Munchkin HIGH EFFICIENCY HEATER with the ""925"" Controller, MUNCHKIN Operating Instructions Manual
HEAT TRANSFER PRODUCTS, INC.
120 BRALEY RD., E. FREETOWN, MA 02717
Installing, Operating & Maintaining
MUNCHKIN™ HIGH EFFICIENCY HEATER
with the “925” Controller
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.
• 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.
WARNING
If the information in this manual is not followed exactly, a fire or explosion may
result causing property damage, personal injury or loss of life.
WARNING
This manual must only be used by a qualified heating installer / service
technician. Failure to comply could result in severe personal injury, death or
substantial property damage. It is also important to keep these Instructions
with the appliance.
MH27745
CONTROLS
USING THIS MANUAL
2
SPECIAL ATTENTION BOXES
Throughout this manual you will see these
special attention boxes similar to this one,
which are intended to supplement the
instructions and make special notice of
potential hazards. These categories mean, in
the judgement of Heat Transfer Products, Inc.:
NOTICE
Heat Transfer Products manufactures both
ASME and Non-ASME boilers. It is the
responsibility of the installer that the correct
model has been selected for jurisdiction
requirements.
WARNINGS
• THIS UNIT IS FOR CATEGORY IV VENTING - 2 PIPE ONLY. THIS IS A SEALED
COMBUSTION APPLIANCE.
• THIS HEATER INSTALLATION MUST CONFORM TO THE LATEST EDITION OF THE
“NATIONAL FUEL GAS CODE” ANSI Z223.1 NFPA 54 AND OR CAN/CGA B149
INSTALLATION CODES. STATE AND LOCAL CODES MIGHT ALSO APPLY TO
INSTALLATION.
• WHERE REQUIRED BY THE AUTHORITY HAVING JURISDICTION, THE
INSTALLATION MUST CONFORM TO THE STANDARDS FOR CONTROLS AND
SAFETY DEVICES FOR AUTOMATICALLY FIRED HEATERS, ANSI/ASME HEATER
AND PRESSURE VESSEL CODE, Section IV, ALONG WITH CSD1.
• THE HEATER, GAS PIPING, WATER PIPING, VENTING AND ELECTRICAL MUST BE
INSTALLED BY TRAINED & QUALIFIED PERSONNEL FAMILIAR WITH
INSTALLATION PRACTICES, LOCAL CODE, LICENSING REQUIREMENTS.
• IF THE INFORMATION IN THESE INSTRUCTIONS ARE NOT FOLLOWED EXACTLY,
A FIRE OR EXPLOSION MAY RESULT; CAUSING PROPERTY DAMAGE, PERSONAL
INJURY, OR DEATH.
• DO NOT STORE OR USE GASOLINE OR OTHER FLAMMABLE VAPORS AND
LIQUIDS IN THE VICINITY OF THIS OR ANY OTHER APPLIANCE;
• THE USE OF A LOW WATER CUT-OFF DEVICE MAY BE REQUIRED BY STATE OR
LOCAL CODES IF THE MUNCHKIN IS INSTALLED ABOVE RADIATION LEVELS.
USING THIS MANUAL
DANGER
DANGER indicates an imminently hazardous
situation which, if not avoided, will result in
death or serious injury.
WARNING
WARNING indicates a potentially hazardous
situation which, if not avoided, could result in
death or serious injury.
CAUTION
CAUTION Indicates a potentially hazardous
situtation which, if not avoided, may result in
minor or moderate injury.
CAUTION
CAUTION used without the safety alert symbol
indicates a potentially hazardous situation which,
if not avoided, may result in property damage.
