HTP Munchkin High Efficiency Heater User Manual
Installing, Operating & Maintaining
MUNCHKIN HIGH EFFICIENCY HEATER
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.
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
WHAT TO DO IFYOU 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.
MH27745
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.
HEAT TRANSFER PRODUCTS, INC.
120 BRALEY RD., E. FREETOWN, MA 02717
TABLE OF CONTENTS
PART 1
GENERAL INFORMATION
1-A. HOW IT OPERATES.........................................................1
1-B. LOCATION ........................................................................2
1-C. PRESSURE RELIEF VALVE............................................2
PART 2
2-A. ELECTRICAL CONNECTION ........................................2
PART 3
3-A. GAS CONNECTION.........................................................3
3-B. GAS PIPING ......................................................................3
3-C. GAS TABLE ......................................................................3
PART 4
VENTING
4-A. ALL MODELS 3 VENTED.............................................4
4-B. FOR LONGER VENT LENGTHS....................................5
4-C. VENTING TABLE .........................................................5-6
4-D. CLEANER/CEMENT........................................................6
4-E. CONDENSATE..................................................................6
4-F. VENTING TABLES ..........................................................7
PART 5
5-A. HYDRONIC HEAT PIPING..............................................8
5-B. FILL AND PURGE HEATING SYSTEM.........................8
PART 6
BOILER START UP
6-A. COMMON VENT TEST ...................................................9
6-B. ITEMS TO BE CHECKED BEFORE
LIGHTING THE MUNCHKIN.......................................10
6-C. LIGHTING INSTRUCTIONS .........................................11
PART 7
SERVICING
7-A. SEQUENCE OF OPERATION .......................................12
7-B. ADJUSTMENT SET POINTS
AND DIFFERENTIAL SETTINGS................................12
7-C. MUNCHKIN BOILER FAULT LED CODE ..................13
7-D. FAULT CONDITIONS ...............................................13-14
PART 8
8-A. MAINTENANCE PROCEDURES .................................15
8-B. BEFORE EACH HEATING SEASON ...........................15
8-C. COMPONENT DIAGRAM .............................................16
WARNINGS CAUTIONS
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 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 BOILERS, ANSI/ASME BOILER AND PRESSURE VESSEL
CODE, Section IV.
THE HEATER, GAS PIPING, WATER PIPING, VENTING AND ELECTRICAL MUST BE
INSTALLED BY TRAINED & QUALIFIED PERSONNEL FAMILIAR WITH INSTALLATION
PRACTICES AND LOCAL CODE AND 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;
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 neighbors’ phone.
Follow the gas suppliers’ 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 .
PART 1
GENERAL INFORMATION
1-A. HOW IT OPERATES
When the room thermostat calls for heat, the Munchkin control board will start the pump 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 boiler 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 prepurge the system before starting the Munchkin. The Munchkin controller will now start to modulate the pre-mix burner based
on analyzing the turn 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 fans have a low-voltage direct current drive 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 an indicator light which will pulse constantly in normal operation. When a problem occurs,
the indicator light will blink slowly to indicate the heater fault.
1
1-B. LOCATION
The Munchkin is designed for Installation on combustible flooring, in alcoves, basements, closets, utility rooms. The
Munchkin shall be installed so that the gas ignition system components are protected from water. This includes all related
piping and components.
Choose a location for your Munchkin, centralized to the piping system, along with consideration to vent pipe length. The
length of vent pipe increases the firing rate of the Munchkin decreases. You must also locate the Munchkin where it will not
be exposed to freezing temperatures. Additionally, you will need to place the heater so that the controls, inlet/outlet, and gas
valve are easily accessed. This Munchkin must not be installed outdoors, for it is certified as an indoor appliance only and
must be kept vertical and on a level surface. Also, care must be exercised when choosing the location of this appliance; where
leakage from the relief valve and from related piping will not result in damage to the surrounding areas or to the lower floors
of the building. A heater should always be located in an area with a floor drain or installed in a suitable drain pan.
Proper clearance must be provided around the Munchkin as follows: Sides, bottom, top, and back are 0" (zero clearance).
Venting is also zero clearance. The front of the appliance needs 24" of clearance for service minimum. It must have a nonrated or combustible door or access panel and should have a minumum clearance of 24" front, 15" top, 6" right side and 10" to
the left side. Under no circumstances, shall Heat Transfer Products Inc. be held liable for any such water damage
whatsoever. This heater must not be located near flammable liquids such as gasoline, adhesives, solvents, paint
thinners, butane, liquefied propane, etc., the controls of this appliance could ignite those vapors, causing an explosion.
1-C. PRESSURE RELIEF VALVE
A pressure relief valve is installed into the front right side manifold we recommend a WATTS "M 335 MI valve or
equivalent and meets the requirements of ANSI/ASME Section IV for heating boilers. A " pipe must be directed to a floor
drain or suitable location within 6" of 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.
