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Dosatron’s D8R – 40 GPM Troubleshooting Video


Hello. I’m Jason and welcome to Dosatron university. Today, Dosatron’s Troubleshooting video series features the Dosatron D8R 40 GPM Injector. In this video, I will use a strap wrench and a seal pick. It’s best to perform troubleshooting in a clean area or if your injector is in line, cover your stock tank, so you won’t lose any parts. The three key areas to trouble shooting are 1. The injector is not drawing the concentrate
but is clicking 2. The injector is pushing water down into
your stock solution tank but is clicking 3. The injector isn’t clicking. The first two are the most common. If the injector is clicking but not drawing
the concentrate, it could be as simple as the strainer is plugged with debris.
Take a look at the strainer. If it is clogged, clean it and retest your
Dosatron. If there is still no suction, but the Dosatron
is clicking, turn the water on. Unscrew and remove the suction hose nut and
suction hose and check to see if you feel suction on your finger.
If so just cut a half inch on your suction hose and reattach.
You should see the liquid begin moving up the suction hose.
If you don’t see liquid moving up the hose or you don’t feel suction on your finger,
turn the water off. Move the air bleed lever on the bell housing
back and forth a few times to release the pressure.
Using the bell wrench, loosen the bell housing and unscrew to remove.
Set it aside. Grasp the white plastic bridge, and pull the
piston straight out of the body. Take a close look at the plunger seal for
nicks, scratches, or wear. If you see damage or don’t remember the
last time you changed the seal, just replace the plunger assembly now.
To change the plunger assembly, hold the piston firmly and unscrew the plunger assembly.
Thread the new plunger assembly onto the piston and hand tighten. Carefully insert the piston back into the body and press it down until it stops.
Reinstall the bell housing hand tight. Your injector should now be drawing the concentrate. If your injector is pushing water down into the concentrate tank, it’s time to investigate the check valve. To do this, remove the hose nut and hose,
set aside. Unscrew the injection stem nut about four
turns and pull the injection stem assembly straight down.
Now, unscrew and remove the check valve nut and pull the check valve assembly down out
of the stem. If the upper portion sticks in the stem, push
it out with something like a pen. Then press down on the top of the cone shaft
to release all the check valve parts. Inspect all the check valve parts.
If they are dirty, you may be able to soak, brush it off, and reinstall.
If you see damage or don’t remember the last time you changed these parts, just replace
them now. To reassemble the check valve, align the spring on the shaft of the cone and slide it into the valve guide. Next, hold the cone down and press the retainer into the guide.
Then set the seal with the raised center portion up onto of the barb, press it into the guide.
Now, press the check valve assembly into the stem as far as it will go.
You may have to give it a little twist. Thread the check valve nut onto the white
stem assembly hand tight. Press the injection stem assembly into the
body, making sure the injection scale is aligned with the flow arrow on the body.
Twist the assembly until it aligns with the threaded black sleeve.
Then make sure the black tags align with the grooves in the threaded black sleeve and tighten
the injection stem nut hand tight. When properly installed, you should be able
to see one thread showing between the stem and the body.
Thread the suction hose nut onto the hose. Slide it onto the barb and hand tighten the
nut. This should stop water from dripping back
into the concentrate tank. If the injector isn’t clicking or is stalling
at low flow, we need to investigate the piston. Using the strap wrench, loosen the bell housing
and unscrew to remove. Set it aside.
Grasp the white plastic bridge and pull the piston straight out of the body.
Holding the piston, press the push rod up and pull it down.
It should click in both directions. If not, please give us a call for assistance.
You can visually inspect the upper and lower flanges on the piston shell.
If they are worn or have deep scratches the piston shell needs to be replaced.
Another way to check the flanges, is by doing a fit test.
To test the upper flange, invert the piston and insert it squarely half way into the bell
housing. It should be a snug fit.
To test the lower flange, remove the plunger by turning it a quarter turn counterclockwise
and pulling it straight out. Insert the piston into the body squarely about half way.
It should stay in place. If either is lose, the piston shell needs
to be replaced. For assistance in replacing the piston shell,
contact Dosatron technical service at 800-523-8499. Now, insert the piston back into the blue
body and hand tighten the bell housing. That’s all for now.
We hope this video has been helpful in troubleshooting your Dosatron D8R Injector.
For more information, give us a call at 800-523-8499 or visit us online at dosatronusa.com
To see our other videos check out our youtube channel or the video link on our website.
I’m Jason and this is Dosatron University. Thanks for watching.

Bernard Jenkins

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