Common symptoms and what to check first, and the control app's alarm list. If the cause is not clear, stop the system and contact HydroXpand.
On this pageWhere to start
Where to start#
- Look at Status and MQTT at the top of the app. If it shows OFFLINE, check power and Ethernet first.
- Read the code of any active alarm on the Alarms & Events screen, find the same code in the Alarms section below and follow the action.
- If there is no alarm, read the inlet and outlet pressures, tower temperatures and dew point on the P&ID screen and compare them with the Find by symptom table.
- If the cause is not clear, stop the system, gather the items under What to send us and contact HydroXpand.
Find by symptom#
Find the symptom in the table below. Dew point, pressure, regeneration temperature and drains are covered cause by cause in symptoms A to D after the table.
| Symptom | Possible cause | What to do |
|---|---|---|
| Outlet dew point too high after start | The adsorbent took up moisture before start-up | Send the product to vent and let the unit complete one or more full cycles |
| Outlet dew point rises during operation | Hydrogen at H2 IN warmer or wetter than usual. Regeneration cycle set too long | Check the upstream units and the room temperature. Check the cycle setting |
| Pressure does not reach 10 barg, or the status shows STANDBY | A leak, or the HXB-V1 units are not producing enough hydrogen. The unit waits when inlet pressure falls below 8.5 barg | Leak-check the connections. Check the HXB-V1 units. The unit carries on automatically once inlet pressure is back at 9.5 barg or above |
| Frequent drain events | More water carried from upstream than usual | Check the HXB-V1 units and the inlet line for water collecting at low points |
| No flow at PURGE during regeneration | Vent line blocked or closed | Stop the system. Clear the vent line. Never fit a valve in it |
| Unit stops with a liquid leak alarm | Liquid has collected inside the unit | Keep it stopped and switched off. Contact HydroXpand |
| Heater does not heat | Overheat trip open, or no power to the heater | Let the unit cool. If it repeats, contact HydroXpand |
| No connection over Ethernet | Cable, network settings | Check the cable and the IP settings on the control PC |
Symptom A. The outlet dew point is too high#
- Just after start-up
- The adsorbent took up moisture while the unit was stored or stopped. Send the product to vent and let the unit complete one or more full cycles. If it is still high after that, work through the items below.
- The incoming hydrogen is warmer or wetter than usual
- Warning WA_08 appears when the adsorber inlet gas temperature exceeds 80 °C. Check the operating temperature of the HXB-V1 units, the room temperature, and whether water is collecting anywhere in the inlet line.
- The regeneration settings have changed
- A longer cycle or a lower regeneration temperature sends the tower back on line less dry. Compare the settings with the defaults under regeneration settings.
- Regeneration is not finishing
- Hydrogen should always leave through PURGE during regeneration. If the PURGE vent is blocked, the water driven off the tower cannot be carried out. Stop the system and clear the vent line. If the tower is not heating, see symptom C.
- Only your own analyser reads high
- The same water content reads as a higher dew point at higher pressure. About 5 ppm of water reads about -65 °C at atmospheric pressure and about -47 °C at 10 barg. First check which pressure your analyser's reading refers to.
Symptom B. Inlet pressure is low or the unit keeps going to STANDBY#
- Not enough hydrogen from the HXB-V1 units
- Below 8.5 barg at the inlet the dryer waits in STANDBY, and it carries on by itself once the pressure is back at 9.5 barg or above. First check that no HXB-V1 is switched off or stopped on an alarm.
- A connection is leaking
- Warning WA_07 appears when the online tower's pressure is low. Leak-check the connections from the HXB-V1 units to H2 IN, and after H2 OUT, with leak detection fluid.
- The pressure reading looks wrong
- If the reading jumps or sticks at one value, suspect the sensor. A reading outside -1 to 30 barg stops the unit with FS_06. Keep it stopped and contact HydroXpand.
- The pressure is too high instead
- Above 15 barg the unit makes an emergency stop (ES_05). Check that the line after H2 OUT and the vents are not blocked and that no valve in them is closed.
Symptom C. The tower does not heat, or switching is late#
- The regeneration temperature is not reached within the heating time
- If the regeneration temperature is not reached by the end of the heating time, the unit stops with FS_09. If the heater gets no power during heating, it is FS_01. Keep the unit stopped and contact HydroXpand.
- The overheat trip has opened
- The overheat trip cuts heater power directly, independently of the controls. Let the unit cool and check again; if it repeats, contact HydroXpand. Warning WA_04 appears if the heater signal drops out 10 times or more in an hour.
- The switching delay (IDLE) lasts a long time
- The towers swap only once the regenerated tower has cooled to 40 °C or below. The tower is cooled by the hydrogen flowing out through PURGE, so a blocked PURGE vent slows cooling. Check the vent line.
- Manual switching is refused
- If the regenerated tower has not cooled yet, or the conditions are not met, the request is refused with warning WA_05. Check the current step and try again after the switching delay.
Symptom D. Frequent drains or a water-related alarm#
- More water is arriving from upstream
- The separator collects water carried with the hydrogen and empties it to DRAIN. If the drain runs more often than usual, check the HXB-V1 units and the low points of the inlet line for collecting water.
