Correct Tech, Inc. - Quality Spa Controls and Equipment

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USING CT250 Printed Circuit Board


 No display at topside

Check miss-wire fuse between J23 and J12 – If blown check Incoming wiring L1, L2, N are correct.

Check that connection to main board is clean and sound at J8

Test a new topside control.

Check for 120V primary power going into the transformer and for 12V secondary power out of the transformer to J6 & J7 on the board before replacing the transformer.

Replace board if there is 12V to J6 & J7

 Display flashes " th1 / 39 " or  “- - - / 39" on system start up 

    If the fill water is less than 39F and will stay in freeze protect mode until over-ridden or the water temp rises above 39F

    ( see freeze protect information )

    Check that temperature sensing probe connection to main board is clean and sound at location J2.

    Try new temperature sensing probe.

Display flashes " th2 / current temperature " or “ - - - / current temperature" on system start up.

    Check that the temperature-sensing probe connected to the main board is clean and sound at location J1.

    Try new temperature sensing probe

Display flashes " th2 / 39 " or “ - - - / 39”on system start 

    This indicates that both thermisters are detecting tub water temperature of less than 39F / 4C or they are both disconnected (open). Pump(s) and blower will run in this condition.

Display flashes " OH "  or the “ Current Temperature” ( OVER HEAT) 

    This indicates that the spa water temp is over 112F. The system should be shut down in this state and will re-start automatically when the water cools below 112F.

Display flashes " hot " or “ Current Temperature" ( OVER HEAT )

    This indicates that the heater body is over 112F. The system should be shut down in this state and will re-start automatically when the water cools below 112F.

Display flashes " HL " or “ Current Temperature" ( HIGH LIMIT )

    This indicates that either the heater or the spa has reached 118F or higher. The system will not re-start automatically.  To re-start the system, the water temperature must be below 112F and the heater key at the topside control must be pressed.

     If "HL" stays on and cannot be disarmed, there has been high amperage drawn through the board - 48 Amps total max. - replace board.

Display flashes " FLO"  or "- -"

    This indicates a flow problem where the pressure switch is not closing

    Check that filters are clean

    Check for a flow obstruction or closed valve

    Check that topside program is set up correctly for pump speeds  

  ( see factory-programming instruction )

Display flashes " FLC" or “- -"

    This indicates that the pressure switch is stuck in the closed position

    Turn the power off and check the pressure switch for continuity using 

    an Ohms meter for resistance or other buzzer style continuity tester.

      Erratic operation or 0 at topside panel

    Check  for proper connection at J8

     Shut off system and restart

     Check for debris inside topside panel control housing

    Check cable connection at the topside control remove, clean reconnect

    Try new topside control

     Replace main board

No heat

Check the topside control for " HL". This indicates that the system has      overheated. Make sure the temperature has fallen to less than 112F and press the heat key to reset.

Check that temperature set point is higher than actual tub temperature.

Check for flashing LED at topside control to indicate heat demand

Check that filters are clean

Check to see if the pilot light at the equipment panel is on. This indicates if power is actually getting to the heater element. If this light is on and there is still no heat, the element should be checked for continuity. If the element is open, it needs to be replaced .  

If the pilot light still does not turn on, then the pressure switch may need to be adjusted. The pressure switch is located on the heater body and has a small wheel on it. This wheel should be turned counter clockwise to allow the heater to run on less water flow / pressure. This pressure switch is a protection switch that is meant to turn the heater off if the pump fails to operate or if there is not enough pump pressure. A test to see if the pressure switch has been adjusted correctly is to unplug the circulation pump and see if the heater shuts off. It should operate again when the pump is plugged back in. The heater should not be allowed to operate under static ( gravitational ) pressure when the pump is not on as it will cause an instant overheat.

 If a flow switch is used it must be checked for continuity when closed.

Replace the circuit board if the above remedies do not work

Note: Some systems have fixed pressure switches to prevent tampering. It is highly recommended that the spa plumbing is checked for obstructions first.

Temperature readout is wrong

Remove temperature sensor / thermister from the tub location and submerge it directly into the water. This will verify if the sensor has been installed where ambient air has affected it or if it is defective.

Insulate the through wall dry well so the ambient air does not influence the temperature measurement


If the water is too hot and the high limit has tripped, the water must be allowed to drop to less than 112F before it will reset. Reset by pressing the heat key at the topside control or restarting the system

The circulation of the water may be too low, allowing the heater body to overheat. Be sure that all valves are fully open to allow maximum water flow over the heater element.

The friction and radiant heat from the pump motor can cause an extremely high ambient temperature around the spa and the equipment causing an overheat condition. If this condition is suspect, try running the spa with the equipment door off to see if it still overheats.

Pump(s), Blower or light does not shut off

System may be in freeze protect mode if water is less than 52

( this temp level may vary with custom software ) System will run in protection mode and you will not be able to control the pumps, heater or optional blower. You must introduce warm water into the spa or manually over-ride the system or wait for the system to heat up on its own. Depending on outdoor temp this can take several hours.

Try new topside control

Replace main board

Circulation pump does not work

Check the fuse and power connections.

Light does not work

Press Light Key at top side

Check bulb

Check 12V out to light at J4 & J5

Filter Cycle does not operate

Adjust the temperature set point to be within 2 degrees F of the actual water temperature. If the water temperature creeps 2 degrees F higher than the set temp, the system will shut off to allow the water to cool. When the water cools down to the desired set point, filtration will resume. Proper ventilation of the equipment will minimize this interruption.

Ground Fault Interrupter Trips

Check if it does it only when heat turns on, if so check element by removing the power to the element terminal and turn the heat on. If it only faults when the element is connected with power, the element has a ground fault and must be replaced

This can be done with the pump(s), blower, ozonator, or any other peripheral equipment as a process of elimination to see where the fault may be.

 Be sure that the neutral on the GFCI has been wired properly in the main panel.  


All connections should be checked that they are secur

Always exercise general electrical common sense for safety.

Please do not hesitate to contact us if you have any questions or concerns.

Correct-Tech, Inc.

Correct Tech, Inc. - the user friendly control company


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