Why Does The Rv Gray Tank Read Empty When Full? (Quick Fix)
One morning, I smelled something awful from the sinks. So, I checked my RV gray tank panel to see if it was full, but the sensor indicated it was empty. Then, I tried to sink some water, and it didn’t drain, and immediately I checked my RV gray tank, which was full.
I have found that the main reason for an RV gray tank to be empty when full is a dirty sensor inside the gray tank, which determines the drainage level. Unfortunately, a dirty sensor cannot read accurately, which is why it shows false readings.
A full gray tank of used water cannot be a pleasant experience. That is why now I will tell you why this happened, along with some quick fixes to get you out of that smelly situation.
Why Does The Rv Gray Tank Read Empty When Full?
There can be several reasons for the false reading of an RV gray tank that says it’s empty when full. I have already mentioned one significant reason, but let’s look at other possible causes for this issue and quick fixes.
1. Dirt On The Gray Tank Sensor
This is the most common cause because the sink flushes a lot of dirt and food grease onto the gray tank, which causes dirt to attach to the sensor. The sensor is a gravity fill sensor, so when it gets dirt around, it cannot detect the water level properly and sends false signals.
Quick Fix 01:
- Get the back of your RV and locate the gray tank. It is the Gray colored tank among the three.
- Open the cap and manually flush all the water out. Use safety equipments.
- Use pressure water inside the tank, so all the dirt washes away.
- Close the tank and check the sensor panel reading. It should be okay now.
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2. Jammed Vent
As sinks drain a lot of heavy stuff like food and hair from the shower, there is an ample possibility of those getting in the way of the water drain vent lines. It is like our home drainage system, which is very common.
Jammed vent lines will not allow water to pass through to the gray tank, and the sensor will not be able to detect it properly and end up showing the wrong water level in the gray tank.
Quick Fix 02:
- Check the RV gray tank the old-fashioned way to see if it’s full.
- Pour water on each sink and see which one is not passing water.
- After finding out the blocked vent, follow the pipes using your RV model manual.
- Detect the open vent and clean it. If it’s not removable, apply pressure using a clogged drain blister.
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3. Broken Sensor/ Wiring Issue
In rare cases, the sensor can be at fault. The wiring from the sensor to the sensor panel might be worn, torn, or detached. Thus, the sensor panel shows a false reading
Quick Fix 03:
- Three wirings connected from the gray tank to the sensor panel. Check if they are installed correctly.
- If the sensor is broken, you must install a new one. It is effortless and can be done without mechanics.
- Replace any Torn wires.
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Different Types Of Holding Tanks
Every RV has three tanks, all of which have other purposes. But one common thing is that they all have a sensor that detects the water level and functions almost the same way. So I will tell you about those, so you can know if they malfunction.
Note: All three tanks are settled side by side, and the color is identical to the name.
| Tanks | Use |
| Fresh Water Holding Tank | Storage for fresh water on the road, like drinking water, baths, and washing anything. |
| Black Water Holding Tank | Only for the toilet/ sewage channel. |
| Gray Water Holding Tank | Drain water through sinks of the bathroom, kitchen, shower, washer, etc. |
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FAQs.
No one likes a bad smelly situation anywhere, especially when they travel for vacation in their RV. And to stay away from this unpleasant situation, RV owners and users asked several questions about the gray tank issue, some of which are below.
How To Prevent RV Gray Tank Sensor Issues?
Daily maintenance is one of the most practical methods in order to avoid RV gray tank sensor issues. One primary reason for the false reading on the gray sensor is dirt which we mentioned above. So, clean that gray tank once in a while.
How Do I Know If My RV Gray Tank Is Full or Empty?
When technology fails, you need to follow the classic method. Two ways can ensure if the RV gray tank is full or empty. First, pour water on any sink kitchen or bathroom and let it drain. Another is to open the gray tank cap and see the water level.
How Would I Know If It Is A False Reading On RV Gray Tank Sensor?
RV gray tanks usually have four different levels of reading on the sensor panel outside the wall behind the passenger seat. This is because the sensor works with a gravity fill. So, if you are getting imbalanced readings, check if that fill is dirty with tissue or food grease.
Why Does My RV Gray Tank Sensor Read Full When Empty?
This can happen because of a faulty, broken RV gray tank sensor, not a dirty sensor. In chronic cases, most false readings come from dirt and grease all over the sensor. But, a faulty sensor can show a reading like a gray tank full even when it’s empty.
Conclusion
Almost every gray tank sensor is dirty because a lot of dirt and debris passes through the tank. But, only sometimes will you face this problem. It only happens when the sensor gets too dirty and hasn’t been checked for months. Gray tank, black tank, all of them require some maintenance after a certain period.
You may not like cleaning it yourself, so cleaning services are available almost everywhere. If you are comfortable, then it is a straightforward process to fix it.
Keep it clean, and you will see results. Also, these quick fixes come at no cost unless your sensor or the reader breaks, which will cost you some. Besides, you can get rid of that smelly situation instantly anywhere on the road by parking and space 10 minutes of your time.
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Zayan is an accomplished author and a go-to expert for all things RV and camper-related. With a passion for adventure and a knack for problem-solving, he has spent years exploring the open road and fine-tuning his knowledge of recreational vehicles.
Zayan’s writing is a testament to his expertise, offering readers practical solutions to common RV dilemmas. Whether it’s troubleshooting mechanical issues, optimizing space, or planning the perfect road trip, Zayan’s insightful advice and engaging storytelling make him an invaluable resource for both seasoned travelers and newcomers to the world of RVing.
