Eemax Tankless Error Codes: LavAdvantage F0 to F64

By Ray Bennett · Updated 23 October 2026 · 6 min read · Checked against the maker’s manual

Eemax Tankless Error Codes: LavAdvantage F0 to F64

Short answer

Eemax's LavAdvantage manual lists F23 as no heat, F24 as low heat and F38 as high flow. F47 and F48 identify the inlet and outlet temperature sensors. F0 in the current error menu means no errors are present. These meanings come from the LavAdvantage and AccuMix II table in manual EX07200-121 Rev B.

Eemax tankless error codes depend on the heater family: Eemax’s LavAdvantage chart calls F23 no heat, F24 low heat and F38 high flow. The first useful step is to match your heater to that chart before treating a number as a failed part.

This guide uses Eemax manual EX07200-121 Rev B for LavAdvantage models such as SPEX1812T. Its troubleshooting table also covers AccuMix II, while FlowCo has a separate light pattern table. The HomeAdvantage II manual saved for this guide has symptom troubleshooting, not this F-code list.

Our tankless water heater code guide covers gas models. Their ignition and exhaust codes do not explain the electric heaters here.

A Marey ECO150 has a different manual and service boundary. See the Marey water heater code guide rather than borrowing an Eemax meaning.

Before you start

What to carry: a torch, your phone and the heater paperwork. Photograph the complete model number and the display, including any letters. Keep any suffix on the model number when you send it to support.

Gas or electric? These are electric instantaneous water heaters, as Eemax labels them. Leave the cabinet closed while identifying the unit.

Renting? Send the model, code and hot water symptoms to the maintenance contact so they can arrange the right service visit.

The code menu is outside; electrical checks stay with service.
Eemax requires electrical power disconnected before installation, modification or service, and power off before removing the protective cover for any reason. Its voltage fault remedies call for certified personnel to verify the supply.

The chart includes resistance measurements, wiring inspections and voltage measurements while the heater is running. Those are service procedures, not checks to try with a household meter. Keep hands away from hot water if a temperature fault is present.

Find the current error, not just an old one

The LavAdvantage menu separates CE, the current error, from PE, the previous five errors. F0 belongs to the current error screen and means no errors are present.

Check 1Front panel observation without parts or cabinet access

Open the LavAdvantage error menu

Eemax’s operating instructions start at the temperature setpoint. Hold both the plus and minus buttons for three seconds to enter the Advanced menu. From there, hold both buttons for ten seconds to reach Error Codes and Units.

The manual labels current errors CE and past errors PE. PE stores the previous five errors and faults. Pressing minus shows the screen title, and pressing plus for one second moves through the screens.

Read the current entry first, then keep the history separately for support. Eemax says F0 means no errors are currently present. A past entry is useful history, but it should not be described as today’s active fault.

To return from this menu to the setpoint, Eemax says to hold both buttons for ten seconds or let the display return on its own. Leaving the menu is display navigation, not a repair procedure.

The LavAdvantage F-code table

These are the entries in Eemax’s LavAdvantage and AccuMix II table on page 13 of Rev B. The table names possible causes, so the same code can lead to more than one repair.

Code	Eemax’s description	What the chart points toward
F23	No heat	Element, safety cutout, switching components, control board or inlet water conditions
F24	Low heat	Low voltage, switching components, board or temperature sensors
F33	Residual heat	Elevated internal temperature without flow, or both triacs failed closed
F34	Overvoltage	Supply voltage above the heater’s specification
F36	Undervoltage	Supply voltage below the heater’s specification
F38	High flow	Too much flow to reach the temperature setpoint
F47	Inlet thermistor failure	Interrupted or disconnected inlet temperature sensor
F48	Outlet thermistor failure	Interrupted or disconnected outlet temperature sensor
F64	Freeze warning	Inlet temperature below 35 degrees F

When heat is missing or cannot keep up

Check 2Flow adjustment for F38; electrical diagnosis for heat faults

Separate F23 from F24 and F38

For F23, Eemax says heating stops after thirty seconds of a continuous no heat condition. Its possible causes range from the element to the control board. The technician’s first listed remedy is measuring element resistance with the unit completely off.

