Truma AquaGo Problems: No Hot Water and Lockouts
On this page (7 sections)
The Short Answer: A Truma AquaGo is an on-demand LP heater, so it only fires when water flows through it with good 12-volt power and LP pressure. When it runs cold, the usual causes are a bypass valve left in winterize position, low battery voltage, an empty or closed LP supply, weak water flow, or a lockout the heater is reporting with its red fault LED.
How the AquaGo differs from a tank RV heater
Suburban and Atwood heaters keep a few gallons hot in a tank. The AquaGo heats water as it passes through, so anything that cuts flow, voltage, or gas shows up immediately as cold water. It also has electronic freeze protection and a decalcification mode, and both of these can report warnings that look like faults.
If the yellow LED on the interior control flashes twice with a pause, the heater has stored a fault. The red LED under the switch behind the exterior access panel then flashes an eight-step pattern of short and long blinks. Truma flashing light codes explains how to read it.
Common reasons for no hot water
| What happens | Likely cause | What it means |
|---|---|---|
| No flow through the heater at all | Bypass or winterizing valves still set for storage | Not a heater fault |
| Hot briefly, then cold during a shower | Flow too low at a water-saving head, or demand beyond the heater’s output | Truma lists a separate warning for “too high heat power required” |
| Nothing after an LP cylinder change | LP valve closed, cylinder empty, or air in the line | Usually clears once gas reaches the heater; if it keeps failing, it can lock out with “flame not detected” |
| Heater dead or erratic with lights on | Battery voltage low; Truma’s controller flags supply below 10 V | Charge the battery or reduce the load |
| Fault after a cold night | Freezing risk warning, or freeze damage if 12 V was off | Inspect for water in the bay before restarting |
| Slowly less hot over months | Scale in the heat exchanger on hard water | Decalcify per Truma’s procedure |
What you can check safely
- Confirm the coach’s water bypass is set for normal use and that a hot faucet gives steady flow on the pump or city water.
- Check that the LP cylinder valve is open and that the stove or furnace lights.
- Check battery voltage on the coach monitor and that the battery disconnect is on.
- Read the interior control. If the yellow LED shows the fault pattern, note the red LED’s short and long blinks before you switch anything off.
- Reset once by switching the heater off, waiting about five seconds, and switching it on, as Truma’s instructions describe. If the code comes back, leave the heater off and contact a Truma service center.
- If you smell LP at any time, close the cylinder valve, put out flames, and get everyone out of the coach before you call for help.
Freezing and storage
The AquaGo reports a “risk of freezing” warning (W 30) when the temperature inside the appliance falls to a few degrees above freezing. Truma’s advice is to drain the heater completely, or keep it in Eco or Comfort mode, which circulates water. Freeze protection needs 12-volt power, so pulling the battery disconnect while water is still in the heater leaves it unprotected. A heater that froze with water in it can crack inside, and a reset will not fix that. If the bay is wet after a freeze, keep the LP off and have it inspected.
Scale and decalcification
On hard water, a gradual loss of temperature at the same setting usually means scale. The AquaGo has a decalcification mode, and when it finishes it shows warning W 31, “Decalcification finished.” Return the dial or CP plus to Eco or Comfort to clear it. Only use the descaling method and solution described in your AquaGo manual, and make sure the heater is isolated from the fresh tank first. Putting household vinegar through the whole coach plumbing is not the same procedure.
What a technician will look at
If the heater repeatedly reports “flame not detected,” over-temperature switch faults, an exhaust pressure switch fault, or low gas pressure, an RV technician or Truma service center will test the gas supply pressure, the flue fan and exhaust path, ignition and flame sensing, and the safety switches. These are sealed combustion and gas parts. Owners should not open or bypass them.
Frequently Asked Questions
Q: Why does my AquaGo work at the kitchen sink but not in the shower? A: Either the shower’s flow is too low to keep the heater firing, or you are drawing more hot water than it can heat. Truma lists code 29, “too high heat power required,” for the second case. Try a shower head with more flow, or use less hot water at once.
Q: The yellow light is flashing constantly after I descaled. Is it broken? A: Probably not. The heater shows W 31 when decalcification has finished. Switch the control back to Eco or Comfort mode as Truma instructs.
Q: Will a reset fix an AquaGo that froze? A: A reset clears an electronic warning. It cannot repair a cracked exchanger or fitting. If you find water in the bay or under the coach, keep the LP off and have it inspected. For other RV heater types, see the RV water heater troubleshooting hub.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Truma AquaGo operating instructions, Appendix A: error codes (opens in a new tab)Truma AquaGo RV water heaters; flash codes from the red LED on the heater.
- Truma: tech tip, AquaGo error codes (opens in a new tab)Truma AquaGo with analog panel or CP plus control.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
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