Munchkin MUNCHKIN HIGH EFFICIENCY HEATER with the "925" Controller manual Part 5. Piping

PIPING

PART 5. PIPING

A. HYDRONIC PIPING WITH CIRCULATORS OR ZONE VALVES

The Munchkin is designed to function in a closed loop 15 PSI System. To assure you that you have adequate pressure in the system, we have installed in the outlet manifold, a pressure switch that will not let the Munchkin operate without a minimum of 10 PSI water pressure. This assures you that if the system does have leak, the Munchkin will lock out (PRO on the display) before it damages the Stainless Steel Heat Exchanger. We have also included a Temperature and Pressure gauge which should be located on the Munchkin outlet to monitor the system pressure and outlet temperature from the Munchkin. It is important to note that the Munchkin has a minimal amount of pressure drop and must be figured in when sizing the circulators. Each Munchkin installation must have an Air Elimination device which will remove air from the system. Install the Munchkin so the gas ignition system components are protected from water (dripping, spraying, etc.) during appliance operation for basic service of circulator replacement, valves and other. Observe minimum 1” clearance around all un- insulated hot water pipes when openings around pipes are not protected by non-combustible materials. On a Munchkin installed above radiation level, some states and local codes require a low water cut off device at the time of installation. If the Munchkin supplies hot water to heating coils in air handler units, flow control valves or other devices must be installed to prevent gravity circulation of heater water in the coils during the cooling cycle. Chilled Water Medium must be piped in parallel with the heater. Freeze Protection for new or existing systems must use glycol that is specially formulated for this purpose. It includes inhibitors, which prevent the glycol from attacking the metallic system components. Make certain that the system fluid is checked for the correct glycol concentration and inhibitor level. The system should be tested at least once a year and as recommend by the producer of the glycol solution. Allowance should be made for the expansion of the glycol solution in the system piping. Example 50% by volume solution expands 4.8% in volume for the temperature increase from 32 F to 180 F, while water expands 3% with the same temperature rise.

CAUTION

The Munchkin should not be operated as a potable Hot Water Heater. It should not be used as a direct Hot Water Heating Device.

Basic steps are listed below, with Illustration, which will guide you through the installation of the Munchkin.

1.Connect the system return marked “Heater In”, make sure to install with pipe sealant com- pound. Threaded connections are 1 ¼” NPT Brass nipples located on the left hand side of unit.

2.Connect the system supply marked “Heater Out”, make sure to install with pipe sealant com- pound. Threaded connections are 1 ¼” NPT Brass nipples located on the left hand side of the unit.

3.Install Purge and Balance Valve or shut off valve and drain on system return to purge air out of each zone.

4.Install a Back Flow preventor on the Cold Feed Make-Up Water line.

5.Install a Pressure Reducing Valve on the Cold Feed Make-Up Water line, (15 PSI nominal on the system return). Check Temperature and Pressure Gauge which should read minimum pressure of 12 PSI.

6.Install a circulator on system supply. Make sure the circulator is properly sized for the system and friction loss.

7.Install an Expansion Tank on the system supply. Consult the tank manufacturer’s instruction for specific information relating to tank installation. Size the expansion tank for the required system volume and capacity.

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