TABLE OF CONTENTS
3
TABLE OF CONTENTS
PART 1 . . . . . . . . . . . . . . . . . . . . . .4 thru 8
GENERAL INFORMATION
A How It Operates . . . . . . . . . . . . . . . . . .4
B Munchkin Ratings and Dimensions . . .4
C Pre-installation Requirements . . . . . . .8
D Pressure Relief Valve . . . . . . . . . . . . . .9
PART 2 . . . . . . . . . . . . . . . . . . . . .9 thru 11
ELECTRICAL
A Electrical Connection . . . . . . . . . . . . . .9
PART 3 . . . . . . . . . . . . . . . . . . . .12 thru 13
GAS CONNECTION
A Gas Connection . . . . . . . . . . . . . . . . . .12
B Gas Piping . . . . . . . . . . . . . . . . . . . . . .12
C Gas Table . . . . . . . . . . . . . . . . . . . . . . .12
PART 4 . . . . . . . . . . . . . . . . . . . .14 thru 21
VENTING
A Approved Venting Materials . . . . . . . .14
B Venting the Munchkin . . . . . . . . . . . . .15
C Longer Vent Runs . . . . . . . . . . . . . . . .17
D Heater Removal from a
Common Vent System . . . . . . . . . . . .18
E Condensate Removal . . . . . . . . . . . . .18
PART 5 . . . . . . . . . . . . . . . . . . . .22 thru 33
PIPING
A Hydronic piping with
Circulators or Zone Valves . . . . . . . . .22
B Circulator Sizing . . . . . . . . . . . . . . . . .23
C Fill and Purge Heating System . . . . . .24
D Piping Illustrations . . . . . . . . . . . . . . .25
PART 6 . . . . . . . . . . . . . . . . . . . .34 thru 37
START UP PROCEDURES
A Sequence of operation . . . . . . . . . . . .34
B Items to be checked before
lighting the Munchkin . . . . . . . . . . . . .34
C Lighting Instructions . . . . . . . . . . . . . .35
D Operating Instructions . . . . . . . . . . . .35
E Adjusting the Temperature
on the Munchkin Display . . . . . . . . . .36
F Status Menu . . . . . . . . . . . . . . . . . . . .36
G Test Mode . . . . . . . . . . . . . . . . . . . . . .37
H To Turn Off Gas to Appliance . . . . . . .37
PART 7 . . . . . . . . . . . . . . . . . . . .38 thru 40
TROUBLESHOOTING
A Munchkin Error Code . . . . . . . . . . . . .38
B Boiler Error . . . . . . . . . . . . . . . . . . . . .38
C Boiler Fault . . . . . . . . . . . . . . . . . . . . .38
PART 8 . . . . . . . . . . . . . . . . . . . .40 thru 44
MAINTENANCE
A Maintenance Procedures . . . . . . . . . .41
B Before Each Heating Season . . . . . . .41
C Condensate Cleaning Instructions . . .41
D Combustion Chamber
Coil Cleaning Instructions . . . . . . . . . .42
E Munchkin Controller . . . . . . . . . . . . . .43
F Components Diagrams . . . . . . . . .44–45
GENERAL INFORMATION
4
B. MUNCHKIN RATINGS AND DIMENSIONS
PERFORMANCE RATINGS
*Net water
CONNECTION SIZES
PART 1. GENERAL INFORMATION
A. HOW IT OPERATES
When the room thermostat calls for heat, the Munchkin control board will start the circulator and start
to monitor the return temperature of the system before the heater will begin to heat the water. Once
the controller has sensed a drop in the return water temperature below the temperature set point
minus the differential set point, the heater will start to heat the water. This eliminates the Munchkin
starting every time the thermostat calls for heat. This feature keeps the system from short cycling.
Once the system has sensed the temperature difference, the Munchkin will activate the blower motor
for 5 seconds to pre-purge the system before starting the Munchkin
. The Munchkin controller will now
start to modulate the pre-mix burner based on analyzing the return temperature, supply water
temperature and the set point temperature. By compiling this information, the controller utilizes an
algorithm to fully adjust the firing rate while maintaining the desired output temperature. The pre-mix
burner fan has a direct drive current low-voltage motor with a pulse relay counting. This system allows
precise control over the fan speed and combustion air volumes. Coupled with the Honeywell gas valve
and the Venturi system which are set to provide a one-to-one ratio of precisely measured volumes of
fuel to air, an accurate and instant burner output is achieved. This keeps the Munchkin running at the
highest efficiency.
