Slow spray in black tank

[goodcardio4u]

I have good water pressure, however, after 1hr my black tank shows 40% full - I can barely see any spray(looking down the toilet) and I can barely hear it running. After I dumped the black it still showed 30% full. Do I need to go old school with a wand sprayer?

[daleyocum]

Originally Posted by goodcardio4u

I have good water pressure, however, after 1hr my black tank shows 40% full - I can barely see any spray(looking down the toilet) and I can barely hear it running. After I dumped the black it still showed 30% full. Do I need to go old school with a wand sprayer?

I’m not sure about your trailer but modern ones have a one-way back flow preventer placed after the water intake and before the jets inside the black tank. I suspect that may be defective in your case, assuming the jets in the tank didn’t get clogged.

…or use a wand.

[richard5933]

Are we talking about a black tank spray on a 1972 trailer? If so, is it original? These things can get clogged so perhaps it's time for a replacement spray nozzle.

[Wazbro]

Originally Posted by richard5933

Are we talking about a black tank spray on a 1972 trailer? If so, is it original? These things can get clogged so perhaps it's time for a replacement spray nozzle.

I doubt a 1972 would have an original blank tank sprayer, my 1988 didn't come with one.

[goodcardio4u]

Thanks everyone for input - it’s a 2014 - i closed the dump valve and let the flush run for 1hr - according to the gusher it filled up to 40% - I dumped again - it says zero - I agree (without knowing) the sprayer must be partly clogged . I bet replacing nozzle would be xtra difficult - more investigation . I guess my first question is - what is the expected flow rate on the nozzle ? 1gal/min? - I measure something like 1 gal/ 3.5 min

[GammaDog]

Originally Posted by goodcardio4u

Thanks everyone for input - it’s a 2014 - i closed the dump valve and let the flush run for 1hr - according to the gusher it filled up to 40% - I dumped again - it says zero - I agree (without knowing) the sprayer must be partly clogged . I bet replacing nozzle would be xtra difficult - more investigation . I guess my first question is - what is the expected flow rate on the nozzle ? 1gal/min? - I measure something like 1 gal/ 3.5 min

I had this issue. As noted in a post above, a backflow preventer is mandatory. Mine is immediately inside of the exterior black tank flush connection fitting under a removable panel in the hallway closet. It is a simple replacement.

[daleyocum]

Originally Posted by goodcardio4u

Thanks everyone for input - it’s a 2014 - i closed the dump valve and let the flush run for 1hr - according to the gusher it filled up to 40% - I dumped again - it says zero - I agree (without knowing) the sprayer must be partly clogged . I bet replacing nozzle would be xtra difficult - more investigation . I guess my first question is - what is the expected flow rate on the nozzle ? 1gal/min? - I measure something like 1 gal/ 3.5 min

Something isn’t right at that flow rate. It may be clogged or it might be the backflow preventer (far easier to fix.). Mine fills to 50% (with a 60psi regulator I use outside after hearing of folks who blew up the sprayer accidentally) in around 5 minutes.

You could try renting a bore scope to peer down inside the toilet and see if you can see if the jets are clogged. If so perhaps VERY carefully filling the tank with water above the jet level and add some black tank additive and letting it sit overnight. Then try blowing it out the next day with water.

If you don’t see obvious clogs, it’s likely the backflow preventer.

[richard5933]

My trailer is from 1994 - the spray doesn't work at all. I've tried changing the back flow preventer with no change. From the looks of the nozzle it's just years of crud, corrosion, etc. which is causing the blockage. Changing it doesn't excite me, so we just deal with it.

Reality is that if you use proper protocol for dumping your black tank (dump it when it's full, never leave the valve open unless you're dumping, using enough water to flush, etc.) the tank will pretty much not need to be flushed. If the tank sensors are giving us a problem, I'll fill the tank about 1/3 of the way before pulling out of a campsite, add some tank treatment, and then let it all slosh around on the way to the next campsite. Then I drain it again and all is good.

Occasionally I'll use a stick wand flushing thingy through the toilet if necessary, but that's only about once a year. I just don't see the point of having the tank spic and span clean, only to have it mucked up again after the first flush.

[goodcardio4u]

Well it won’t be long and I’ll dump the holding and use the wand with star sprayer. After a good spray, I’ll hook up the hose to the flush line and see if it sprays, who knows. Thanks to all for your input.