Grey Water Tank Problem

[charliem]

[font size="3"]OK Folks. After thinking this through a bit more, I'm going to suggest simple tests to determine if your gray water system is working properly. We'll be testing only for proper drainage, not for available capacity or gauge accuracy.

[/font][ol type="decimal"][li][font size="3"]Start with city water hooked up and the gray tank empty. No Crystal water required.[/font][/li][li][font size="3"]Run the cold wide open in both sinks simultaneously. If both sinks drain
 properly until water backs up into the shower your gray system is good
to go. The shower is the lowest drain in the system and should be the
first to back up when full.[/font][/li][li][font size="3"]If either sink backs up, gurgles or burps you may have a faulty Air Admittance Valve (AAV). [/font][/li][li][font size="3"]Empty the gray tank (yes, you can dump this on your lawn unless you have an HOA).[/font][/li][li][font size="3"]Remove one AAV and retest. Whichever AAV , when removed, allows the test to complete successfully is probably bad.[/font][/li][li][font size="3"]Empty the gray tank (under cover of darkness if you have an HOA).[/font][/li][li][font size="3"]Run both hot and cold water in shower wide open. (WH off)[/font][/li][li][font size="3"]If neither sink burps and water begins to back up into the shower your gray is good to go.[/font][/li][li][font size="3"]If either sink burps before water backs up in the shower your gray vent
pipe may be blocked or pushed too deeply into the gray tank. Check for
vent blockage on the roof. If the vent is not physically blocked it
probably is installed improperly. If the main vent becomes inoperative,
and the two AAVs are good,  the air trapped in the tank will be forced
out through the sink P-traps. [/font][/li][/ol][p][font size="3"]
[/font][/p][font size="3"]This test more closely simulates normal usage. Specifically, dumping 5 gallons of water all at once into the shower could overpower the wet vent, producing a false indication of failure.
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[jtelles3993]

Charlie, I think you've hit the nail on the head!

[charliem]

[quote timestamp="1426634732" author="@surfsup" source="/post/8023/thread"]Charlie, I think you've hit the nail on the head![/quote][font size="3"]Thanks. I just hope I don't hit the nail on my finger[/font] [attachment id="648" thumbnail="1"]

[leslie]

Until you are off the pain meds, leave the nails alone! On the other hand, with the pain meds, you might not feel any pain...

[shovelhead]

Stay on the meds....

[video src="https://youtu.be/BeskbiJjCXI"][/video]

[hdrehder]

I did the grey water tank measuring test today.  Put 36 gallons down the shower before it backed up. Then tried an additional gallon in the kitchen sink. It was slow to empty. So looks like I don't have a problem, at least at the moment. Will continue to watch closely, as I still believe that it was backing up too quickly at one point. Thanks Charliem for all of the analysis and others for posting your results.  

Also pulled the anode for the first time (have had the trailer since June 2014). It was pretty corroded with lots of chunks eaten out of it.  Ordered two new replacements from Amazon and will benefit from the recent posts here as I thread the new one in.  

Very thankful for this forum!

[shovelhead]

[quote timestamp="1427064453" author="@spunk4" source="/post/8316/thread"]I did the grey water tank measuring test today.  Put 36 gallons down the shower before it backed up. Then tried an additional gallon in the kitchen sink. It was slow to empty. So looks like I don't have a problem, at least at the moment. Will continue to watch closely, as I still believe that it was backing up too quickly at one point. Thanks Charliem for all of the analysis and others for posting your results.  

Also pulled the anode for the first time (have had the trailer since June 2014). It was pretty corroded with lots of chunks eaten out of it.  Ordered two new replacements from Amazon and will benefit from the recent posts here as I thread the new one in.  

Very thankful for this forum![/quote]Dont try  Charlie's recommendation.  Too hard to get that trailer on end.

[jeeps]

[font size="3"](Hello, this is Brenda's husband, Bryce.)

We just ran the test and also calibrated our newly installed see level monitor.
We are having the same venting problem with our grey tank.  After about 10 gallons the sinks started gurgling and spitting.
It seems to me that the AAV valve can only be defective if it does not either let air into the system and/or lets air out.  It is designed to be a one way valve only to keep a vacuum from forming when draining the tank or sinks.  If CW fixed the problem by replacing the AAV valve it means they must have disabled it by allowing it to let air out of the system and into the trailer. So the problem would appear to be fixed but it is not.


IMO, the problem has to be the vent.  And if the vent was blocked on the roof, it would start gurgling immediately and wouldn't wait till the ten gallon point.

I will be calling CL.  


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[jtelles3993]

Hey Bryce, we agree with your assessment, faulty AAV just doesn't make sense. However, be ready for them to want to try changing your AAVs first thing - keep us posted!

Also like to know how you're like'n the See Level system?

[charliem]

[font size="3"]
Bryce,

I agree 100% with your thoughts, but there is one thing. When your sinks were gurgling were you filling from a sink or from the shower? Were you dumping 5 gallons at a time into the shower?

