DEMA 651AG SINGLE-FEED
INSTALLATION INSTRUCTIONS
I-715
Pg. 3 of 5
Rev. F- 42173 10/04/16
IV. SERVICING:
CAUTION: TURN OFF WATER SUPPLY BEFORE SERVICING.
A.
Proportioner fails to draw chemical:
1. Proportioner outlet tubing cut too short for priming. Pinch outlet tube to create backpressure, which will cause unit to
prime. The foot valve will keep the inlet tube primed thereafter.
2.
Insufficient water supply pressure. 20 psi is the minimum allowable pressure.
B.
Proportioner stops drawing chemical:
1. Inspect foot valve for dried chemical or dirt. Soak in hot water to clean.
2. Proportioner inlet clogged with dried chemical. Remove metering top and try injecting in hot water. If there is no
suction, remove proportioner and soak in hot water to clear interior passages.
C.
Air gap proportioner fails to draw chemical:
1.
Is correct tubing attached? The 1 GPM proportioner must have the skinny 7” long (3/16” I.D.) tubing.
2.
Is the nozzle on the top of the air gap in correctly? The bottom of the nozzle is flat. This is the part you can see as you
look up through the air gap window.
3.
Is the stream of water tight (0
) as it crosses the air gap? If not, you may have hard water scale build-up on the bottom
of the nozzle. SOAK THE NOZZLE IN PHOSPHORIC ACID, LIME SCALE REMOVER OR REPLACE NOZZLE.
4.
Does the priming pin on the outlet of the 4 GPM air gap have excessive hard waterscale and chemical residue build-up
on it? CLEAN WITH THE BLADE OF A KNIFE OR SOAK IN LIME SCALE REMOVER.
D.
Air gap proportioner is leaking out of vents:
Is the correct tubing attached? The 1 GPM and 4 GPM outlet tubing has a 9/16” ID. It is imperative that this diameter be
used, not the ½” ID tubing.
RETURNS:
NO MERCHANDISE MAY BE RETURNED FOR CREDIT WITHOUT DEMA’S WRITTEN
PERMISSION. RETURN MERCHANDISE AUTHORIZATION NUMBER REQUIRED IN
ADVANCE OF RETURN.
WARRANTY:
DEMA products are warranted against defective material and workmanship under normal use and
service for one year from the date of manufacture. This limited warranty does not apply to any
products which have a normal life shorter than one year or failure and damage caused by chemicals,
corrosion, improper voltage supply, physical abuse, or misapplication. Rubber and synthetic rubber
parts such as “o”- rings, diaphragms, squeeze tubing and gaskets are considered expendable and are
not covered under warranty. This warranty is extended only to the original buyer of DEMA
products. If products are altered or repaired without prior approval of DEMA, this warranty will be
void.
Defective units or parts should be returned to the factory with transportation prepaid. If
inspection shows them to be defective, they will be repaired or replaced without charge,
F.O.B. factory. DEMA assumes no liability for damages. Return merchandise authorization
number, to return units for repair or replacement, must be granted in advance of return.