- The level stays high
- Warning WA_03 appears when the separator level stays high for ten minutes; WA_02 means the drain valve did not move as commanded. Check the DRAIN line and the liquid trap for blockages.
- Liquid has been detected inside the unit
- This is the emergency stop for a liquid leak (ES_01). Switch off and treat the liquid as alkaline. Do not restart before the cause is found; contact HydroXpand.
Alarms#
Alarms appear on the control app's Alarms & Events screen and in the safety snapshot on the home screen, with the code, the app message, the measured value and the limit. Emergency stops (ES) and fault stops (FS) stop the unit; warnings (WA) keep it running and tell you. Limits in the tables are the default settings.
Emergency stop (ES)#
| App message | Label | Meaning | What to do |
|---|---|---|---|
| Water leak detected in enclosure | ES_01ELS401 | Liquid was detected inside the enclosure | Switch off and treat the liquid as alkaline. Do not restart until the cause is found |
| Heater contactor welded (main contact stuck closed) | ES_02MC401 | The heater contactor is stuck closed and cannot cut heater power | Open the panel breaker and contact HydroXpand |
| Adsorber bed temperature critical high | ES_03TE201/ | A tower is 30 °C or more above the regeneration temperature (250 °C at most) | Let the unit cool and contact HydroXpand. Do not open it while hot |
| System pressure critical high | ES_05PT101PT301 | System pressure is above 15 barg | Stop the HXB-V1 units and check that H2 OUT and the vent lines are not blocked |
Fault stop (FS)#
| App message | Label | Meaning | What to do |
|---|---|---|---|
| Heater not energized - feedback lost | FS_01HTR201HTR202 | The heater is not powered during heating | Keep the unit stopped and contact HydroXpand |
| Heater contactor not energized | FS_02MC401 | The heater contactor does not close | Keep the unit stopped and contact HydroXpand |
| Heater contactor auxiliary contact mismatch | FS_03MC401 | The heater contactor's auxiliary contact does not match | Keep the unit stopped and contact HydroXpand |
| Switching valve feedback mismatch | FS_04SV201A–202B | A switching valve did not move as commanded | Keep the unit stopped and contact HydroXpand |
| Temperature sensor fault | FS_05TE102TE201TE202 | A temperature reading is outside -50–400 °C | Keep the unit stopped and contact HydroXpand |
| Pressure sensor fault | FS_06PT101PT301 | A pressure reading is outside -1–30 barg | Keep the unit stopped and contact HydroXpand |
| Dew point sensor fault | FS_07AT301 | The dew point reading is outside -100–50 °C | Keep the unit stopped and contact HydroXpand |
| Product dew point out of specification (stop) | FS_08AT301 | The outlet dew point has stayed above -65 °C for ten minutes | Send the product to vent. Check the upstream units and the regeneration settings, and contact HydroXpand if it repeats |
| Regeneration failed - target temperature not reached | FS_09TE201/ | The tower did not reach the regeneration temperature within the heating time | Keep the unit stopped and contact HydroXpand |
Warning (WA)#
| App message | Label | Meaning | What to do |
|---|---|---|---|
| Ventilation fan not running | WA_01FAN401–403 | A ventilation fan is not running | Check that the rear air openings are clear. Contact HydroXpand if it persists |
| Drain valve feedback mismatch | WA_02SV101 | The drain valve did not move as commanded | Check that the DRAIN line and the liquid trap are not blocked |
| Separator liquid level high persists | WA_03LS101 | The separator level has stayed high for ten minutes | Check the DRAIN line, the liquid trap and how much water comes from upstream |
| Heater feedback dropping frequently | WA_04HTR201HTR202 | The heater feedback dropped out 10 times or more within an hour | Contact HydroXpand |
| Manual adsorber switch rejected | WA_05 | A manual tower switch was refused because the conditions were not met | Check the current step and try again after the switching delay |
| Product dew point high | WA_06AT301 | The outlet dew point is above -70 °C (early warning) | Watch the dew point trend. If it stays above -65 °C the unit stops with FS_08 |
| Adsorbing tower pressure low | WA_07PS201APS201B | Pressure in the online tower is low | Check the inlet pressure and leak-check the connections |
| Adsorber inlet temperature high | WA_08TE102 | The gas entering the adsorbers is above 80 °C | Check the upstream units, the room temperature and the inlet line |
| Telemetry not received | WA_09 | The control app is not receiving data from the unit | Check the Ethernet cable and the unit's power |
| Heartbeat not received by device | WA_11 | The unit is not receiving the control app's heartbeat | Check that the app is running on the control PC and the network is connected |
What to send us#
- Serial number and firmware version
- When the symptom first appeared, with the operating pressure and dew point at the time
- An export of recent events
- How many HXB-V1 units are connected, and photos of the pipework
What this chapter is based on
- HXD-V1 datasheetPDF · 3.2 MB
- HXD-V1 outline drawingPDF · 368 KB
- First start checklistPDF · 61 KB
- Routine check sheetPDF · 66 KB
- Maintenance logPDF · 49 KB
- HXD-V1 user manualPDF · 2.7 MB
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