Read the instruction book! This sometimes painful advice
isn’t usually followed by us either, but unless you already know what you’re
doing around a chemical pump, the installation information given in the first pages is
valuable.
Ninety percent of the time, half your problem is in the
plumbing! If the pump isn’t working properly, turn the upper (or speed) knob from the
off (or external) position you normally have it in to work with the flowmeter to the 100 %
position. Listen for the clicking sound of the solenoid -- if you hear that OK, count the
blinks of the control panel light. If you get a count of 95-105 per minute, then better
that 9 times out of 10 your problem is in the pump’s liquid end. If you don’t
hear the click, or the blink rate is off, replace the pump with a back-up and send it back
for examination and/or repair.
The most common problem seen with a metering pump is a loss of
prime, which is also usually related to the plumbing. Check that the tubing is cut off
squarely, and is short enough that the foot valve hangs straight (with the screen up off
the bottom of the drum). Hold the tubing down firmly on the fittings while you tighten the
coupling nuts. If there is any problem holding the prime, put a two foot chunk of ½"
schedule 40 PVC pipe over the suction tubing (jam the foot valve coupling nut into the
bottom of the pipe) – this forces the curved tubing to hang straight and keeps the
ball on the seal ring, thus maintaining prime.
If you’ve isolated a problem to the pump’s liquid end,
and you’re sure it’s not a priming problem, look next for leaks from the slot
behind the head (ruptured diaphragm), and then for plugs, in the injection check valve or
the checks in the pump head.
Once you’ve checked all of the above, including the
installation itself (customers have been known to change things around just to help), and
have 10 or 15 minutes in to the pump – consider replacing it with a loaner and
sending it back for a check-up. Your time is too valuable to get hung up for too long
working on the equipment.
Even though the hints are aimed at preventative or
problem-solving maintenance, the good news is that most of your installations will come
off without a hitch. If you get the original start-up down smoothly, you’ll save
yourself a lot of call-backs. Finally, if a problem repeats itself, or if you can’t
find the right answer here, please don’t hesitate to call us – we’d be glad
to help.
