Jacuzzi J-355 Topside Blinking Between Flo, Cool And Temp.

[aaronkr]

I have a 2003 Jacuzzi hot tub, model J-355 and it will not heat up past 81 deg. F

The topside control panel continuosly flashes between FLO, Cool and the temperature. I replaced the flow switch after reading articles about FLO errors. After replacing the flow switch, I continue to get the same error message. I have checked the filters and cleaned them out. There is enough water in the tub and both pumps are running.

Could the heater need replaced? Or what else could be causing the error message.

[Spa_Guru]

81 degrees means you aren't heating at all.

1) Remove the filters and see if the flo message goes away.

If yes ---> Get new filters. If no ---> you probably need a pressure switch adjustment or a new pressure switch.

Counter clockwise on the knob will reduce the amount of pressure needed to allow the heater to come on.

[n1oty]

The J-355 does not have a pressure switch. It has a flow switch and it has no adjustment (other than being sure the switch is not installed backwards). Check for proper water flow through the circ pump and heater. Water flow can generally be observed through the clear body of the flow switch.

John

[aaronkr]

Thank you for the advice Spa_Guru, but like John said, this tub doesn't have a pressure switch. It only has a flow switch and I just replaced it. I also took the filters out of the tub and it was still giving me the same FLO, COOL, 81 message. I can see the water running through the clear fitting where the flow switch is installed. Is it possible that the heater needs to be replaced, or would that not be an option in this case? If not, what would the next recommended steps be to properly diagnose the problem. Thank you again for your feedback.

[Roger]

I would check to make sure you have the proper flow. Could be the circ pump is getting weak.

[Spa_Guru]

The core problem is flow, or the detection of flow. No flow causes the heater to shut down for safety reasons.

[n1oty]

Disconnect the pressure switch connector from the circuit board with the tub powered down. Ohm out the two switch wires. There should be NO continuity. Power up the tub with the connector still off of the board. Once you observe the water flow and see the metal stem pressing against the vertical plastic stem in the pressure switch, ohm out the switch. If you have continuity now, the switch is good. Your problem must be with the board, although I personally like to take a circuit board jumper and jumper across the two board terminals for the flow switch to see if that energizes the heat circuit. Finally, if you have continuity (50 ohms or less) both powered and unpowered, the flow switch is bad, but you can test the rest of the heater circuit by fooling the board. To do this, power up the tub with the flow switch disconnected from the board. Power up the tub, wait for good flow through the flow switch, then re-attach the connector to the board

John

[Spa_Guru]

The issue with jumping the flow switch circuit is if the flow, in spite of your observations, is not what it should be, then you get heater damage.

[aaronkr]

John,

Thank you for the advice. I will test the connections of the flow switch and try the procedure you recommended. I just replaced the flow switch about a week ago. Is it possible I could have received a bad flow switch, or when inserting the flow switch into the T, can you make it too tight or doesn't that have an affect on it.

Again, I appreciate everyones feedback and support with this matter. I just can't wait to get the problem solved.

Thank you

[Spa_Guru]

When threading the flow switch in you can get it in backwards. make certain it is correctly oriented.

[n1oty]

The issue with jumping the flow switch circuit is if the flow, in spite of your observations, is not what it should be, then you get heater damage.

The J-355 utilizes a Harwil flow switch that requires in excess of 8 to 9 GPM in order to push the magnet against the reed switch stem. If that is observed through the clear plastic body, there is no way that the heater can be energized without sufficient flow to prevent element damage.

John

[n1oty]

The issue with jumping the flow switch circuit is if the flow, in spite of your observations, is not what it should be, then you get heater damage.

The J-355 utilizes a Harwil flow switch that requires in excess of 8 to 9 GPM in order to push the magnet against the reed switch stem. If that is observed through the clear plastic body, there is no way that the heater can be energized without sufficient flow to prevent element damage.

John

John,

Thank you for the advice. I will test the connections of the flow switch and try the procedure you recommended. I just replaced the flow switch about a week ago. Is it possible I could have received a bad flow switch, or when inserting the flow switch into the T, can you make it too tight or doesn't that have an affect on it.

Again, I appreciate everyones feedback and support with this matter. I just can't wait to get the problem solved.

Thank you

Jacuzzi flow switches come with the flow switch already installed in a new clear plastic body. There is no need to unthread your old switch in order to thread in the new switch. You can either damage the switch this way or screw up the orientation of the switch which is critical. It is better to unclamp the hoses, remove the old assembly, replace it with the new assembly and reclamp. A further benefit to changing the entire assembly is that the plastic body can become brittle with age and over-threading a new switch can crack the body. A common rookie mistake is to overtighten and/or disorient the flow direction. There are arrows on the switch as well as the body that indicate proper flow direction.

John

[aaronkr]

I was able to adjust the flow switch and it started working. Again, thank you for all of the advice everyone has provided.