‘22 Tab 400 fresh water drain won’t drain

OysterTab400

Have 3/4 fresh water in tank and open fresh water drain but valve won’t drain. Trailer is level and I’ve tried clearing obstructions with a thin plastic cord but only goes in about 3” before it hits what I assume is a check valve.  Tried reverse flushing with the hose hoping that would clear a blockage but nothing. Any ideas? I don’t like driving around with a full fresh water tank. 

MuttonChops

The trailer Fresh Water Tank does not have check valves on the tank drain line.
Some basic questions (we all can have brain-dead days)
    ++  Are you sure the tank has water in it . . . tank monitor light could be wrong.
    ++  Are you opening the Fresh Water Tank Drain and not the trailer plumbing 'low point' drain?

If you know tank has water and the correct drain is open,
Suggest you try a more robust wire/tube/etc to confirm the drain line is not blocked.

pthomas745

 Where exactly is your fresh water tank drain?  Towards the rear of the trailer? The trailer may be better off being tilted slightly toward where ever the drain might be. On my 2017 320, the fresh tank drain is behind the door on the passenger side.  I usually drop the tongue to help the water flow there.

OysterTab400

Thanks for the responses. Yes, draining the fresh water tank drain (single valve to the left of cold and hot water drain) below the Nautilus on my ‘22 tab 400. Also, I know it’s 3/4 full because I filled the tank at home and used about 1/4 of the tank camping. 

The location is rear left. It’s level and has drained before in this position so not sure it’s a leveling issue, especially since it’s so full. 

Sharon_is_SAM

Check the fresh tank overfill/vent.  If it is clogged by a mud dauber/bug nest, you may not be able to drain.  

If it is clear, can you use a compressor hose to displace any debris that has accumulated?  

Lastly, is it possible the tank drain valve has malfunctioned and is stuck closed?

OysterTab400

Nucamp customer service emailed me back and suggested compressed air through the fresh water drain. Took a few tries but it dislodged some foreign objects (looked like some very small animal eggs full of very bad smelling white stuff which might be another problem) but the fresh water drain started draining again right away. They recommended not using compressed air through the overflow because that could improperly pressurize the system. Thanks for the help everyone. Wanted to be sure to post the solution here for others. 

Bill&Suze

@OysterTab400, what is the recommended air pressure nuCamp advised you to use?

pthomas745

Between this group and the FB pages, the "something living in the fresh tank vent" issue has happened way too many times. 

OysterTab400

They don’t specify an air pressure. I used my car compact air compressor with the attachment for inflating yoga balls and held it in the fresh tank drain hole. At first it made water come out the cold drain valve that I had open so I closed that. Took a few tries and held it there less than 30 seconds but it eventually dislodged the blockage.