When the thermostat is satisfied, the Munchkin will then go through a 4 second post-purge cycle before
shutting off. Every Munchkin heater is equipped with a display which will read the outlet temperature of
the heater and then will illuminate a green light showing flame on. If a problem occurs, the front indicator
light will turn red and the display will read a fault code; see Part 7, Section B/C.
B. MUNCHKIN RATINGS AND DIMENSIONS
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M05T000,05ot000,81000,64ot000,61%29.sbl85000,04
M08T000,08ot000,91000,47ot000,71%29.sbl85000,46
M08000,08ot000,72000,47ot000,52%29.sbl57000,46
M041000,041ot000,64000,921ot000,34%29.sbl101000,211
M991000,991ot000,66000,381ot000,16%29.sbl111000,951
ledoM
M05TTPN"4/11"4/3"2
M08TTPN"4/11"4/3"2
M08TPN"4/11"4/3"3
M041TPN"4/11"4/3"3
M991TPN"4/11"4/3"3
nruteR/ylppuS
noitcennoCeziSnoitcennoCsaG.aiDtneV
GENERAL INFORMATION
5
Figure 1-1
(NOTE: The Munchkin is rated at
zero clearance to combustibles.)
80M/140M/199M
T50M/T80M
RECOMMENDED SERVICE CLEARANCES
Figure 1-2
GENERAL INFORMATION
6
Figure 1-3
T50M/T80M
DIMENSIONS
GENERAL INFORMATION
7
DIMENSIONS
80M
140M/199M
Figure 1-4
Figure 1-5
GENERAL INFORMATION
8
C. PRE-INSTALLATION REQUIREMENT
GENERAL
1. Munchkin Boilers are supplied completely assembled as packaged boilers. The
package should be inspected for damage
upon receipt and any damage to the unit
should be reported to the shipping company and wholesaler. This boiler should
be stored in a clean, dry area.
2. Carefully read these instructions and be
sure to understand the function of all
connections prior to beginning installation. Contact your Munchkin Sales
Representative or the Heat Transfer
Products, Inc. Customer Service
Department for help in answering questions.
3. This boiler must be installed by a qualified contractor. The boiler warranty may
be voided if the boiler is not installed correctly.
CODES & REGULATIONS
Installation and repairs are to be performed in
strict accordance with the requirements of state
and local regulating agencies and codes dealing
with boiler and gas appliance installation.
ACCESSIBILITY CLEARANCES
1. The Munchkin Boiler is certified for closet installations with zero clearance to
combustible construction. In addition, it
is design certified for use on combustible
floors.
2. Refer to Figure 1.1 and Figure 1.2 for the
recommended clearance to allow for reasonable access to the boiler. Local codes
or special conditions may require greater
clearances.
COMBUSTION AND VENTILATION AIR
1. The Munchkin Boiler is designed only for
operation with combustion air piped
from outside (sealed combustion). PVC
pipe must be supplied between the air
inlet connection at the rear of the boiler
through an outside wall.
2. No additional combustion or ventilation
air is required for this appliance.
3. Refer to Section 4 of this manual,
Venting, for specific instructions for piping combustion air.
PLANNING THE LAYOUT
1. Prepare sketches and notes showing the
layout of the boiler installation to minimize the possibility of interferences with
new or existing equipment, piping, venting and wiring.
2. The following sections of this manual
should be reviewed for consideration of
limitations with respect to:
a. Electrical Wiring: Part 2
b. Gas Connection: Part 3
c. Venting: Part 4
f. Piping: Part 5
WARNING
Liquefied Petroleum (LP) Gas or
Propane is heavier than air and, in the
event of a leak, may collect in low
areas such as basements or floor
drains. The gas may then ignite
resulting in a fire or explosion.
CAUTION
Do not install this boiler on carpeting.
GENERAL INFORMATION / ELECTRICAL
9
Note: Service clearance of the Munchkin: See Section 1, Figures 1-1 and 1-2.
