 │
└─────────────┴─────────┴─────────┴─────────┴─────────┴────────┘

Use black iron steel pipe and malleable iron fittings for Natural gas service lines. Provide rigid supports for the pipe.
If the pipe size must be reduced, use reducing couplings only. Avoid the use of reducing bushings. Remove all burrs
and inspect the pipe for dirt or other foreign material prior to connecting.

Maximum supply pressure for natural gas is 14" wc and minimum supply for purpose of input adjustment is 5-1/2"
wc.

J. INSTALLATION OF LIQUIFIED PETROLEUM GAS (LP) PIPING

1. Experience has proved that the pressure drop in the gas line running from the outside propane gas tank to the gas
appliances in a home, is the most frequent cause of equipment malfunctions. A single pressure regulator, located at
the tank, will not reliably regulate the high tank pressures (up to 200 lbs.) down to 11" wc. Varying pressures will
occur at the appliances as outside temperatures and usage demands vary. Two stage regulations are the only effective
method of controlling these variables.

- BLACK PIPE SIZE FOR NATURAL GAS -

TYPICAL PIPING FOR TWO STAGE REGULATION

NOTE: Two stage regulation must be installed for liquified petroleum gas when used with any Thermo Pride LP

furnace. See illustration above of a typical two stage piping system.

10