AFTER START-UP
CHECKING WATER FLOW
Fire or flooding hazard. If the heater overheats and the burners fails to shut off, follow the instructions under To Turn Off
Gas to the Appliance, on page 13, and call a qualified service technician to repair the heater.
After start-up, the outlet water pipe should feel slightly warmer than the inlet pipe. If it feels hot, or if you hear the water
in the heater boiling, there may not be enough water flow to the appliance. Make sure that the filter is not plugged. If
water temperature remains high but the unit continues to operate, turn off the appliance and call your service technician.
SPRING AND AUTUMN OPERATION
If the pool is only used occasionally, lower the pool thermostat to 68° F (20° C) and leave the heater on. This will
keep the pool and the surrounding ground warm enough so that the heater should restore the pool to a comfortable
temperature within about one day.
WINTER OPERATION AND WINTERIZATION
Notice: Pentair recommends to use a blower to remove all of the water out of the heater in areas subject to freezing
temperatures while the heater is not being used.
Explosion hazard. Purging the system with compressed air can cause components to explode, with risk of severe injury or
death to anyone nearby. Use only a low pressure (below 5 PSI or 35 kPa), high volume blower when air purging the heater,
• If the heater has been drained for freezing condition, DO NOT TURN ON the heater until the system is circulating water.
• Water trapped in the heat exchanger can result in freeze damage to the exchanger or headers. Freeze damage is specifically
not covered by the warranty.
• When starting the heater for the swimming season with a water temperature below 50° F (10° C), the heater may be used
to heat the water; however, make sure that the heater operates continuously until the water temperature reaches the
heater's minimum setting of 68° F (20° C). During cold weather, if there is no danger of freezing, operate the filter pump
continuously even if the heater is not operating. If air temperatures are expected to drop below freezing (32° F/0° C), shut
down the heater and winterize it.
For outdoor heaters in freezing climates, shut the heater down and drain it for winter as follows:
1. Turn off the electrical supply to the heater and pump ay the main circuit breakers.
2. Close main gas control valve and manual gas valve (located outside the heater). See Figure 14 on page 20.
3. Open the main DRAIN COCK located on the bottom of the manifold adapter and drain the heater exchanges,
internal CPVC plumbing, and manifold adapter completely.
4. If the heater is below pool water level, be sure to close the isolation valves to prevent from draining the pool.
Isolation valves are not required and should not be used on heaters installed above pool water level, except when
needed for winterization valves.
5. Remove the two WATER PRESSURE SWITCHES located in the plumbing inlet assembly (see page 14).
Plug the water pressure switches ports to prevent insects and dirt from getting into the plumbing inlet assembly
Continue with Step 6 on next page.
Rev. C 4/2017
Section 4: Maintenance and Care
WARNING
WARNING
CAUTION
ETi 400 High Efficiency Pool and Spa Heater Installation and User's Guide
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