If the Munchkin is set up for liquefied petroleum (LP) gas, some geographic areas follow the Uniform
Mechanical Code, section 304.6, “Liquefied petroleum gas burning appliances shall not be installed in
a pit, basement or similar location where heavier-than-air gas might collect. Appliances so fueled, shall
not be installed in a below grade under-floor space or basement unless such location is provided with
an approved means for removal of unburned gas.”
PART 2. ELECTRICAL
A. ELECTRICAL CONNECTION
The electrical connection for the Munchkin is on the left hand side of the unit. There is a ½” knockout
location for an electrical connection for both the incoming power and the central heating circulator
connection. All electrical wiring must be performed by a qualified licensed electrician in accordance
with National Electrical Code ANSI Z223.1//NFPA 54 to and/or the Canadian Electrical Code, Part 1 CSA
C22.1, or to the applicable codes and standards. For your convenience, we have labeled all the wires
that need to be connected to operate the Munchkin.
CAUTION
The Munchkin is certified as an indoor appliance. Do not install the Munchkin
outdoors or locate where it will be exposed to freezing temperature. This includes all
related piping and components. If the Munchkin is subjected to flood water or
submersed in water, the Munchkin must be replaced.
CAUTION
Condensation removal: This is a condensing high efficiency appliance, therefore
condensation removal must be addressed to avoid damage to surrounding area or
appliance. See Part (4) Section E for Condensate Requirements.
WARNING
D. PRESSURE RELIEF VALVE
A pressure relief valve is installed into the front right side manifold. We recommend a WATTS ¾"
M 335 MI valve or equivalent and meets the requirements of ANSI/ASME Heater and Pressure
Vessel Code, Section IV or CSA B51; Heater, Pressure Vessel and Piping Code as applicable for
heating heaters. A ¾" pipe must be directed to a floor drain or suitable location within 6" of a drain
or floor. Protect from freezing, do not plug or cap pressure relief valve. Serious explosion causing
property damage and or loss of life could result. Under no circumstances should the relief valve
be eliminated, capped or plugged.
10
ELECTRICAL
The electrical requirements are for standard 120 volts, 60 Hz 15 Amp service. This unit is wired with
#18 awg and fused for no more than 15 Amps.
There are two ground points in the electrical compartment that must be connected to the building
ground system. Connect the building ground to the green ground screw and the green ground wire
inside electrical box provided.
The Incoming Power Supply is connected to the Black (Hot) and the White (Neutral).The Munchkin
Control board is polarity sensitive. If the polarity is reversed, the Munchkin control will not sense a
flame and lock out the system. The Orange and Brown wire are provided to the supply of 120 volts to
the Central Heating Circulator. Connect the Orange (Hot) and the Brown (Neutral) directly to the Central
Heating Circulator.
Connect the gray wires to your heating thermostat (TT) connection. Your thermostat heat anticipator
setting is .056 amp.
It is important that the electrical power is not turned on at this time. Double check all connections and then
turn the power on. The display that is provided with the Munchkin should now be reading the outlet
temperature. Note: see Part 6/Startup Procedure section in the manual to change the temperature setting
or run the heater.
CAUTION
Electrical wiring on the Incoming Power and Central Heating Circulator shall be
connected directly to the intended connection source and not be connected together
inside the electric box provided. An Electrical Short will result and the Control board
will have to be replaced! If Electrical Requirements of the Central Heating Circulator
exceeds 4 amps (or 3 amps on HA models only) please follow the wiring diagrams on
Figures 2-1, 2-2 and 2-3 (this section).
DANGER
IT IS EXTREMELY IMPORTANT THAT THIS UNIT BE PROPERLY GROUNDED!
DANGER
IT IS VERY IMPORTANT THAT THE BUILDING GROUND IS INSPECTED BY A
QUALIFIED ELECTRICIAN PRIOR TO MAKING THIS CONNECTION!
DANGER
The Orange wire for the Central Heating Circulator is Switched Hot and must have a
wire nut if not connected to the Central Heating Circulator. Failure to follow this
instruction will result in a short, and the Control Board will have to be replaced.
