HTP Munchkin High Efficiency Heater - Manual (Page 3)

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 pre-
purge 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.
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