PART 2
2-A. ELECTRICAL CONNECTION
The electrical connection for the Munchkin is on the left side of the unit. There is a ‰" knockout location for electrical
connection. All electrical wiring must be performed by a qualified licensed electrician in accordance with National Electrical
Code, or to the applicable local codes and standards. For your convenience we have labeled all the wire which needs to be
connected to operate the Munchkin. Caution: Do not remove labels on wires prior to disconnection. The electrical
requirements are for standard 120 volts, 60 Hz 10 amp service. This unit must be wired with #14 awg and fused for no more
than 15 amps. It is of extreme importance that this unit be properly grounded. There are two ground points in the
electrical compartment that must be connected to the building ground system. Connect the building to the green ground screw
and the green ground wire. It is very important that the building system ground is inspected by a qualified electrician
prior to making this connection.
The black wire is the hot lead and white wire is the neutral lead. Once all connections have been made the electrical
access may be closed. It is very important that the electrical power is not turned on at this time! A green LED is
provided on the main control board. This LED must be illuminated when the Munchkin is turned on forproper
operation.
WARNING:
THE MUNCHKIN MUST BE SET ON ALEVELSURFACE SO
CONDENSATION DOES NOT BACK UP INSIDE BOILER!
SERVICING - WARNING - CAUTION
Before servicing let the munchkin cool down! Shut off electrical and gas supply.
Failure to follow warning could result in severe burn, electrical shock, gas
leakage, fire or explosion.
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PART 3
3-A. GAS CONNECTION
The gas supply shall have a maximum inlet pressure of less than 14" water
column (350 mm), ‰ pound pressure (3.4 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, or 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 ‰" and it is mandatory that a " to ‰" reducing bushing (provided) is used, threaded into the branch of
a " 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 ". 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 following lighting instruction on page 11. Unscrew the
threaded mounting flange which is located on the gas valve which will prevent high pressure which may damage the gas
valve. In the event the gas valve is exposed to a pressure greater than ‰ PSI, 14" water column, the gas valve must be
replaced. Never use an open flame (lit match, lighter) to check gas connections.
3-B. GAS PIPING
1. Run gas supply line in accordance with all applicable codes.
2. Locate and install manual shutoff valves in accordance with state and local requirements.
3-C. GAS TABLE
Refer to Table (1) to size the supply piping to minimize pressure drop between meteror 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
Failur
e 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
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It is recommended that a soapy solution be used to detect leaks. Bubbles will appear on 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 or
regulator or gas line is undersized or in need of service. You can attach a meter to the incoming gas drip leg, by removing the
cap and installing the meter. The gas pressure must remain between 7" and 14" during stand-by and unit running heat cycle.
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
the failure of the Munchkin lighting off. 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 valve must not be replaced with a conventional valve under any circumstances. As an additional safety feature, this
valve has a flanged connection to the Venturi and blower.
PART 4
VENTING
4-A. ALLMODELS 3" VENTED
The inlet pipe on the back of the cabinet, use 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 burs, debris, ragged ends, and particles of PVC.
Exhaust pipe on the back of the cabinet will use 3" PVC, CPVC, ABS Schedule 40 or 80. For concrete construction or to
meet certain fire codes, exhaust piping inlet air pipe must be 3" CPVC Schedule 40 or 80, (only to meet local fire codes). The
balance of the inlet and exhaust piping may be PVC Schedule 40 or 80, or ABS solid only, NOT FOAM CORE.
The only approved exhaust vent materials are PVC Schedule 40 (NOT FOAM CORE PIPE!). Exhaust piping should be
sloped back to the connection on the Munchkin, at least …" 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 additionally 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.
2) Never vent over or under a window or over a doorway.
3) Never install a heat saver or similar product to capture waste heat from exhaust.
4) Always have 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 vent at least 3’ from an inside corner of outside walls.
8) Maintain at least 4’ clearance to electric, gas meters, and exhaust fans or inlets.
9) Very Important! Inlet air must be taken from outside of building, next to exhaust
outlet, no closer than 8".
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 1 thru 6. Use the following layout as a guideline; certain
site conditions such as multiple roof lines/pitches may require venting modifications (consult factory). The
air inlet must be a minimum of 1’ vertically above the maximum snow level or 24" which ever is greater.
The air inlet must also be a minimum of 10’ horizontally from the roof, and terminated with a tee. The
exhaust must be a minimum of 24" above the air inlet opening and terminated with a coupling. It is very
important that there are no other vents, chimneys or air inlets in any direction for at least 4’.
WARNING!!
It is extremely important to follow these venting instructions exactly. Failure to
follow the venting instructions can cause severe personal injury, death or
substantial property damage.
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