Munchkin VWH High Efficiency Hot Water Supply Boiler Manual

HEAT TRANSFER PRODUCTS, INC.
120 BRALEY RD., E. FREETOWN, MA 02717
Installing, Operating & Maintaining
MUNCHKIN VWH HIGH EFFICIENCY
HOT WATER SUPPLY BOILER
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
USING THIS MANUAL
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.:
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.
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 NEPA 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.

TABLE OF CONTENTS
3
TABLE OF CONTENTS
PART 1 . . . . . . . . . . . . . . . . . . . . . .4 thru 8
GENERAL INFORMATION
AHow It Operates . . . . . . . . . . . . . . . . . .4
BMunchkin Ratings and Dimensions . .5–7
CPre-installation Requirements . . . . . . .7
DPressure Relief Valve . . . . . . . . . . . . . .8
PART 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
ELECTRICAL
AElectrical Connection . . . . . . . . . . . . . .9
PART 3 . . . . . . . . . . . . . . . . . . . .10 thru 11
GAS CONNECTION
AGas Connection . . . . . . . . . . . . . . . . . .10
BGas Piping . . . . . . . . . . . . . . . . . . . . . .10
CGas Table . . . . . . . . . . . . . . . . . . . . . . .10
PART 4 . . . . . . . . . . . . . . . . . . . .12 thru 18
VENTING
AApproved Venting Materials . . . . . . . .12
BVenting the Munchkin in
3”, 4” or 6” Plastic Pipe . . . . . . . . . . .12
CLonger Vent Runs . . . . . . . . . . . . . . .14
DHeater Removal from a
Common Vent System . . . . . . . . . . . .15
ECondensate Removal . . . . . . . . . . . . .16
PART 5 . . . . . . . . . . . . . . . . . . . .19 thru 29
PIPING
AExpansion Tank . . . . . . . . . . . . . . . . . .19
BHigh Velocity Circulator Pump . . . . . .19
PART 6 . . . . . . . . . . . . . . . . . . . .29 thru 33
START UP PROCEDURES
ASequence of Operation . . . . . . . . . . .29
BItems to be checked before
lighting the Munchkin . . . . . . . . . . . . .29
CLighting Instructions . . . . . . . . . . . . . .30
DOperating Instructions . . . . . . . . . . . .30
EAdjusting the Operating Set Points
of the Munchkin VWH Display . . . . . .30
FStatus Menu . . . . . . . . . . . . . . . . . . . .31
GTest Mode . . . . . . . . . . . . . . . . . . . . . .31
HTo Turn Off Gas to Appliance . . . . . . .32
PART 7 . . . . . . . . . . . . . . . . . . . .34 thru 36
TROUBLESHOOTING
AMunchkin Error Code . . . . . . . . . . . . .34
BBoiler Error . . . . . . . . . . . . . . . . . . . . .34
CBoiler Fault . . . . . . . . . . . . . . . . . . . . .34
PART 8 . . . . . . . . . . . . . . . . . . . .37 thru 41
MAINTENANCE
AMaintenance Procedures . . . . . . . . . .37
BAnnual Maintenance . . . . . . . . . . . . . .37
CCondensate Cleaning Instructions . . .37
DCombustion Chamber
Coil Cleaning Instructions . . . . . . . . . .38
EMunchkin Controllers . . . . . . . . . . . . .39

GENERAL INFORMATION
4
RECOMMENDED SERVICE CLEARANCES
PART 1. GENERAL INFORMATION
A. HOW IT OPERATES
The Munchkin VWH is a hot water supply boiler designed to operate in conjuction with a hot water
storage tank. Each Munchkin VWH is equipped with a high velocity pump to keep the unit running
efficiently for many years of service. A flow switch monitors the water flow through the heat exchanger
to make sure that the unit has an adequate flow rate during operation. The Munchkin VWH Controller
accurately monitors the return and supply temperature that controls the output range of the Munchkin
When the system has sensed a temperature drop below the set point and minus the differential set
point, The Munchkin VWH will activate the blower motor for a pre-purge of 5 seconds before going
into operation. Once in operation, the Munchkin controller will now start to modulate the pre-mix
burner based on analyzing the return, supply, differential and operating set point temperatures. 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 direct drive current, low-
voltage motor with pulse relay counting. This system allows precise control over the fan speed and
combustion air volumes. Coupled with the fuel and air mixing 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 VWH running at the highest efficiency.
RECOMMENDED SERVICE CLEARANCES
Figure 1-1

