MegaTherm Commercial Pool Heating Boiler

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If the inlet temperature is LESS THAN 100°F:

With the bypass valve “A” fully open, throttle (turn down) outlet valve “B” slightly. Observe the inlet thermometer for 5 minutes to see where the inlet temperature stabilizes. If it remains under 100°F, throttle outlet valve “B” a little more. Repeat as necessary. If the inlet temperature rises above 100°F, open outlet valve “B” slightly until the inlet temperature stabilizes as close to 100°F as possible (plus or minus 2°F).

If the inlet temperature is MORE THAN 100°F. If outlet valve “B” has been throttled partially closed, open it slightly, wait 5 minutes, and, if the temperature is not down to 100°F (plus or minus 2°F) open it some more. If bypass valve “B” is fully open and you are still seeing inlet water temperatures in excess of 100°F, you can adjust bypass valve “A”. Throttle it (turn down) slightly towards closed, and wait until the inlet water temperature stabilizes again. Repeat as necessary.

When the inlet temperature is stabilized at 100°F, either lock the valve handles, remove them, or prominently mark them to prevent tampering or accidental changes to the valve positions.

If the pool water temperature needs to be raised more than 10° F to reach a comfortable swimming temperature, inspect and re-adjust the valves twice a day to maintain the 100°F inlet water temperature.

3.To prevent nuisance high limit tripping, set the adjustable pump time delay relay to 10 minutes for all models. This allows the boiler pump to circulate water through the heat exchanger after the burners shut off, recovering all residual heat in the metal components.

4.The boiler outlet temperature with the bypass adjusted as detailed above should be less than 142°F. The normal range will be 10 to 37°F higher than the inlet temperature. If it exceeds 142°F, please contact the Service Department at 800-900-9276, extension 5406 for instructions. Outlet temperatures in excess of 142°F may cause intermittent high limit tripping.

POOL OPERATING CONTROL ADJUSTMENT:

5.Adjustable Differential Feature: Remove the cover from the control box and verify that the white differential potentiometer is set at about 2°F (1°C). NOTE: a 2°F differential means that, if the thermostat is set at 80°F, the heater will come on at 78°F and go off when the pool reaches 80°F. The 2°F value is a good starting point for most installations. This differential may be adjusted up or down to suit individual applications.

6.The operating control temperature setting can be

Manual Reset

Flow

Low Water

High Limit

Switch

Cutoff

 

 

(Optional)

Figure 14. Safety Components.

Spark ignition

Standing pilot

Thermo-

couple

Figure 15. Pilot Burners.

adjusted incrementally to obtain the desired pool operating temperature.

3.5 Heater Shut Down

1.If heater is firing, turn operating control to lowest value, wait 10 minutes for pump to stop running, then turn power switch to off.

2.If heater is not firing, turn power switch to off.

3.6Spring and Fall Operation Stand-by Service

Turn the thermostat down to approximately 70°F (21°C). This will prevent the pool and surrounding ground from becoming chilled and also permit the pool to be raised to swimming temperature in a shorter time.

A pool may be maintained at a lower temperature than 70°F (21°C) with some increased likelihood of condensation and damage to the unit. Models 500 through 1010 will maintain an inlet temperature of 85°F (29°C) to 90°F (32°C) (if the bypass is properly adjusted) with a pool temperature of 60°F (16°C). Models 1200 and 1430 can maintain the above with a pool temperature of 65°F (18°C). For models 1670

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Pentair MT Sizes 500 important safety instructions Heater Shut Down, Spring and Fall Operation Stand-by Service