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NS SPLIT INSTALLATION MANUAL
Plumbing Installation
1. Inspect the dip tube in the water heater cold inlet for a check valve. If a check valve is present it must be removed
or damage to the desuperheater circulator will occur.
2. Remove drain valve and tting.
3. Thread the 3/4-inch NPT x 3-1/2-inch brass nipple into the water heater drain port.
4. Attach the center port of the 3/4-inch FPT tee to the opposite end of the brass nipple.
5. Attach the 1/2-inch copper to 3/4-inch NPT adaptor to the side of the tee closest to the unit.
6. Install the drain valve on the tee opposite the adaptor.
7. Run interconnecting tubing from the tee to DHW water out.
8. Cut the cold water “IN” line going to the water heater.
9. Insert the reducing solder tee in line with cold water “IN” line as shown.
10. Run interconnecting copper tubing between the unit DHW water “IN” and the tee (1/2-inch nominal).
The recommended maximum distance is 50 feet.
11. To prevent air entrapment in the system, install a vent coupling at the highest point of the interconnecting lines.
12. Insulate all exposed surfaces of both connecting water lines with 3/8-inch wall closed cell insulation.
Note: All plumbing and piping connections must comply with local plumbing codes
.
Heat Recovery Startup
1. Close the drain valve to the water heater.
2. Open the cold water supply to the tank.
3. Open a hot water faucet in the building to bleed air from the system. Close when full.
4. Open the pressure relief valve to bleed any remaining air from the tank, then close.
5. If so equipped, unscrew the indicator plug 1 turn on the motor end of the pump until all air is purged from the pump,
then tighten the plug. Use vent couplings to bleed air from the lines.
6. Carefully inspect all plumbing for water leaks and correct as required.
7. Before restoring electrical supply to the water heater, adjust the temperature setting on the tank.
• On tanks with both upper and lower elements, the lower element should be turned down to the lowest setting,
approximately 100°F. The upper element should be adjusted to 120°F to 130°F. Depending upon the specic
needs of the customer, you may want to adjust the upper element differently.
• On tanks with a single element, lower the thermostat setting to 120°F.
8. After the thermostat(s) is adjusted, replace the access cover and restore electrical supply to the water heater.
9. Make sure that any valves in the desuperheater water circulating circuit are open.
10. Turn on the unit to rst stage heating.
11. The DHW pump should be running. When the pump is rst started, open the inspection port 1 turn (if equipped) until
water dribbles out, then replace. Allow the pump to run for at least ve minutes to ensure that water has lled the
circulator properly. Be sure the switch for the DHW pump (SW4) is “ON”. The DHW “OFF” LED on the unit should not
be illuminated.
12. The temperature difference between the water entering and leaving the desuperheater should be 5°F to 15°F. The
water ow should be approximately 0.4 GPM per ton of nominal cooling.
13. Allow the unit to heat water for 15 to 20 minutes to be sure operation is normal.
CAUTION: Never operate the DHW circulating pump while dry. If the unit is placed in operation
before the desuperheater piping is connected, be sure that the pump switch is set to the OFF
position.