GENERAL INFORMATION
5
B. MUNCHKIN RATINGS AND DIMENSIONS
MODEL INLET OUTLET RECOVERY RATE FIRST HOUR RATING
W/ 80 GAL. STORAGE TANK
FIRST HOUR RATING
W/ 119 GAL. STORAGE TANK
199 VWH 40° 80° 561 GAL 614 GAL 640 GAL
199 VWH 40° 90° 450 GAL 503 GAL 529 GAL
199 VWH 40° 100° 374 GAL 427 GAL 453 GAL
199 VWH 40° 110° 320 GAL 373 GAL 399 GAL
199 VWH 40° 120° 280 GAL 333 GAL 359 GAL
199 VWH 40° 130° 250 GAL 303 GAL 329 GAL
199 VWH 40° 140° 224 GAL 277 GAL 303 GAL
199 VWH 40° 150° 205 GAL 258 GAL 284 GAL
199 VWH 40° 160° 188 GAL 241 GAL 267 GAL
199 VWH 40° 170° 173 GAL 226 GAL 252 GAL
199 VWH 40° 180° 160 GAL 213 GAL 239 GAL
399 VWH 40° 80° 1125 GPH 1178 GAL 1204 GAL
399 VWH 40° 90° 900 GPH 953 GAL 979 GAL
399 VWH 40° 100° 750 GPH 803 GAL 829 GAL
399 VWH 40° 110° 642 GPH 695 GAL 721 GAL
399 VWH 40° 120° 562 GPH 615 GAL 641 GAL
399 VWH 40° 130° 500 GPH 553 GAL 579 GAL
399 VWH 40° 140° 450 GPH 503 GAL 529 GAL
399 VWH 40° 150° 409 GPH 462 GAL 488 GAL
399 VWH 40° 160° 375 GPH 428 GAL 454 GAL
399 VWH 40° 170° 346 GPH 399 GAL 425 GAL
399 VWH 40° 180° 321 GPH 374 GAL 400 GAL
Model Input
Modulation
Output
Modulation
Supply/Return
Connection
Gas Connection
Size
Intake/Exhaust
Dia.
Shipping
Weight L W H
199VWH 66,000–199,000 48,000–191,040 1¼” NPT ¾” 3” PVC Sch. 40 126 lbs. 24.50 18.25 25.88
399VWH 100,000–399,000 96,000–343,040 2” NPT 1¼” 4” PVC Sch. 40 267 lbs. 44.25 18.25 25.88
199 VWH at 20GPM
Pressure Drop for Tube Length of 1¼” Copper
(10) 90° Elbows ad (2) Tees (Side Outlet)
with Munchkin 199 VWH
1¼” Tube Length 20’ 30’ 40’ 50’ 60’
20 GPM 21.65 22.62 23.6 24.56 25.53
399 VWH at 40GPM
Pressure Drop for Tube Length of 2” Copper
(10) 90° Elbows and (2) Tees (Side Outlet)
with Munchkin 399 VWH
2” Tube Length 20’ 30’ 40’ 50’ 60’
40 GPM 24 24.37 24.74 25.11 25.48

6
GENERAL INFORMATION
DIMENSIONS
Figure 1-2

GENERAL INFORMATION
7
GENERAL
1. Munchkin VWH is supplied completely assem-
bled as a packaged boiler. 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
Heat Transfer Products, Inc. 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 VWH is certified for closet
installations with zero clearance to com-
bustible construction. In addition, it is design
certified for use on combustible floors.
2. Refer to Figure 1.1 for the recommended clear-
ance to allow for reasonable access to the boil-
er. Local codes or special conditions may
require greater clearances.
COMBUSTION AND VENTILATION AIR
1. The Munchkin VWH is designed only for oper-
ation with combustion air piped from outside
(sealed combustion). PVC pipe must be sup-
plied 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 lay-
out of the boiler installation to minimize the
possibility of interferences with new or exist-
ing 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 the Munchkin VWH to the
Storage Tank: 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.
Figure 1-3
C. PRE-INSTALLATION REQUIREMENTS

