Calorex DIGITAL LOGIC AT400 Owner Operational Manual Download Page 5

GREEN POWER LIGHT: 

This light indicates that the heater has control power.

WARNING: This is not a supply line power indicator and caution should be used since
more than one power disconnection may be required to isolate the heater electrically.
WARNING: If the optional Time Clock Override is installed, you must shut off the water
pumps main power disconnect as well to eliminate all power to the heater.

GREEN HEATING LIGHT: 

This light indicates that the unit is heating and the compres-

sor is running.  The compressor starts after a 3 to 5 minute time delay.  NOTE: The water
pump must be running at the same time in order for the heater to run.

LED READOUTS:

When the unit has power, the LED will display the current water temperature. When
pressing the thermostat buttons the flashing readout will indicate the set temperature.
The following are LED code readouts for the internal sefety controls that regulate the
unit for various reasons.

LF = LOW WATER FLOW

LF = LOW WATER FLOW

LF = LOW WATER FLOW

LF = LOW WATER FLOW

LF = LOW WATER FLOW

This light indicates there is no water flow through the heater.  The heater is designed to
shut off whenever the water pump is not pumping water through the heater. If 

LF

LF

LF

LF

LF

 is on

while the water pump is running, the water pump may not be supplying enough flow
for the heater to operate properly.  During normal operation the heater turns off and on
with the water pump.

d

dd

dd

F = DEFROST MODE

F = DEFROST MODE

F = DEFROST MODE

F = DEFROST MODE

F = DEFROST MODE

This readout indicates that the internal defrost safety control has disabled the heater.
During cold weather where the air temperature drops below approximately 45 to 50
degrees (depending on humidity), the low refrigerant pressure switch (or defrost con-
trol) is designed to disable the compressor only. Once the unit is in defrost mode the
compressor will shut off for 1 hour while the fan continues to help deice and warm the
air coil.  After 1 hour the unit will attempt to restart.  If the air temperature has increased
to the operational range the compressor will continue to run, otherwise the compressor
will return to the defrost mode for another 1 hour delay cycle.

HP = HIGH REFRIGERANT PRESSURE SHUT OFF

HP = HIGH REFRIGERANT PRESSURE SHUT OFF

HP = HIGH REFRIGERANT PRESSURE SHUT OFF

HP = HIGH REFRIGERANT PRESSURE SHUT OFF

HP = HIGH REFRIGERANT PRESSURE SHUT OFF

This readout out indicates high refrigerant pressure. The high refrigerant pressure switch
is designed to shut the compressor and fan off if a heat buildup occurs for whatever reason.
Typically, the high refrigerant pressure switch will trip if the water flow through the heater is
restricted.  It may also trip if the air flow is restricted through the heater.

Page 5

TIME DELAYS:

30 second compressor delay when switching pool/spa modes.

5 minute compressor delay when T.C.O. enables in pool mode.

5 minute T.C.O. off delay when: switching from spa to pool mode, when temperature is

reached in pool mode, or if LF (low water flow) is displayed on LED.

If water pump loses prime there will be a 3 minute compressor delay.

Summary of Contents for DIGITAL LOGIC AT400

Page 1: ...NAL POOL SPA INSTITUTE V2 3 AT 2001 CalorexU S A LLC SWIMMING POOL SPA HEAT PUMPS NOTE Installers should see separate installation manual Model AT800 AT600 AT400 BLACK CABINET with DIGITAL CONTROL DIG...

Page 2: ...one of the most efficient ways to heat your pool or spa Your heat pump was manufactured by Calorex USA the very first company to produce swimming pool heat pumps Since making the very first pool heat...

Page 3: ...id refrigerant in the air coil absorbs the available heat in the ambient air transforming it into a gas The refrigerant gas is then pumped into the compressor When this warmed gas is com pressed it in...

Page 4: ...rt the water pump whenever the pool requires heat Once the pool is up to the set tempera ture the heater will stop and then 5 minuets later the water pump will stop When this button is set to the OFF...

Page 5: ...MODE F DEFROST MODE F DEFROST MODE F DEFROST MODE F DEFROST MODE This readout indicates that the internal defrost safety control has disabled the heater During cold weather where the air temperature...

Page 6: ...D display will show a constant readout of the actual cur rent water temperature To set the desired water temperature press either the or thermostat buttons While adjusting the set temperature the LED...

Page 7: ...at loss by as much as 80 and reduce heating costs as much as 50 Using a cover during the initial heat up period will greatly reduce the operational time needed 8 SPA HEATING When heating a spa it is a...

Page 8: ...is not restricted Make sure the unit can breathe well The cooler discharge air from the top should not accumulate and be drawn into the side air intake coils Keep all plants and shrubs trimmed away fr...

Page 9: ...IN THE POOL or SPA SKIMMER Chemicals placed in the skimmer will feed concentrated chemical or chlorine into the heat exchanger before it is diluted with the rest of the pool water Chemicals or chlo r...

Page 10: ...up A minimal air coil cleaning should be done as needed and at least two times per year If the heater is installed in a sandy or salty condition the air coil should be cleaned more frequently 3 To cle...

Page 11: ...equired to shut off or turn on power to the heater 5 Confirm that all heater controls thermostat thermostat selector switch reset tripper and optional auto heat switch if so equipped are in the correc...

Page 12: ...ns T Stat Relay Does Not Close Heater Does Not Activate After Delay Period Try Again or Possible Bad Time Delay Possible Bad T Stat Board Pot or Sensor 1 Hour Time Delay Activates Water Temperature is...

Page 13: ...ut notice 2000 Calorex U S A LLC MEMBER NATIONAL POOL SPA INSTITUTE Pool Heat Pump Manufacturers Association MEMBER 5826 Corporation Circle Ft Myers Florida 33905 888 297 3826 www calorexusa com calor...

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