CAUTION
Do not power zone valves directly from the heater transformer. Doing so will greatly
reduce the life of the transformer. Use a separate transformer sized to handle the total
electric load of all zone valves.
11
ELECTRICAL
Figure 2-1: Connection Wiring Directly to
Central Heating Circulator
Figure 2-2: Connection Wiring without Wiring
Central Heating Circulator
Note to Electrical Contractor: The orange
wire is 120 Volt/4 Amp maximum for central
heating circulator only. Loads greater than 4
amps or 3 amps for HA models only will blow the
fuse on the board. The brown wire is the neutral wire for the central heating pump only.
Figure 2-3: For circulator amp loads greater
than 4 amps (3 amps for “HA” models) use the
wiring diagram shown at left. The brown and
orange wires will not be used in this
application.
5
T
1
2
3
6
4
T
1K1 1K2
BOILER
"TT"
GRAY
ZONE
CIRCULATOR
120 VOLT
L1 HOT (BLACK)
GRAY
BOILER
"TT"
THERMOSTAT
ZONE
R845A
SWITCHING
RELAY ZONE
1K1
L2 NEUTRAL
(WHITE)
DIAGRAM "A"
WIRING DIAGRAM CONNECTING TO CIRCULATOR
GREEN (GROUND)
WHITE (NEUTRAL)
BLACK
NORMALLY OPEN
THERMOSTAT
CONNECTION
GRAY
T
GRAY
T
BROWN (NEUTRAL)
ORANGE (HOT)
GREEN (GROUND)
ELECTRICAL
SWITCH JUNCTION BOX
120V 60 HZ
WHITE
(NEUTRAL)
BLACK
(HOT)
GREEN
(GROUND)
DIAGRAM "B"
WIRING DIAGRAM WITHOUT CONNECTION TO CIRCULATOR
IMPORTANT NOTE:
BE CERTAIN THAT THE ORANGE
WIRE IS SECURELY CAPED.
GREEN
FAILURE TO DO SO COULD
RESULT IN INJURY OR FIRE
AND COULD DAMAGE THE CONTROL.
WHITE
(NEUTRAL)
GREEN (GROUND)
GREEN
(GROUND)
ELECTRICAL
BLACK
(HOT)
GROUND
BUS
NORMALLY OPEN
THERMOSTAT
CONNECTION
GRAY
T
GRAY
T
BROWN
ORANGE
ORANGE (HOT)
BROWN (NEUTRAL)
SWITCH JUNCTION BOX
120V 60 HZ
12
GAS CONNECTION
PART 3. GAS CONNECTION
A. GAS CONNECTION
The gas supply shall have a maximum inlet pressure of less
than 14" water column (350 mm), ½ pound pressure (3.5 kPa),
and a minimum of 3.5" water column. The entire piping
system, gas meter and regulator must be sized properly to
prevent pressure drop greater than 0.5" as stated in the National
Fuel Gas Code. This information is listed on the rating plate. It is
very important that you are connected to the type of gas as noted on
the rating plate. "LP" for liquefied petroleum, propane gas or, "Nat"
natural or city gas. All gas connections must be approved by the local gas supplier, or utility in addition
to the governing authority, prior to turning the gas supply on. The nipple provided is ½" and it is
mandatory that a ¾" to ½" reducing coupling (provided) is used, threaded into the branch of a ¾" tee,
and a drip leg fabricated, as per the National Fuel Gas code. You must ensure that the entire gas line
to the connection at the Munchkin is no smaller than ¾". Once all the inspections have been
performed, the piping must be leak tested. If the leak test requirement is a higher test pressure than
the maximum inlet pressure, you must isolate the Munchkin from the gas line. In order to do this, you
must shut the gas off using factory and field-installed gas cocks (following the lighting instructions in
Part 6 Section B.) This will prevent high pressure. Failure to do so may damage the gas valve. In the
event the gas valve is exposed to a pressure greater than ½ PSI, 14" water column, the gas valve must
be replaced. Never use an open flame (match, lighter, etc.) to check gas connections.