8
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.”
D. PRESSURE RELIEF VALVE
A pressure relief valve is installed into the right front side of the manifold. It is required that it meets
the requirements of ANSI/ASME Boiler and Pressure Vessel Code, Section IV or CSA B51: Boiler
Pressure Vessel and Piping Code as applicable for heating boilers. A ¾” pipe connected to the pressure
relief valve must be directed to a floor drain or suitable location within 6” of a drain or floor. To protect
the valve from freezing, do not plug or cap the pressure relief valve.
GENERAL INFORMATION
NOTICE
Service clearance of the Munchkin
1. The front of the appliance needs 24" of clearance for service minimum. It may have
a non-rated or combustible door or access panel and must have a minimum of 24"
clearance.
2. The left side of the heater is 12" clearance
3. The right side of the heater is 12" clearance
4. The top of the heater is 15" clearance.
WARNING
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.
NOTICE
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) for Condensate Requirements.
DANGER
Serious explosion causing property damage and/or loss of life could result. Under no
circumstances should the relief valve be eliminated, capped or plugged.

9
ELECTRICAL
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 circulator connection. All
electrical wiring must be performed by a qualified licensed electrician in accordance with National
Electrical Code ANSI/NEPA 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.
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.
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.
DANGER
IT IS VERY IMPORTANT THAT THE BUILDING GROUND IS INSPECTED BY A
QUALIFIED ELECTRICIAN PRIOR TO MAKING THIS CONNECTION!
DANGER
IT IS EXTREMELY IMPORTANT THAT THIS UNIT BE PROPERLY GROUNDED!

10
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 7” 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 for the
399VWH is 11/4” with a mandatory 1 x 11/4reducing coupling (provided). Threaded into the branch of
a 11/4” tee and a drip leg fabricated as per the national fuel gas code. The 199VWH has a 3/4” gas supply
nipple with a 1/2x 3/4reducing coupling (provided) which is to be threaded into the branch of a 3/4” tee.
You must ensure that the entire gas line to the connection at the Munchkin is no smaller than 11/4”
for the 399VWH and 3/4” for the 199VWH. 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 1/2PSI, 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)
WARNING
Failure to follow all precautions could result in fire, explosion or death!
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

11
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 7" 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 prop-
erly purged by the gas supplier or utility. Failure to properly purge the lines or improper line siz-
ing, 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 con-
nection to the Venturi and blower.
WARNING
Failure to follow all precautions could result in fire, explosion or death!

12
VENTING
PART 4. VENTING
A. APPROVED VENTING MATERIALS
EXHAUST VENT
Use Plastic 3” and 4” and 6” 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-1784 Class 12454-B, Formerly desig-
nated Type 1, Grade 1.
2. CPVC (Chlorinated Polyvinyl Chloride) Class 23447-B, Formerly designated Type IV, Grade 1 con-
forming 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.
INTAKE VENT
Use the same material as used for exhaust. Plastic Pipe or Cellular Foam Core Pipe may be used for
the inlet only, NEVER ON EXHAUST PIPING!
B. VENTING THE MUNCHKIN VWH IN 3”, 4” OR 6” PLASTIC PIPE
DANGER
Foam Core Pipe is not to be used in connecting the exhaust pipe.
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.
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.
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.

13
VENTING
The inlet pipe on the back of the cabinet is 3" for the 199 VWH and 4" for the 399 VWH. 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 for intake and exhaust (each
elbow = 5' of pipe) should not exceed 85'. The combined vent length should not be less than a com-
bined 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 guidelines below.
1) Never vent into a walkway, patio area, alley or otherwise public area less than 7' from the
ground. (See detail below 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 conden-
sation 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, including roof overhang.
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 sec-
tion. Use these layouts as guidelines: certain site conditions such as multiple roof lines/pitch-
es may require venting modifications (consult factory). The air inlet must be a minimum of 1’
vertically above the maximum snow level. It is very important that there are no other vents,
chimneys or air inlets in any direction for at least 4’.
NOTICE
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 VWH.

