Various error codes and messages indicate that a heater may not be working. These codes and messages vary by part manufacturer.
In this case, we’ll discuss Balboa codes and messages, but much of this information can be used for other parts manufacturers.
These are the most common error codes regarding the heater:
• “Sn” Usually indicates issues with the sensors
• “Dr/Dry” Usually indicates that the heater is dry
• “Fl/FLO” Usually indicates that the water flow is minimal and not sufficient for heating
1. For the first “Sn” we will check the sensors on the hot tub, for this it is important to POWER OFF the spa at the breaker
2. Set your meter to Ohms “Ω” to 20K
3. Remove the wires from the PC board
4. Put your probes one on each wire end (red & black)
5. You reading should be based off of the manufacture’s chart view chart below ↓
“Dry”/ “Dr”
As we stated earlier, is an indication that the heater is dry, this means that there is no water going through the heater,
For this please physically check that there is water going through the heater.
“Flo”
There are several reasons why there could be low water flow, the main one being an obstructed pipe, so be sure to check this. The other could be a dirty filter, which would cause low water flow as it filters slower. In this case, be sure to clean the filter. Also, ask the customer when the last filter was replaced. It is recommended to replace filters every 18 months and wash them every 6 months.
In some applications you will find that the pipe feeding the heater is smaller, for example, a 1” pipe going into the 2” heater, in this case, we recommend using a “Strap around” heater sensor 30674 which can place on the heater and connect in the same area as the regular sensors
Other Issues.
Another issue that can be presented on the heaters is that they are not receiving any voltage, or amperage. Keep in mind that sometimes you can be receiving the proper voltage, but not any amperage or the improper amperage.
How do we check these things?
NOTE: This is to be tested with the power on
Voltage: For voltage, we can test the voltage directly on the heater terminals, with one lead on each terminal. Your reading should be close to your setup (120V or 240V)
note this can be ± 10V from the incoming voltage.
Now for amperage, we recommend testing this with an amp clamp. Grab one of the hot wires on the heater and place in the clamp, separated from the other wire(s), your amp reading should be 16-18 amps (for 230V settings on 4.0kW heaters) or 20-23 amps (For 230V settings on 5.5Kw heaters)
One more thing to test would be the heater terminal on the board, you can unplug the heater (in the case of plug-ins) and then test the center to hot, and center to hot, you should be receiving 120V on each test, if this is not the case, you will have to replace the board.
Author: David Gomez
