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Hydrotherapy units · HydraTherm family

Richmar HydraTherm 3100: troubleshooting and error codes

The ServiceForge knowledge base holds 20 documented symptoms for the Richmar HydraTherm 3100, with 68 ranked causes, 7 diagnostic checks with test points and expected values, and 0 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Both lamps illuminated but unit does not heat patient safety

Power and display lamps are on but no heating occurs; LOW WATER status may be shown.

Ranked causes

  1. 1. Low water level (common)
  2. 2. Dirty or contaminated temperature sensor housing (common)
  3. 3. Issue with digital thermostat (occasional)
  4. 4. Faulty heating element (occasional)
  5. 5. Faulty heating element contactor/relay (occasional)

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Pump does not activate in drain mode caution

Power lamp illuminated and switch in drain position but pump does not energize.

Ranked causes

  1. 1. Pump electrical connection loose or disconnected (common)
  2. 2. Pump 2 Amp protection fuse open (common)
  3. 3. Pump faulty (occasional)
  4. 4. 12 VDC power supply faulty (occasional)
  5. 5. Heat/Drain switch faulty (occasional)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Pump does not energize caution

Pump does not come ON when drain mode switch is set to drain position

Ranked causes

  1. 1. Loose electrical connection to 3-position receptacle (common)
  2. 2. Pump protection fuse is open (occasional)
  3. 3. Pump is faulty (occasional)
  4. 4. 12VDC power supply is faulty (rare)
  5. 5. HEAT/DRAIN switch is faulty (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit fails to power in drain mode; no lamps illuminated caution

Unit does not respond to power switch when in drain mode; neither power lamp nor display illuminates.

Ranked causes

  1. 1. MAINS fuse(s) open (common)
  2. 2. Facility outlet/receptacle not powered (common)
  3. 3. Faulty power cord (occasional)
  4. 4. Faulty power switch (occasional)
  5. 5. Defective power indication lamp (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit fails to power on caution

Power indication lamp and digital thermostat display do not illuminate

Ranked causes

  1. 1. Mains fuse open (common)
  2. 2. Facility outlet not powered (common)
  3. 3. Power cord faulty (occasional)
  4. 4. Power switch faulty (occasional)
  5. 5. Power indication lamp defective (rare)

5 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit does not heat caution

Both lamps illuminate but unit does not heat. LOW WATER status may be illuminated on controller display.

Ranked causes

  1. 1. Low water level or contamination on temperature sensor (common)
  2. 2. Issue with Digital Thermostat (occasional)
  3. 3. Faulty Heating Element (occasional)
  4. 4. Faulty Heating Element Power Contactor/Relay (occasional)
First check

Check LOW WATER status on Digital Thermostat Controller Display

Test point
Controller display
Expected
LOW WATER indicated or not indicated

1 more check with pass and fail actions, 5 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit does not power on high voltage

Power Indication Lamp does not illuminate

Ranked causes

  1. 1. Fuse(s) open (common)
  2. 2. Facility outlet not powered (common)
  3. 3. Faulty Power Cord (occasional)
  4. 4. Faulty Power Switch (occasional)
First check

Check MAINS fuse(s) for continuity

Test point
MAINS fuse(s)
Expected
Continuity
Tools
OHM Meter

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit fails to power on; power lamp dark caution

No power indication lamp illumination; unit does not respond to power switch.

Ranked causes

  1. 1. Fuse(s) open (common)
  2. 2. Facility outlet not powered (common)
  3. 3. Faulty power cord (occasional)
  4. 4. Faulty power switch (occasional)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit heats beyond desired temperature patient safety

Both lamps illuminated but unit heats well beyond setpoint; unable to limit maximum temperature.

Ranked causes

  1. 1. Setpoint setting incorrect (common)
  2. 2. Temperature offset setting incorrect (occasional)
  3. 3. Digital thermostat controller faulty (occasional)
  4. 4. Power contactor faulty (occasional)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit heats beyond setpoint caution

Power and display illuminated; unit heating to temperatures well beyond desired setpoint

Ranked causes

  1. 1. Setpoint setting incorrect (common)
  2. 2. Temperature offset setting incorrect (occasional)
  3. 3. Digital thermostat controller faulty (rare)
  4. 4. Power contactor faulty (rare)

4 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Controller displays "---" or "ooo" caution

Both lamps illuminated but digital controller shows "---" or "ooo" characters instead of temperature.

Ranked causes

  1. 1. Thermistor wire disconnected at controller terminal (common)
  2. 2. Faulty HIGH LIMIT/Thermistor Assembly (occasional)
  3. 3. Faulty digital controller (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Digital thermostat display shows dashes or zeros caution

Power and display illuminated; controller displays '---' or 'ooo'

Ranked causes

  1. 1. Thermistor wire disconnected at controller (common)
  2. 2. Faulty high limit/thermistor assembly (occasional)
  3. 3. Digital controller faulty (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power lamp illuminates but thermostat display dark caution

Power indication lamp is on but digital thermostat controller display does not illuminate.

Ranked causes

  1. 1. Heat/Drain switch in drain mode (common)
  2. 2. 24 VAC low voltage fuse open (occasional)
  3. 3. Defective digital thermostat control (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power lamp on, thermostat display off

Power Indication Lamp illuminates but Digital Thermostat Controller display does not illuminate

Ranked causes

  1. 1. HEAT/DRAIN Switch in DRAIN MODE (common)
  2. 2. 24VAC Low Voltage Fuse open (occasional)
  3. 3. Defective Digital Thermostat Control (occasional)
First check

Verify HEAT/DRAIN Switch position

Test point
HEAT/DRAIN Switch
Expected
HEAT position

1 more check with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Pump energized but no water flowing caution

Pump motor runs but no water flows through system in drain mode

Ranked causes

  1. 1. Shut off valve is closed (common)
  2. 2. Drain hose is kinked or obstructed (common)
  3. 3. Pump is faulty (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Pump energized but no water flows in drain mode caution

Pump activates and runs but water does not flow through system during drain operation.

Ranked causes

  1. 1. Shut-off valve closed (common)
  2. 2. Drain hose kinked (common)
  3. 3. Pump faulty (occasional)

3 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Unit heats then stops, does not reach setpoint caution

Both lamps illuminate. Unit starts heating then stops before reaching desired temperature or setpoint.

Ranked causes

  1. 1. Incorrect SETPOINT setting (common)
  2. 2. Digital Thermostat Controller issue (occasional)
First check

Verify SETPOINT setting/value

Test point
Digital Thermostat Controller
Expected
Setpoint matches desired temperature per manual

6 corrective actions and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power lamp dark but thermostat display illuminates caution

Digital thermostat controller display is on but power indication lamp does not illuminate.

Ranked causes

  1. 1. Power indication lamp faulty (occasional)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power lamp illuminated but display not illuminated in drain mode

Power indication lamp is on; digital thermostat display is dark during drain mode operation

Ranked causes

  1. 1. Normal operation in drain mode (common)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Power lamp off, thermostat display on

Power Indication Lamp does not illuminate but Digital Thermostat Controller display is illuminated

Ranked causes

  1. 1. Power Indication Lamp faulty (common)
First check

Verify unit/device is operating properly

Test point
Unit operation
Expected
Unit operates normally

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.