Truma Aqua Go filter failed

[Patriot]

This morning while doing a full systems ‘go’ inspection on Hull #634 XPLOR, I discovered when I configured the Truma water heater valve to the ON position, an impressive stream of water shot directly out of the Truma filter exterior housing. After a little troubleshooting, I removed the filter and discovered that inside the filter housing, a small black round piece of plastic had blown out of the filter housing. This rendered the filter useless. We have had 5.5 years of trouble-free service from our tankless Truma and this was a first. We like our Aqua Go.

I am posting this in the event anyone should have the same issue with their Truma filter. I have the optional antifreeze filter which works in a pinch as a back up. If you do not have the optional antifreeze filter as a back up, you will be stuck like Chuck with no hot water. In order for the Aqua Go to work, it has to have the filter element.

I contacted Oliver Service and ordered a OEM replacement and an extra back filter up of the exact one you see in the below pics. “Two is one and one is none.” 🫡🇺🇸

Replacement filters are $95.00 plus shipping. Thank you Mike Sharpe for getting my new filters shipped out. 

 

The tiny piece of plastic that broke loose. 

Here is the filter that failed. You should not be able to look through your filter. The arrow points to where  this tiny piece blew out. There is no way to repair it. 

I pass this on, so that if you have this issue you can just replace the filter with a new one.

 

Edited yesterday at 09:19 PM by Patriot

[Galway Girl]

Part number of OEM Filter is 
AquaGo Replacement Filter # 77000-00251

[Rolind]

Thanks I will keep an eye on mine!

 

[DunnYet]

Thanks very much @Patriot for this. It makes me wonder - I generally leave the “heater” filter in all the time regardless of season. Should I pull it for the “off season” and only put it in during the cold camping months? I only switch to the standard filter when running the decalcification cycle. Am I doing this wrong?

[Ollie-Haus]

Thanks for sharing David, I just purchased a backup on Ebay for $25. 
 

If anyone needs a replacement or spare and can’t find one on the cheap, they are available on Amazon as well. 
https://a.co/d/00C38npm

Edited 21 hours ago by Ollie-Haus

[Patriot]

7 hours ago, DunnYet said:

Thanks very much @Patriot for this. It makes me wonder - I generally leave the “heater” filter in all the time regardless of season. Should I pull it for the “off season” and only put it in during the cold camping months? I only switch to the standard filter when running the decalcification cycle. Am I doing this wrong?

@DunnYet 
Open source -
No, you should not leave the Truma winterization (bypass) filter or standard stainless steel filter installed all season long. [1]

If you are actively using your RV during the camping season, you should be using the standard stainless steel filter (or the Truma Electric Antifreeze Kit if actively in use). The official winterization plug/filter is strictly designed to replace the standard filter for winter storage and is not meant to be run full-time. 

Keep these quick winterization rules in mind:

• For Winter Storage: Drain your Truma system and remove the filter cartridge entirely. Store the filter in a dry place inside your RV and leave the yellow Easy Drain Lever closed. Leaving any filter inside during freezing weather can trap water, expand, and permanently damage the unit. [1, 2, 3]
• For Active Winter Camping: If you plan to travel in freezing temperatures, you can use the Truma Electric Antifreeze Kit. This specific kit can be installed in place of your standard filter to keep the water heater from freezing without draining your propane. [1, 2]
• For Normal Summer Use: Remove the winterization plug and reinstall your standard stainless steel mesh filter before de-winterizing and turning your water system on for regular use.

Edited 15 hours ago by Patriot

[Ollie-Haus]

Here's just a little insight into what likely happened in David's situation and how to reduce the chances of others experiencing the same situation in the future.

After examining this filter plug more closely, I have determined that the part that broke out of David's filter is designed as an over pressure protection for the water heater. By code all water heaters are required to have a high pressure relief. For the Truma, instead of a standard pressure relief valve, they have chosen to use a sacrificial relief that's designed to let an over-pressure situation release and drain to the outside. 

With David's description of the event, I'm convinced that when the water supply valve at the water heater was opened to run through the water heater, a high pressure surge hit the water heater causing the "safety device" to rupture. This was very likely a high water pressure situation, possibly caused by and air pocket in the water line just before the valve that caused a water hammer effect in the heater when the valve was opened. 

Now I can't prove this is what actually happened, but in liquid and steam systems I have worked with over the years, coils such as that in the Truma water heater are usually protected by what is called a rupture disc, designed to fail before damage can occur to the more valuable parts of the system. Whenever opening a valve to pressurize a system, it's imperative to open the valve very slowly so as not to cause a hydraulic hammering of the system when doing so. Also it's very important to run a system clear of any air pockets before opening a valve to other components in the system. For air and gas systems this is not an issue. But with hydraulic systems it's critical. 

