|
04-13-2021, 05:43 AM
|
#1
|
Junior Member
Join Date: Sep 2020
Location: Colorado Springs
Posts: 9
|
Black Tank Flush blockage
Hi there Gang from Colorado. Does anyone out there have any knowledge of how to clear a blockage at the black tank flush? The symptom is that fresh water is spaying out of a pressure relief valve which is located in the bathroom base cabinet. The flush line comes from the water service port into the cabinet on its way to the flush tank. Under the sink the line is intersected by this plastic valve then goes on to the tank. The water is not making it to the tank (no, it is not frozen). The black tank release valve is open and the tank is empty. The camper is a 2018 Outback 298RE if that helps. The last time it was used was last fall. When I tried to flush it for the first time this spring is when it backed up water into the camper. All other plumbing is working fine and was winterized (of course there is no way to winterize this line-it doesnt appear to be a rupture anyway). Tech support is scratching their heads and want to send out a mobile tech to drop the belly line etc.
18 years of owning campers and this is a first.
|
|
|
04-13-2021, 05:52 AM
|
#2
|
Site Team
Join Date: Oct 2011
Location: Joppa, MD
Posts: 11,758
|
That is not a pressure relief valve it is a vacume break or antisiphone valve. I don't know what "tech support" you're talking about but that's a very common device that fails with regularity. You can remove and replace it for a few dollars. The toughest part is getting to it as it's often up high behind the bathroom sink.
__________________
Marshall
2012 Laredo 303 TG
2010 F250 LT Super Cab, long bed, 4X4, 6.4 Turbo Diesel
|
|
|
04-13-2021, 05:58 AM
|
#3
|
Site Team
Join Date: Jul 2014
Location: Modesto
Posts: 20,351
|
I would remove the anti siphon valve, and use low pressure air (10-20 PSI) and see if you can clear it. I have had to drop the underbelly and pull the rinser out of the tank before. The nozzle holes are very small and I had to use a pick.
__________________
2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.
|
|
|
04-13-2021, 06:07 AM
|
#4
|
Senior Member
Join Date: Aug 2012
Location: Waco, Tx
Posts: 5,457
|
Quote:
Originally Posted by colouiss651
Hi there Gang from Colorado. Does anyone out there have any knowledge of how to clear a blockage at the black tank flush? The symptom is that fresh water is spaying out of a pressure relief valve which is located in the bathroom base cabinet. The flush line comes from the water service port into the cabinet on its way to the flush tank. Under the sink the line is intersected by this plastic valve then goes on to the tank. The water is not making it to the tank (no, it is not frozen). The black tank release valve is open and the tank is empty. The camper is a 2018 Outback 298RE if that helps. The last time it was used was last fall. When I tried to flush it for the first time this spring is when it backed up water into the camper. All other plumbing is working fine and was winterized (of course there is no way to winterize this line-it doesnt appear to be a rupture anyway). Tech support is scratching their heads and want to send out a mobile tech to drop the belly line etc.
18 years of owning campers and this is a first.
|
Quote:
Originally Posted by flybouy
That is not a pressure relief valve it is a vacume break or antisiphone valve. I don't know what "tech support" you're talking about but that's a very common device that fails with regularity. You can remove and replace it for a few dollars. The toughest part is getting to it as it's often up high behind the bathroom sink.
|
Almost the first thing I do to a new trailer when I pick it up is replace the anti-siphon valve with 2 90` fittings and a bit of PEX.. then I use a hose bib anti-siphon fitting and pressure regulator at the hydrant.
Funny thing is... I've never had a leak
OH YEAH... the spray bar is probably not blocked... just the valve leaking..
__________________
2015 Ford F350 DRW 6.7 Diesel XL
2020 Avalanche 313 RS
|
|
|
04-13-2021, 06:54 AM
|
#5
|
Junior Member
Join Date: Sep 2020
Location: Colorado Springs
Posts: 9
|
Quote:
Originally Posted by flybouy
That is not a pressure relief valve it is a vacume break or antisiphone valve. I don't know what "tech support" you're talking about but that's a very common device that fails with regularity. You can remove and replace it for a few dollars. The toughest part is getting to it as it's often up high behind the bathroom sink.
|
Thanks much. I will try replacing that. In troubleshooting this, I tried forcing 150psi air into the tank after disconnecting the valve. It made no sense to me that air would not go into the tank. Does that make a difference?
|
|
|
04-13-2021, 07:12 AM
|
#6
|
Senior Member
Join Date: Sep 2020
Location: Jacksonville
Posts: 993
|
Be very careful when using air pressure. The pipe n fittings are not made for high pressure. Normally about 30-40 psi is all u want to try
__________________
Bob/Kay
Jacksonville, Nc
2020 Keystone Cougar 5th wheel 29 rks traded now
2021 3761 fl Montana 5th wheel
Pulled with a 2022 F350 King Ranch
Retired LEO after 35 years just enjoying life now.
|
|
|
04-13-2021, 07:13 AM
|
#7
|
Senior Member
Join Date: Aug 2012
Location: Waco, Tx
Posts: 5,457
|
Quote:
Originally Posted by colouiss651
Thanks much. I will try replacing that. In troubleshooting this, I tried forcing 150psi air into the tank after disconnecting the valve. It made no sense to me that air would not go into the tank. Does that make a difference?
|
The holes are very small and any real volume of air would backflow especially at 150 psi.. The spray bar is only designed for 40-50 PSI.. If you didn't blow it apart... I'd just make up two 90 degree PEX fittings with 2" of 1/2" PEX between them to replace the fitting and then hook a regulated water hose to it and see if water runs through it..
__________________
2015 Ford F350 DRW 6.7 Diesel XL
2020 Avalanche 313 RS
|
|
|
04-13-2021, 09:13 AM
|
#8
|
Senior Member
Join Date: Sep 2019
Location: Florissant
Posts: 703
|
Quote:
Originally Posted by Javi
(snip) then I use a hose bib anti-siphon fitting and pressure regulator at the hydrant.
|
Educate me. What is a “hydrant?”
__________________
Skids
2019 Bullet 248RKS
|
|
|
04-13-2021, 09:28 AM
|
#9
|
Site Team
Join Date: Mar 2011
Location: Gaylord
Posts: 26,997
|
Quote:
Originally Posted by skids
Educate me. What is a “hydrant?”
|
https://www.zoro.com/woodford-mfg-fr...-3/i/G1141743/
The "typical" fresh water connection used in all COE and many State and public campgrounds in areas where the temperature falls low enough to cause freeze damage to a conventional "spigot".
__________________
John
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
|
|
|
04-13-2021, 10:01 AM
|
#10
|
Senior Member
Join Date: Sep 2019
Location: Florissant
Posts: 703
|
Thanks John. I wondered what those were called.
__________________
Skids
2019 Bullet 248RKS
|
|
|
04-13-2021, 10:25 AM
|
#11
|
Senior Member
Join Date: Nov 2017
Location: Picacho, Az
Posts: 6,809
|
If don't have one of these get one ASAP & use it at whatever hydrant or spigot you connect your rv water hose to, it will keep your water pressure regulated.
If you have one of these, save as a spare or toss it, it restricts the flow regardless of pressure.
Also if you don't have an EMS/surge protector (EMS is required) connected to the incoming powers source, get one of them also ASAP & use every time you connect your shore power. The EMS will protect your sensitive electronic equipment from most every type of electrical fault.
__________________
Full-timed 10+ years
Sold '13 Redwood FB
Traded '13 GMC Denali DRW D/A
Replacement undetermined
|
|
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Threads |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|