14
VENTING
RECOMMENDED VENTING CLEARANCES PER THE NATIONAL FUEL GAS CODE*
All venting must be properly supported. The Munchkin is not intended to support any venting
whatsoever. All piping, glue, solvents, cleaners, fittings and components, must conform to ASTM
(American Society for Testing and Materials), and ANSI (American National Standards Institute). It is
recommended that you use one of the optional vent kits specifically designed for Munchkin installa-
tions, available from Heat Transfer Products, Inc.
Example: Installation requires the following material for both inlet and exhaust piping for the
Munchkin 199VWH and the 399VWH.
Required: 4 Pcs. 90 degree elbow (4 x 5 = 20 Equivalent Feet) = 20 Equivalent Feet
Required: 20' of Plastic PVC Pipe (20 x 1 = 20 Equivalent Feet) = 20 Equivalent Feet
Total Friction Loss in Equivalent Feet (20 + 20 = 40 Equivalent Feet) = 40 Equivalent Feet
C. LONGER VENT RUNS
CAUTION
Flue Gas will condense as it exits the vent termination. This condensate can freeze on
exterior building surfaces which may cause discoloration of these surfaces.
Consideration should be given to the plume of condensation that exits the exhaust
which may affect the cosmetic appearance of the building.
12 in.minimum
Forced air
inlet
Grade
3 ft.minimum
Less
than 10 ft.
terminal
(see 10.8.1)*
draft vent
Mechanical
C
12 in.minimum
Direct vent terminal clearance
Minimum clearance, C
Input (Btu/hr)
4 ft.minimum
12 in.minimum
minimum
vent terminal
Mechanical draft
(see 10.8.2)*
4 ft.
Clearance (in.)
10,000 or less
10,001 to 50,000
Over 50,000
(see 10.8.3)*
6
9
12
For SI units: 1 ft = 0.305 m; 1 in. = 25.4 mm;
1 Btu/hr = 0.293 W
EXIT TERMINALS OF MECHANICAL DRAFT AND DIRECT-VENT VENTING SYSTEM
* REFERENCE: THE NATIONAL FUEL GAS CODE 2002 EDITION
*IMPORTANT NOTE
HEAT TRANSFER
PRODUCTS
RECOMMENDS A
MINIMUM
CLEARANCE OF 4
FEET WHERE THE
PLUME CAUSED BY
THE UNIT MAY
OBSTRUCT VIEWS
OR AFFECT THE
COSMETIC LOOK OF
THE BUILDING.
NOTICE
Do not exceed the 125 foot maximum requirement for (intake plus exhaust piping
added together). Consider fitting allowance shown in friction loss equivalent table on
the following page.

15
The connection of air inlet and exhaust vent at the heater must remain 3” for 199VWH and 4” for
399VWH and each vent must extend from the heater a minimum of 15 equivalent feet before transi-
tioning to a 4” vent for the 199VWH and 6” vent for the 399VWH. The overall extended maximum
length of pipe on the inlet and exhaust combined, must not exceed 125 equivalent feet. Listed below
are the 3”, 4” and 6” size equivalent table.
Example: Installation requires the following material for both the inlet and exhaust piping when
extending the vent run for the Munchkin 199VWH.
3" Vented Appliance
2 Pcs. – 3" 90 degree elbow (2 x 5 = 10 Equivalent Feet) = 10 Equivalent Feet
20' of 3" Plastic PVC Pipe (20 x 1 = 20 Equivalent Feet) = 20 Equivalent Feet
Total of 3" Equivalent Piping with Fittings = 30 Equivalent Feet
Requirements for 4" Venting
6 Pcs. – 4" 90 degree elbows (6 x 3 = 18 Equivalent Feet) = 18 Equivalent Feet
4 Pcs. – 4" 45 degree elbows (4 x 1 = 4 Equivalent Feet) = 4 Equivalent Feet
40' of 4" Plastic PVC Pipe (40 x 1 = 40 Equivalent Feet) = 40 Equivalent Feet
Total of 4" Equivalent Piping with Fittings = 62 Equivalent Feet
Total Friction Loss in Equivalent Feet for both 3" and 4" (30 + 62 = 92
Equivalent Feet) = 92 Equivalent Feet
D. HEATER REMOVAL FROM A COMMON VENT SYSTEM
At the time of removal of an existing heater, the following steps shall be followed with each appli-
ance remaining connected to the common venting system placed in operation, while the other appli-
ances remaining connected to common venting system are not operating.
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and horizontal pitch to determine if there
is blockage, leakage, corrosion or other deficiencies that could cause an unsafe condition.
DANGER
The Munchkin is not intended to be common vented with any other
existing appliance!
VENTING
Friction Loss Equivalent in Piping and Fittings
Fittings or Piping Equivalent Feet
90 degree elbow = 5
45 degree elbow = 3
Coupling = 0
air inlet tee = 0
Plastic Pipe = 1
concentric vent kit = 3
vent kit = 0
WARNING
Transitioning into a larger diameter pipe should be done in the Vertical position to
avoid condensation blockage. If done in the horizontal position check to make sure
condensation blockage will not occur.