The roof vent for the gray tank is also the drain path for the shower. The shower P-trap connects to the vent pipe just above the tank; then the vent continues down into the tank. I think that if the shower is filled such that water is standing (after dumping 5 gallons) the water flowing down through the vent could actually block the vent thereby making it inoperative as a vent. Water would still drain from the shower, but the air in the tank would be forced up and out through the sinks. You would not normally see this because the shower head only allows 2 gal/min. If this is true the system could be working correctly with good AAVs and normal flow rates into sinks and shower. The 5 gallon dump would be an abnormal mode. I think a more realistic test would be to fill from the kitchen sink only and see if you can get to a full tank without gurgling from the bath sink.

I've been examining every angle I could think of to vindicate CW's fix, but I just can't square it. It's been suggested I test the AAV by hooking a garden leaf blower to the drain pipe and see if air is blowing back into the camper via the AAV. I'm a bit out of commission for a while (total knee replacement), but I plan to try it as soon as I can. It just doesn't make any sense. When I first started talking with Don at LL he agrees maybe the vent pipe had been pushed down too far. The conversation sort of died out when CW claimed to have fixed the problem. CW even claimed they reran my 5 gallon dump test into the shower with no sink gurgling. I was on my way out on a trip so didn't argue and it did work OK while on the trip.  I'm glad you came up with the same conclusion and I'll be interested in how you do with LL.
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[solds88]

I haven't performed the gray water test yet, but plan on doing so in the near future. Also, this is something that you may want to try: Crawl underneath and measure the height of the holding tank, then insert a tape measure into the vertical vent pipe and locate the lower edge of the pipe, note the measurement, then lower the tape to the bottom of the tank and note this measurement. This will give you an idea of how deep the vent pipe has been inserted into the holding tank.  

[charliem]

[quote timestamp="1427259652" author="@james" source="/post/8413/thread"]Also, this is something that you may want to try: Crawl underneath and measure the height of the holding tank, then insert a tape measure into the vertical vent pipe and locate the lower edge of the pipe, note the measurement, then lower the tape to the bottom of the tank and note this measurement. This will give you an idea of how deep the vent pipe has been inserted into the holding tank.  [/quote][font size="3"]Good idea![/font]

[jeeps]

[font size="3"](This is Brenda.)

Bryce talked to Don at LL who was very nice, but as you predicted, immediately wanted to address the AAVs, but when Bryce questioned him on it, he didn't disagree nor try to pursue that idea.  The implied feeling was that they know the AAVs aren't the issue.  He did say that the vent can sometimes get pushed down and that we can try getting up on the roof and pulling it back up, which has us wondering how it's attached to the gray tank.  Also, the vent is straight (w/o bends) so we will definitely try measuring it as James suggested and then see if it can be pulled up.  Hopefully, if that works, we don't pull it too far and out of the tank ..... hence measuring it first.  Will report back.    (I say "we" but it'll be Bryce doing it all ..... bless him.)

As we are second owners, we have no warranty, but IF it was installed incorrectly in the factory, it sure seems like they should fix it.  But I guess that's the price we pay for the money we saved buying it used.  [/font]

[charliem]

[quote source="/post/8433/thread" timestamp="1427300098" author="@brenda"][font size="3"](This is Brenda.)

Bryce talked to Don at LL who was very nice, ........... 

He did say that the vent can sometimes get pushed down and that we can try getting up on the roof and pulling it back up, which has us wondering how it's attached to the gray tank.   Hopefully, if that works, we don't pull it too far and out of the tank ..... hence measuring it first. 
[/font][/quote][font size="3"]Note to Bryce: My early conversations with Don were similar. He said the vent stack was assembled on the chassis before the roof was put on. He thought maybe the roof installation could be pushing the vent pipe down into the tank. Before you pull up on the vent consider how the shower P-trap must be attached. The P-trap attaches to to the vent stack just above the floor. I think this must be a rigid T fitting with no vertical slip built it. I don't know how the vent attaches to the tank below. Does it have some kind of gasket slip joint? If not, how can it be pushed into the tank and what happens to the shower P-trap when this pushing occurs. We still don't know all we need to know.

Let me know what you think of my idea of overloading the vent with 5 gallon dumps into the shower. If you shine a flashlight down from the top of the vent while the shower is draining you can see water running into the vent stack. I think it could be clogging the vent and preventing air from entering the tank. The test would be filling the tank from the sinks.
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[solds88]

[p]I agree 100% with Charlie, if you try adjusting the vent pipe you will probably compromise the roof seal and the tank seal, and you may break the p-trap. Have you ever heard the old saying "Jump out of the frying pan into the fire", this would certainly be the case. I have a possible fix in mind, but it may not be feasible. If you could remove the abs pipe on the side of the holding tank you may be able to see, and perhaps even be able to correct the supposed problem. See attached, drill a series of vent holes as as shown in the drawing. It would require a jobbers drill bit(s) and maybe an extension. A long shot???[/p][p]
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