A very good precautionary step to reduce the chances of water hammer when opening a valve is to very slowly open the valve to prevent a surge. One additional precautionary step to take before repressurizing the water heater is to open one of the faucets to hot water to allow flow through that side of the system when the valve to the is being opened to the water heater. Again this allows flow through the water heater, allowing air pockets to escape without cause a water hammer condition. These steps should prevent this from occurring to anyone in the future. 

Hope this helps anyone with concerns about their Truma water heater.

PS - Obviously a high water pressure from the utility source connected to the trailer could also cause this situation to happen. This is the obvious reason why we must always use a pressure regulator and never setting it above 40 psi. 

PPS - If you purchased the Truma anti-freeze plug when you bought your Oliver, it can be used in place of the regular filter plug should you need a short term backup. It works exactly the same as the standard filter plug, just has a heat coil built into it. You don't need to plug the coil in for this use purpose. 

[DanielBoondock]

3 hours ago, Ollie-Haus said:

After examining this filter plug more closely, I have determined that the part that broke out of David's filter is designed as an over pressure protection for the water heater. By code all water heaters are required to have a high pressure relief. For the Truma, instead of a standard pressure relief valve, they have chosen to use a sacrificial relief that's designed to let an over-pressure situation release and drain to the outside. 

Great comments thanks. This part is interesting because it does have a standard over pressure valve just above the filter housing. Do older Trumas not have this?

Otherwise great tip about the antifreeze unit, I had it in there full time 

[Ollie-Haus]

47 minutes ago, DanielBoondock said:

Great comments thanks. This part is interesting because it does have a standard over pressure valve just above the filter housing. Do older Trumas not have this?

Otherwise great tip about the antifreeze unit, I had it in there full time 

Too funny! I was standing up when I looked under the cover plate and my relief valve lever was turned upwards where I couldn’t see it. Kind of like me looking for the ketchup in the fridge I guess. 😉

Looks like they have the typical water heater relief setup after all. 

Nevertheless when you look into the open end of the filter, you can see it’s designed with a much thinner wall around the back of the plastic housing, very similar to a rupture disc. Again I don’t know first hand if that’s actually Truma’s design intention, but with an overpressure situation this would be a weak point that would likely fail. And it would fail through the drain port of the water heater as you would expect if that was their intention. Anyway, take it for what it’s worth. 

[Patriot]

Lesson learned.

So after a little deeper dive into cause and effect of how my water filter failed, I learned the following. Last fall when we winterized, I turned off the water supply to the Truma. I went out and pulled the yellow lever down, pulled the filter out and drained all of the water out of the Truma tank. With the system and the tank drained, I reinserted (error on my part) the Truma filter and it must have had a tiny amount of residual water near the internal plastic sacrificial disk inside the filter which resulted in it freezing and then cracking.

If I had completely removed the filter and stored it inside the Oliver as I have done for the past 5 yrs, I likely would not be needing a replacement filter. Important to note, the Truma tank system was completely void of water with exception of what residual was in the filter housing which was apparently just enough to cause the sacrificial disk to do what it is suppose to do…fail.

To complete my inspection of the Truma hot water tank, I temporarily used my winterization filter and the system worked as designed. We had the system set at 120d within about 8-10 seconds we had unlimited hot water in the galley and shower. 

Here is what I learned -open source-

If your Truma AquaGo filter (or Easy Drain Lever) blew out, gushing water from the housing, the internal plastic disc or O-rings likely failed. This is almost always caused by residual water freezing and expanding inside the housing, or the O-rings being misaligned. [1, 2, 3, 4]

 

The Fix

You cannot repair a broken filter assembly with glue or tape due to the system's high water pressure. You will need to replace the entire filter/drain assembly. [1, 2, 3]

1. Depressurize the system: Turn off your RV water pump or city water supply, and open a hot water faucet to relieve the pressure.
2. Remove the old filter: Lift the thumb latch on the easy drain lever to drop the assembly down.
3. Inspect the housing: Look inside the chamber for any leftover pieces of broken black plastic.
4. Install the replacement: Pop the new filter cartridge into place and snap the lever back up to lock it. [1, 3]

 

How to Prevent It

Truma designed the filter to fail (break) first to prevent the internal mixing vessel from freezing and causing a $2,000+ tank replacement. During winterization, always make sure you pull the yellow lever, remove the filter cartridge, and drain the water entirely. Do not reinstall the filter until you are ready to use the RV in the spring.

Edited 1 hour ago by Patriot

[DanielBoondock]

Cool this all makes sense. If I understand it now, the regular  brass valve is for hot over pressure, and the plastic sacrificial filter/rupture disk is to protect against freezing over pressure. Smart design 

Edited 29 minutes ago by DanielBoondock