16
VENTING
3. If practical, close all building doors, windows and all doors between the space in which the
appliance remains connected to the common venting system located and other spaces in the
building. Turn on clothes dryers and any appliances not connected to the common venting
system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, at maximum
speed. Do not operate a summer exhaust fan. Close all fireplace dampers.
4. Place in operation the appliance being inspected. Follow the lighting instructions. Adjust the
thermostat so the appliance will operate continuously.
5. 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.
6. After it has been determined that each appliance remaining connected to common venting
system properly vents when tested as outlined, return doors, windows, exhaust fans, fire-
place dampers and any other gas burning appliance to their previous condition of use.
7. Any improper operation of the common venting system should be corrected so the installa-
tion conforms with the National Fuel Gas Code, ANSI Z223.1. When resizing any portion of
the common venting system, the common venting system should be resized to approach the
minimum size as determined using the appropriate tables in Appendix G in the National Fuel
Gas Code , ANSI Z 223.1
E. CONDENSATE REMOVAL
This is a condensing high efficiency appliance, therefore this unit has a condensate removal system.
Condensate is nothing more than water vapor, derived from the combustion products, similar to an
automobile when it is initially started. It is very important that the condensate line is sloped away
from and down to a suitable inside drain, if the condensate outlet on the Munchkin is lower than the
drain, you must use a condensate removal pump (kit available from Heat Transfer Products, Inc.) A
condensate filter, if required by local authorities, can be made up of lime crystals, marble or phos-
phate chips will neutralize the condensate. This can be done in the field by the installer or you may
purchase one from Heat Transfer Products, Inc. It is also very important that the condensate line is
not exposed to freezing temperatures, or any other type of blockage. Plastic tubing should be the
only material used for the condensate line. Steel, brass, copper or others will be subject to corrosion
or deterioration. A second vent may be necessary to prevent condensate line vacuum lock if a long
horizontal run is used. An increase to 1” tubing may be necessary.

17
VENTING
Figure 4-1: Sidewall Vent with Tee (Intake) &
Coupling (Exhaust) for standard floor
units
3” piping for 199VWH
4” piping for 399VWH
**IMPORTANT NOTE: All vent pipes must be glued, prop-
erly supported and the exhaust must be pitched a mini-
mum of a ¼" per foot back to the boiler (to allow drainage
of condensate). Always increase pipe in vertical position.
Never increase pipe size in horizontal position.
Figure 4-2: Sidewall Vent with Tee (Intake) &
Coupling (Exhaust) for standard floor
units
3” piping for 199VWH
4” piping for 399VWH
**IMPORTANT NOTE: All vent pipes must be glued, prop-
erly supported and the exhaust must be pitched a mini-
mum of a ¼" per foot back to the boiler (to allow drainage
of condensate). Always increase pipe in vertical position.
Never increase pipe size in horizontal position.
Figure 4-3: Sidewall Vent with V1000 or V2000 kit
for standard floor units
3” piping for 199VWH
4” piping for 399VWH
**IMPORTANT NOTE: All vent pipes must be glued, prop-
erly supported and the exhaust must be pitched a mini-
mum of a ¼" per foot back to the boiler (to allow drainage
of condensate). Always increase pipe in vertical position.
Never increase pipe size in horizontal position.
DIAGRAMS FOR SIDEWALL VENTING
Figure 4-4: Sidewall Vent with 4” concentric vent
kit (KGAVT0601CVT) for standard floor
units
3” piping for 199VWH
4” piping for 399VWH
**IMPORTANT NOTE: All vent pipes must be glued, prop-
erly supported and the exhaust must be pitched a mini-
mum of a ¼" per foot back to the boiler (to allow drainage
of condensate). Always increase pipe in vertical position.
Never increase pipe size in horizontal position.