B. GAS PIPING
1. Run the gas supply line in accordance with all applicable codes.
2. Locate and install manual shutoff valves in accordance with state and local requirements.
C. GAS TABLE
Refer to Table (1) to size the supply piping to minimize pressure drop between meter or regulator
and unit.
Maximum Capacity of Pipe in Cubic Feet of Gas per Hour for Gas Pressures of 0.5 psi or Less and a
Pressure Drop of 0.3 Inch water Column
(TABLE 1) (Based on a 0.60 Specific Gravity Gas)
Nominal
Iron Pipe Internal Length of Pipe (Feet)
Size Diameter
(inches) (inches) 10 20 30 40 50 60 70 80 90 100 125 150 175 200.
3/4 .824 278 190 152 130 115 105 96 90 84 79 72 64 59 55} BTU'S
1 1.049 520 350 285 245 215 195 180 170 160 150 130 120 110 100} PER
1 1/4 1.380 1,050 730 590 500 440 400 370 350 320 305 275 250 225 210} HOUR
1 1/2 1.610 1,600 1,100 890 760 670 610 560 530 490 460 410 380 350 320} X 1,000
WARNING
Failure to follow all precautions could result in fire, explosion or death!
13
WARNING
Failure to follow all precautions could result in fire, explosion or death!
GAS CONNECTION
It is recommended that a soapy solution be used to detect leaks. Bubbles will appear on the pipe to
indicate a leak is present. The gas piping must be sized for the proper flow and length of pipe, to avoid
pressure drop. Both the gas meter and the gas regulator must be properly sized for the total gas load.
If you experience a pressure drop greater than 1" WC, the meter, regulator or gas line is undersized or
in need of service. You can attach a manometer to the incoming gas drip leg, by removing the cap and
installing the manometer. The gas pressure must remain between 3.5" and 14" during stand-by (static)
mode and while in operating (dynamic) mode. If an in-line regulator is used, it must be a minimum
of 10 feet from the Munchkin. It is very important that the gas line is properly purged by the gas
supplier or utility. Failure to properly purge the lines or improper line sizing, will result in ignition
failure. This problem is especially noticeable in NEW LP installations and also in empty tank situations.
This can also occur when a utility company shuts off service to an area to provide maintenance to their
lines. This gas valve must not be replaced with a conventional gas valve under any circumstances. As
an additional safety feature, this gas valve has a flanged connection to the Venturi and blower.
DUNGS GAS VALVE
THROTTLE ADJUSTER
(NOTE: IF FOR ANY
REASON THE THROTTLE
NEEDS TO BE
ADJUSTED, IT IS
VERY IMPORTANT THAT
A "COMBUSTION
ANAYLYZER" BE USED
TO ENSURE SAFE AND
PROPER OPERATION.
TURN THE ADJUSTER
TO THE (+) TO
INCREASE GAS OR THE
(-) TO DECREASE THE
GAS SUPPLY. THIS
ADJUSTMENT COULD
AFFECT CO/CO%
LEVELS. MAKE SURE
THE LEVELS
CORRESPOND TO THE
CHART IN COMBUSTION
SETTINGS.)
Fig. 3-1
14
VENTING
PART 4. VENTING
A. APPROVED VENTING MATERIALS
Exhaust V
ent and Extensions
in Plastic 2", 3" and 4" Pipe Schedule 40 or 80.
1. Non Foam Core PVC Pipe
2. Non Foam Core CPVC Pipe
3. Non Foam Core ABS Pipe
Vent Piping must conform to following
1. PVC Non Foam Core Pipe (Polyvinyl Chloride) to ASTM D-1785 or D-1784 Class 12454-B,
Formerly designated Type 1, Grade 1.
