If you have a Truma AquaGo hot water heater installed in your RV, you may have experienced quick double-flashing yellow light in your LED3 control switch. It's a catch-all alert and, while it is flashing, the red LED flashing sequence at the unit itself needs to be read and decoded. During winter, this happens in our RV every time a significant amount of water is passed through the unit - typically when showering. Thankfully, even in this situation, the temperature on full flow is just comfortable enough for a nice shower - frankly, I wouldn't shower any hotter anyway... Still, I like to get to the bottom of these things to make sure that no damage is being done.
To set the scene, we spend the winter in Whistler BC, which gets very cold, and the double-flashing LED3 appeared every time someone had a shower or used a lot of water in the kitchen. We observed that when first turning the shower on, the unit would deliver fully hot water at 49degsC, but it would then drop slightly for a little while and then drop further and remain at this temperature, even with the fact turned fully to hot - this was a critical observation as it turned out... I'll come back to this.
On checking, it turns out the cause is the same every time: error code #29 - according to the manual the error is: 'Too high heat power required" and the explanatory description reads: "You are trying to to use more hot water than the appliance can supply."
After unsuccessfully going through all rectification steps suggested in the manual, I contacted Truma to get to the bottom of the cause for this because things didn't make sense to me. Specifically, our water flow rate was relatively low, so I didn't think that we were overtaxing the system. IOW, we were not sending water through the unit at a rate which did not allow the unit to heat the water quickly enough. Lengthy exchanges with the Truma technician ensued, and I thought I should share what transpired to save anyone else having to go through the troubleshooting.
Some basics: the flow rate in our shower at the site (at the time) was 5.2 liters/minute (sorry abt the metric, but I'm in Canada...). Truma confirmed that the maximum flow rate the AquaGo can handle is 7.5 L/min, therefore I could immediately eliminate an excessive flow rate as the cause - we were clearly not asking more of the unit than it can deliver volume-wise.
After a bit more thinking it occurred to me that "You are trying to to use more hot water than the appliance can supply." may, in fact not just be a volume/flow issue but also one of temperature differential issue. What led me to that idea is the observation of the stepped temperature drops I mentioned earlier: the initial full 49degsC delivery was the liter or so of constantly hot water in the AquaGo's reservoir and the following slight drop was the volume of water held in our heated water hose. When that had flowed through the unit, the temperature dropped to its final and continuous level, as it was receiving the water at the ambient temperature delivered by the utility pole faucet bringing water into the RV. This water temperature was a few degrees above freezing. So, clearly, the performance of the unit was significantly affected by the temperature of the incoming water - which makes sense.
Put simply, error code 29 can also be triggered if the water received by the unit is so cold that it cannot heat it to 49degsC in the time it has as the water passes through the heat element, even at a reduced flow rate (as is the case with our RV where it is only about 2/3 of the maximum flow rate). Truma confirmed to me that his in fact the case. Unfortunately, the manual doesn't mention this. There was nothing to suggest that any damage can be done to the unit by its use despite the flashing LED3. This is more of an advisory warning than a "red alert" warming.
The proof point is the arrival of spring: now that the temperatures remain well above the freezing point and the ambient water temperature has consequently risen a bit, the double-flashing and error code 29 has all but stopped - because the temperature differential between the incoming water and 49degsC is now a lot less. It very occasionally still happens - I suspect during the colder periods we still get during spring, although I have not paid it any attention, to be honest. I fully expect that we will not see the error code during summer.
Final comments: (1) The issue could obviously be somewhat alleviated by not opening the tap fully and thereby slowing the flow rate in the unit, however the 5.1L/min is about as low a flow as we would tolerate for a shower. If an RV site delivered water at, say 6 or 7 L/min, then the temperature might drop below a comfortable level and we could then close the tap a little to slow the flow rate to the 5L/min and expect to get what we are getting now. (2) Despite the above vagaries, we love our Truma AquaGo and wouldn't go back to a conventional tank-based hot water system. As I said, even on the coldest days (minus 27degsC) the Truma delivered water at a temperature allowing for a very comfortable shower at an acceptable 5.2L/min.
To set the scene, we spend the winter in Whistler BC, which gets very cold, and the double-flashing LED3 appeared every time someone had a shower or used a lot of water in the kitchen. We observed that when first turning the shower on, the unit would deliver fully hot water at 49degsC, but it would then drop slightly for a little while and then drop further and remain at this temperature, even with the fact turned fully to hot - this was a critical observation as it turned out... I'll come back to this.
On checking, it turns out the cause is the same every time: error code #29 - according to the manual the error is: 'Too high heat power required" and the explanatory description reads: "You are trying to to use more hot water than the appliance can supply."
After unsuccessfully going through all rectification steps suggested in the manual, I contacted Truma to get to the bottom of the cause for this because things didn't make sense to me. Specifically, our water flow rate was relatively low, so I didn't think that we were overtaxing the system. IOW, we were not sending water through the unit at a rate which did not allow the unit to heat the water quickly enough. Lengthy exchanges with the Truma technician ensued, and I thought I should share what transpired to save anyone else having to go through the troubleshooting.
Some basics: the flow rate in our shower at the site (at the time) was 5.2 liters/minute (sorry abt the metric, but I'm in Canada...). Truma confirmed that the maximum flow rate the AquaGo can handle is 7.5 L/min, therefore I could immediately eliminate an excessive flow rate as the cause - we were clearly not asking more of the unit than it can deliver volume-wise.
After a bit more thinking it occurred to me that "You are trying to to use more hot water than the appliance can supply." may, in fact not just be a volume/flow issue but also one of temperature differential issue. What led me to that idea is the observation of the stepped temperature drops I mentioned earlier: the initial full 49degsC delivery was the liter or so of constantly hot water in the AquaGo's reservoir and the following slight drop was the volume of water held in our heated water hose. When that had flowed through the unit, the temperature dropped to its final and continuous level, as it was receiving the water at the ambient temperature delivered by the utility pole faucet bringing water into the RV. This water temperature was a few degrees above freezing. So, clearly, the performance of the unit was significantly affected by the temperature of the incoming water - which makes sense.
Put simply, error code 29 can also be triggered if the water received by the unit is so cold that it cannot heat it to 49degsC in the time it has as the water passes through the heat element, even at a reduced flow rate (as is the case with our RV where it is only about 2/3 of the maximum flow rate). Truma confirmed to me that his in fact the case. Unfortunately, the manual doesn't mention this. There was nothing to suggest that any damage can be done to the unit by its use despite the flashing LED3. This is more of an advisory warning than a "red alert" warming.
The proof point is the arrival of spring: now that the temperatures remain well above the freezing point and the ambient water temperature has consequently risen a bit, the double-flashing and error code 29 has all but stopped - because the temperature differential between the incoming water and 49degsC is now a lot less. It very occasionally still happens - I suspect during the colder periods we still get during spring, although I have not paid it any attention, to be honest. I fully expect that we will not see the error code during summer.
Final comments: (1) The issue could obviously be somewhat alleviated by not opening the tap fully and thereby slowing the flow rate in the unit, however the 5.1L/min is about as low a flow as we would tolerate for a shower. If an RV site delivered water at, say 6 or 7 L/min, then the temperature might drop below a comfortable level and we could then close the tap a little to slow the flow rate to the 5L/min and expect to get what we are getting now. (2) Despite the above vagaries, we love our Truma AquaGo and wouldn't go back to a conventional tank-based hot water system. As I said, even on the coldest days (minus 27degsC) the Truma delivered water at a temperature allowing for a very comfortable shower at an acceptable 5.2L/min.
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