18
VENTING
DIAGRAMS FOR VERTICAL VENTING
Figure 4-5: Roof Vent with tee (intake) & coupling
(exhaust) for standard floor units
3” piping for 199VWH
4” piping for 399VWH
**IMPORTANT NOTE: All vent pipes must be glued, prop-
erly supported and the exhaust must be pitched a mini-
mum of a ¼" per foot back to the boiler (to allow drainage
of condensate). Always increase pipe in vertical position.
Never increase pipe size in horizontal position.
Figure 4-6: Roof Vent with 3” concentric vent kit
(KGAVT0601CVT) for standard floor
units
3” piping for 199VWH
4” piping for 399VWH
**IMPORTANT NOTE: All vent pipes must be glued, prop-
erly supported and the exhaust must be pitched a mini-
mum of a ¼" per foot back to the boiler (to allow drainage
of condensate). Always increase pipe in vertical position.
Never increase pipe size in horizontal position.

19
PIPING
PART 5. PIPING THE MUNCHKIN VWH TO THE STORAGE TANK
The Munchkin is designed to be connected to a storage tank to supply domestic hot water. Heat
Transfer Products has available storage tanks that are 80/119 gallon size storage tanks constructed in
either Stainless Steel or Glass lined construction. These storage tanks will be directly connected to the
Munchkin VWH supply and return connection. Connect the cold water supply to both the storage
bottom port and the supply side of the Munchkin VWH (shown in Piping details, this section) It is
important that you install a flow check on the supply line of Munchkin VWH before you connect feed
line to the storage. This will allow the cold feed to flow through the storage tank first and not the
Munchkin VWH. It is recommended that you install shut off valves on the cold feed line for ease of
future service. If there is a back flow preventer, or any type of no return valve in the system, then you
must install an additional tee for a suitable potable hot water expansion tank. Connect the Storage tank
return line to the return connection located on the Munchkin VWH (shown in Piping details, this
section). Then connect your hot water outlet located on the storage tank to your hot water plumbing
lines.
A. EXPANSION TANK
A potable hot water expansion tank my be required to offset the water expansion as the water is
heated. In most city plumbing systems, the water meter has a no return or back flow device built into
the system to prevent a back flow of water back into city mains. Some states require back flow pre-
venters on all incoming water supplies. Under these circumstances, you will need a hot water expan-
sion tank listed for potable water use. The expansion tank should be located on the cold inlet piping
close to the water heater. It is important that you follow the expansion tank manufacturer’s installa-
tion guidelines when installing any expansion tank.
See the piping illustrations included in this section, Figs. 5-2 to 5-9 for suggested guidelines in
piping the Munchkin heater with either zone valves or circulator pumps.
*Please note that these illustrations are meant to show system piping concept only, the installer
is responsible for all equipment and detailing required by local codes.
B. HIGH VELOCITY CIRCULATOR PUMP
Every Munchkin VWH is shipped with a high velocity circulating pump to assure the correct amount
of continuous flow through the all stainless steel heat exchanger at all times. If a replacement of the
high velocity circulator pump is needed, it must match the performance of the pump provided with
the Munchkin VWH package. NOTE: The circulator must be designed for potable water systems.
WARNING
Plumbing of this product should only be done by a qualified, licensed plumber in
accordance with all local plumbing codes.
WARNING
NEVER USE DIELECTRIC UNIONS OR GALVANIZED STEEL FITTINGS WHEN
CONNECTING TO A STAINLESS STEEL STORAGE TANK.
WARNING
When raising tank temperature, you increase the risk of scalding – Please use a water
tempering or mixing valve and extreme caution. Consult codes for conformance.

20
PIPING
Piping Symbol Legend
circulator (open loop)
(w/ isolation flanges)
gate valve
globe valve
ball valve
swing-check valve
spring-loaded check valve
hose bib / boiler drain
diaphragm-type
expansion tank
(for potable water)
anti-scald rated
mixing valve
pressure gauge
pressure relief valve
(or P&T relief valve)
union
Munchkin heater
vacuum breaker
T/P temperature /
pressure gauge
flow switch
Superstor Ultra
Storage Tank
PIPING ILLUSTRATIONS
Fig. 5-1