Water Connections, Plumbing Connections

Installation (Plumbing)

WATER CONNECTIONS

Reversible Inlet/Outlet Connection

The MiniMax NT Low NOx heater is factory assembled with right side inlet/outlet water connections. The inlet/outlet header can be reversed for left side water connections without removing the heat exchanger.

Reversing Water Connections

Tools required:

1/4 in. Screw Driver

9/16 in. Socket and Wrench 1/2 in. & 9/16 in. Open Wrench

1.Remove the right and left large inspection plates.

2.Disconnect all wires from the high-limit switches except the short jumper wire.

3.Disconnect the pressure switch wiring.

4.Remove the temperature sensing bulb from the inlet/outlet header. Note: If needed, you may cut the wire ties holding them together.

5.Remove the 16 bolts holding the main inlet/ outlet head and return head in place, exchange the heads, using the new tube seals supplied with the heater, re-install the 16 bolts using moderate torque.

6.Install the temperature sensing probe by passing the wires through the hole provided on the left side of the brace panel. Route wires through the support bracket.

7.Reconnect all the high limit wires and the pressure switch wiring, routing the wires through the same hole as the thermostat sensor wires.

8.Re-install the two large inspection plates on the appropriate side.

PLUMBING

VALVES

When any equipment is located below the surface of the pool or spa, valves should be placed in the circulation piping system to isolate the equipment from the pool or spa.

Check valves are recommended to prevent back siphon.

CAUTION

Exercise care when installing chemical feeders so as to not allow back siphoning of chemical into the heater, filters or pump.

	TO	PUMP
POOL	POOL	FILTER
POOL		FILTER
HEATER	MANUAL
	BY-PASS
	GATE
	CHECK VALVE
	VALVE

Figure 9.	CHECK
	VALVE
	FROM
	POOL

PLUMBING CONNECTIONS

The MiniMax NT Low NOx heater has the unique capability of direct schedule 40 PVC plumbing connections. A set of bulkhead fittings is included with the MiniMax NT Low NOx to insure conformity with Pentair’s recommended PVC plumbing procedure. Other plumbing connections can be used.

CAUTION

Before operating the heater on a new installation, turn on the circulation pump and bleed all the air from the filter using the air relief valve on top of the filter. Water should flow freely through the heater.

Do not operate the heater unless water in the pool/ spa is at the proper level.

MANUAL BY-PASS

Where the flow rate exceeds the maximum 120 GPM, a manual bypass should be installed and adjusted. After adjustments are made, the valve handle should be removed to avoid tampering.

Model	Min. (GPM)	Max. (GPM) *

200	20	120

250	30	120

300	30	120

400	40	120

* Do not exceed the maximum recommended flow rate for the connecting piping.

BELOW POOL INSTALLATION

If the heater is below water level, the pressure switch must be adjusted. This adjustment must be done by a qualified service technician. See Page 22, Figure 20.

Rev. C 11-1-01

P/N 471593