2. CPVC (Chlorinated Polyvinyl Chloride) Class 23447-B, Formerly designated Type IV, Grade 1 conforming to ASTM D-1784.
3. ABS (Acrylonitrile-Butadiene-Styrene) Class 3-2-2-2-2 conforming to ASTM D3965.
The Munchkin is a direct vent appliance. The Munchkin is listed as a Category
IV Condensing Appliance. (The Munchkin Venting is rated at Zero Clearance
to combustibles.)
Note: For Concrete construction or to meet certain fire codes, exhaust and inlet piping at the wall
penetration to the Munchkin must be CPVC Schedule 40 or 80 to meet local fire codes. The balance
from the penetrated wall to the outside, may be PVC Schedule 40 or 80.
Inlet Air V
ent
Use the same material as used for exhaust in either 2", 3" or 4" Plastic Pipe. Cellular Foam Core Pipe
may be used for the inlet only, NEVER ON EXHAUST PIPING!
DANGER
It is extremely important to follow these venting instructions carefully. Failure to do
so can cause severe personal injury, death or substantial property damage.
DANGER
Foam Core Pipe is not to be used in connecting the exhaust pipe.
WARNING
This vent system will operate with a positive pressure in the vent pipe. Do not
connect vent connectors serving appliances by natural draft into any portion of
mechanical draft systems operating under positive pressure.
15
VENTING
B. VENTING THE MUNCHKIN
The inlet pipe on the back of the cabinet should be 3" PVC schedule 40. It is very important that you
plan the location properly to eliminate long pipe runs and excessive fittings. Inlet pipe size must not
be reduced. Do not combine the inlet air with any other inlet pipe including an inlet to an additional
similar appliance. The joints must be properly cleaned, primed and cemented. The piping must also
be properly supported as per Local and National Standard Plumbing Codes. It is important that the
piping must be clean and free from burrs, debris, ragged ends and particles of PVC.
Exhaust piping should be sloped back to the connection on the Munchkin, at least ¼" per foot to
remove additional condensate that forms within the pipe. The total combined length of pipe (intake
piping plus exhaust piping added together) including elbow allowances intake and exhaust (each
elbow = 5' of pipe) should not exceed 85'. The combined vent length should not be less than a combined length of 6' plus two 90 degree elbows. Choose your vent termination locations carefully. You
must also make certain that exhaust gas does not re-circulate back into the intake pipe. You must
place them in an open area and follow the following guidelines.
1) Never vent into a walkway, patio area, alley or otherwise public area less than 7' from the
ground. (See the following detail references Fig. A.10.8 in the National Fuel Gas Code 2002
“Exit Terminals of Mechanical Draft and Direct-Venting Systems”.)
2) Never vent over or under a window or over a doorway where the exhaust plume or condensation liquid will cause obtrusive or dangerous conditions. (Or refer to National Fuel Gas
Code, CAN B149)
3) Never install a heat saver or similar product to capture waste heat from exhaust.
4) Always have a vent location at least 1' above maximum snow level.
5) Always have vent 1' above ground level, away from shrubs and bushes.
6) Follow local gas codes in your region or refer to National Fuel Gas Code, Can B149.
7) Always have at least 3' from an inside corner of outside walls.
8) Maintain at least 4' clearance to electric, gas meters, windows, exhaust fans, chimneys, inlets
or mechanical vents.
9) Very Important! The inlet air connection must be connected to outside air and should be
located no closer than 8" to the exhaust and no further than 36".
10) Always place screens in all openings in intake and exhaust to prevent foreign matter from
entering the Munchkin.
11) The vent intake and exhaust must be properly cleaned and glued for a pressure tight joint.
Several methods for venting the Munchkin can be found in Figures 4-1 thru 4-6 in this section.
Use these layouts as guidelines: certain site conditions such as multiple roof lines/pitches
DANGER
It is extremely important to follow these venting instructions exactly. Failure to do so
can cause severe personal injury, death or substantial property damage.
CAUTION
The following are code restrictions for the location of the flue gas vent terminal.
Compliance to these requirements doesn’t insure a satisfactory installation; good
common sense must also be applied. It is important to make sure that exhaust gases
are not recirculated into the inlet air of the Munchkin.
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