Lochinvar GAS HEATER FOR COMMERICAL POOL APPLICATIONS service manual Prepurge

Installation and Service Manual

PREPURGE

(Ignition Module Function)

Once the ignition module sees a 24VAC input from its pressure switch, it runs the blowers for approximately 15 seconds in order to purge the combustion chamber of any unburned fuel/air mixture.

IGNITER WARM-UP AND PROVING

(Ignition Module Function)

Once the ignition module has completed its prepurge period, it turns on the hot surface igniter. Once the hot surface igniter’s current draw reaches a proper level, the ignition module begins an additional period of approximately 25 seconds for the igniter to ensure the ignition temperature is attained to ignite the fuel/air mixture.

IGNITER

(Controlled by Ignition Module)

One igniter is provided in order to ignite the fuel/air mixture and its operation and timings are controlled by the ignition module.

IGNITION AND FLAME PROVING (Ignition Module Function)

Once the warm-up and proving period has been completed, the ignition module sends 24VAC to the gas valves on approximately half of the pool heater. These gas valves should open and allow gas to flow to the burners. The fuel/air mixture should ignite from the hot surface igniter. Once this voltage has been sent to the valves, the hot surface igniter is turned “OFF”. The ignition module then monitors and proves the presence of the flame and will either allow operation to continue or shut down the gas valves should flame not be proven and proceed to a Flame Failure condition. If flame was proven briefly during the ignition period, the module may not proceed to Flame Failure, but rather post-purge and then go into another trial for ignition.

SOFT-START

MODELS 990,000 - 2,070,000 BTU/HR ONLY (Controlled by Temperature Controller)

A small time delay is provided to delay the opening of approximately half of the valves until the first half of the valves have opened and the gas has successfully ignited and established flame on the burners.

HEAT TRANSFER PROCESS (Gas Valves, Burner and Heat Exchanger)

Once flame has been proven, the ignition module will hold the gas valves open as long as there is proof of flame and a call for heat is present. When the temperature of the water reaches that of the programmed set point, the pool heater will be shut down.

POST-PURGE(Ignition Module Function)

When 24VAC is removed from the ignition module’s thermostat input, the module turns “OFF” the gas valves and maintains the blowers for approximately 25 seconds in order to allow the combustion chamber to be purged of all combustion by-products.

IDLE

(Temperature Controller Function)

After completion of the post-purge cycle, the pool heater will go into an idle state whereby the temperature controller continuously monitors the water temperature until the water temperature drops to levels that require additional heat.

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