Short answer
The Hamworthy Dorchester DR-FC Evo water heater shows letter-and-number codes. S codes mostly relate to sensors that are not connected or damaged; other codes cover ignition, flame and control faults. The full list from Hamworthy is below.
Water heaters work harder than boilers
A commercial direct-fired water heater in a hotel, gym or kitchen may fire hundreds of times a day. Scale, sludge in the tank and condensate problems cause many repeat faults, so descaling and anode checks at service matter as much as burner work.
Before you reset
A single reset after a power cut or a known one-off event is reasonable. Repeated resets are not: many commercial controls count resets and lock out further (for example a 'too many resets' code), and resetting a flame or gas valve fault over and over can mask a dangerous condition. If a lockout returns, isolate the appliance and call a Gas Safe registered engineer with the relevant commercial competence.
Hamworthy Dorchester DR-FC Evo fault codes
| Code | Meaning | What to check |
|---|---|---|
| S01 | Sensor is not (correctly) connected | Connect the sensor lead to JP3. Cause: Damaged cable and/or defective sensor. Action: Replace the cable and/or sensor. |
| S02 | Sensor is not (correctly) connected | Connect the sensor lead to JP5. Cause: Damaged cable and/or defective sensor. Action: Damaged cable and/or defective sensor. |
| S03 | Sensor is not (correctly) connected | Connect the sensor lead to JP5. Cause: Damaged cable and/or defective sensor. Action: Replace the cable and/or sensor. |
| S04 | Dummy is not (correctly) connected | Connect the dummy sensor (dummy sensor 1 and 2) leads to JP4. Cause: Defective dummy. Action: Replace the dummy sensor. |
| S05 | Dummy is not (correctly) connected | Connect the dummy sensor (dummy sensor 1 and 2) leads to JP4. Cause: Defective dummy. Action: Replace the dummy sensor. |
| S11 | Short circuit in sensor circuit | Replace the cable and/or sensor. |
| S12 | Short circuit in sensor circuit | Replace the cable and/or sensor. |
| S13 | Short circuit in sensor circuit | Replace the cable and/or sensor. |
| S14 | Short circuit in sensor circuit | Replace the dummy sensor. |
| S15 | Short circuit in sensor circuit | Replace the dummy sensor. |
| F01 | Live and neutral connected wrong way around | Be sure to connect the live and neutral correctly (3.10 Electrical connection in the installation manual). The water heater is phase-sensitive. Cause: Condensation on the flame probe. Action: 1. Disconnect the lead at the flame probe. 2. Ignite the water heater three times. 3. Reconnect the ionisation lead to the flame probe. 4. Ignite the water heater again. 5. The repeated ignition attempts will have caused the condensation to evaporate. Cause: Floating neutral. Action: Install an isolating transformer. |
| F02 | Because of a drop in the supply voltage the fan will not run at the correct speed | 1. Check the supply voltage this must be 230VAC (-15% +10%) 2. Reset controller |
| F03 | Damaged wiring/Open circuit | 1. Check the wiring between the pressure switch and the controller. 2. If necessary replace the wiring |
| F04 | No gas | 1. Open the main gas supply valve and/or the manual gas supply valve before the gas control valve. 2. Check supply pressure to the gas control valve. 3. If necessary Cause: Air in the gas pipes. Action: Bleed the air out of the gas pipe. Cause: Defect in the hot surface igniter circuit. Action: 1. Check that the hot surface igniter is correctly connected (JP2). 2. Check the wiring of the hot surface igniter. 3. Measure the resistance across the hot surface igniter. This must lie between 2 and 10 Ohm (at room temperature). 4. Check that the hot surface igniter lights up during ignition. 5. If necessary replace the hot surface igniter. Cause: Defect in the ionisation circuit. Action: 1. Check that the flame probe is correctly connected (JP2). 2. Check the wiring of the flame probe. 3. Measure the ionisation current. This must be a minimum of 1.5microA. 4. If necessary replace the wiring. Cause: Supply voltage too low. Action: Check the supply voltage |
| F05 | Incorrect roof or wall flue terminal. Recirculating flue gases | 1. Check that the correct roof or wall flue terminal has been installed. 2. If necessary install the correct roof or wall flue terminal. 3. Check that the roof or wall flue terminal discharges into a permitted area. |
| F06 | Damaged cable in contact with metal surface or bent flame probe | Check the wiring and the flame probe. Replace the wiring and/or flame probe if necessary. Cause: Ceramic part of the flame probe is broken/cracked. Action: 1. Check whether the ceramic part of the flame probe is still intact. 2. If not the flame probe must be replaced. |
| F07 | Defective gas control valves | 1. Check whether there is still burner pressure present after the gas control valves have closed. 2. Check whether a flame is still present after the gas control valves have closed. 3. If this is the case the gas control valve must be replaced. |
| F08 | Flame detection before the gas control valve opened | 1. Reset controller. 2. If the error appears again |
| F09 | Temperature at the top of the tank exceeds 93°C | 1. Check that the circulation pump (if present) is working. 2. Check the position of temperature sensor T1. 3. Reset controller. |
| F11 | Defective gas control valves | 1. Check whether there is still burner pressure present after the gas control valves have closed.. 2. Check whether a flame is still present after the gas control valves have closed.. 3. If this is the case the gas control valve must be replaced. |
| F19 | There is not enough supply voltage | 1. Check that there is power to the controller. Cause: There is not enough supply voltage. Action: 2. The measured voltage must be 230 VAC (-15% +10%). |
| C02 | Incorrect reference voltage from the AD converter | 1. Reset controller. 2. Check that the frequency of the power supply is compliant (3.4.2 "General and electrical specifications" in installation manual). If not contact your installation engineer. 3. If the frequency is correct but the error persists replace the controller. |
| C03 | Too many resets in too short a period | Wait for the error to disappear (maximum 1 hour). If the error does not disappear replace the water heater controller. |
| C04 | Incorrect water heater selection/Incorrect selection resistor | 1. Check whether the correct water heater is selected (12.5"Display the selected water heater" in installation manual). 2. If the correct water heater is selected fit the correct selection resistor. 3. If incorrect water heater selected select the correct one. |
| E01 | The temperature of the water at the top of the tank is >85°C | None. This is a temporary message that may appear from time to time but will disappear automatically. |
| E03 | The two temperature sensors in the tank detect a difference of >10°C over a period of at least 60 seconds | 1. Check sensor position and wiring. 2. Reset the controller if necessary. Replace the sensor if the error persists. |
| E04 | The two temperature sensors detect a difference of >10°C over a period of at least 60 seconds | 1. Check the wiring of the dummy1 and dummy2. 2. Reset the controller if necessary. Replace the dummy sensor if the error persists. |
Source: Hamworthy Heating — fault code tool. Codes and meanings can differ between versions and control software — always check the manual for your exact appliance.
Figures are typical for UK natural gas. The current edition of the relevant IGEM standard and the manufacturer's instructions always take precedence on site.
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