For F24, Eemax says heating remains enabled with reduced performance. The chart directs service to verify supply voltage while the heater runs. That distinguishes a low heat complaint from a heater that has disabled heating altogether.

For F38, Eemax says the unit operates as intended, but the flow is too high to reach the setpoint. Reduce the hot water flow at the faucet and observe the result. The chart names an outlet flow restrictor or faucet aerator as ways to reduce flow.

If there is no active code and the trouble is confined to one fixture, the tankless water heater problems guide can help organize the symptom before you arrange service.

Check 3Electrical measurements against the heater's rated supply

Treat F34 and F36 as supply checks

Eemax assigns F34 to excessive inlet voltage and F36 to insufficient inlet voltage. For both entries, it calls for certified personnel to verify the supply and provide voltage within the specified range.

Temperature sensing and protective stops

In Eemax's LavAdvantage chart, F47 names the inlet sensor and F48 the outlet sensor. This drawing shows their functions, not their physical positions or wiring.

Check 4Sensor connection and wiring inspection during service

Keep F47 and F48 attached to the right sensor

Eemax describes a thermistor as interrupted or disconnected in both sensor rows. F47 directs service to the inlet sensor connections and wiring; F48 directs it to the outlet sensor.

For F47, the manual says heating can continue using a default inlet temperature, with hotter or cooler outlet water possible. For F48, heating remains enabled but automatic calibration is disabled. Hot water still coming from the tap does not rule out these reports.

Check 5Checking water conditions and the cause of a protective stop

Distinguish residual heat from a freeze warning

For F33, Eemax lists elevated internal temperature without flow and both triacs failed closed as possible causes. Heating stays disabled until outlet temperature falls below the reactivation threshold for the model suffix. Its listed remedy is to run water through the unit.

Keep clear of the discharge while doing that. If F33 continues or returns, service needs to investigate the cause rather than repeatedly using water flow to clear the display.

For F64, Eemax says heating is disabled while the inlet temperature is below 35 degrees F. Its remedy is to raise the inlet water temperature above that threshold. A higher outlet setpoint is not the inlet temperature change the chart requires. Eemax also requires installation where the heater will not be exposed to freezing temperatures. Ask the installer to check the location if freezing is a concern.

What each one takes

Finding	Work involved
F0 in CE	Use the actual water symptom to decide what to investigate
F38	Reduce flow; assess the outlet aerator or flow restriction if needed
F23 or F24	Service diagnosis before choosing an element or control part
F34 or F36	Certified electrical testing and supply correction
F47 or F48	Inspection of the named sensor circuit
Persistent F33 or F64	Investigation of temperature conditions and protection

Questions people ask

Where is the Eemax error codes PDF?

The LavAdvantage, AccuMix II and FlowCo manual gives the menu on page 12 and the F-code chart on page 13. Use revision EX07200-121 Rev B with its listed models.

Is CE another fault?

Eemax uses CE as the current error screen title. It is the menu label beside the information you need, rather than a component diagnosis.

What does PF mean in the Advanced menu?

Eemax calls PF the power factor screen and describes it as how hard the heater is working. FLO is water flow, IN is inlet temperature and OUT is outlet temperature.

Does a FlowCo flashing light use this table?

No. Rev B gives FlowCo a separate LED table. In that table, a solid light means heating and one flash every four seconds means idle.

Can I use these codes for HomeAdvantage II?

The HomeAdvantage II manual used here has its own symptom table. Do not carry the LavAdvantage F-code meanings into that family or Series Three just because the Eemax name matches.

The other electric tankless guides: Stiebel Eltron displays, EcoSmart codes and tankless water problems.

Sources: Eemax LavAdvantage, AccuMix II and FlowCo Installation Guide and Owner's Manual EX07200-121 Rev B, pages 1, 2, 3, 7, 11 and 13; error menu on page 12. Eemax HomeAdvantage II Installation Instructions and Owner's Manual, troubleshooting section