Dema 491M Installation Manual

DEMA® MANIFOLD VALVE MODELS: 491M AND 492M

DEMA® SOLENOID VALVE MODELS: 491S AND 492S

INSTALLATION INSTRUCTIONS

1. INSTALLATION:

Models 491M and 491S have 1/8” NPT and Models 492Mand 492S have 1/4” NPT female pipe connections. The
valves may be installed in any position other than with the coil down. Make sure fluid flows in the direction of the
markings on the body indicating IN and OUTLET. Apply pipe dope to male threads, hand tighten, and then turn 1 ½
times with a wrench. Note: Wiring must comply with Local and National Electrical Codes.

2. FLUIDS:

Valves are intended for water, air, light oil, and other noncorrosive fluids. They should not

be used
for gasoline and other hazardous or explosive fluids. Maximum fluid temperature is 200° F (93.3°C).
Ambient temperature shall not exceed 120°F (48.8°C).

WARNING: NOT FOR USE WITH HAZARDOUS OR CORROSIVE OR EXPLOSIVE FLUIDS.

3. OPERATION:

When the solenoid coil is energized, the plunger is pulled up, thus opening the “port”. This releases the pressure
above the seat. When the coil is de-energized, the solenoid plunger is pushed down by the kick-off spring and closes
the port.

4. SPECIFICATIONS:

Maximum operating pressure differential: 125 PSI
Safe working pressure: 300 PSI
Flow factor (CV): Dependent on orifice – Refer to catalog.
Maximum temperature: 180 degree fluid temp.

120 degree ambient temp.
Power: 10 Watts
Volt-Amp rating:

120/60 24/60

93°C

200°F

INRUSH

HOLDING

24 24
15 14

5. TROUBLE SHOOTING:

A) Failure to open:

1) No power or low voltage.

2) Coil burnout (over voltage) or an open circuit to coil connections.

3) Dirt, scale or sludge may prevent the plunger from operating.

4) Pressure differential exceeds the MOPD rating of the valve.

5) Metering stem may be in closed or restrictive position.

B) Failure to close:

1) Coil still energized.

2) Pressure in the outlet or valve installed backward.

3) Dirt, deposits, on valve seat or enclosing tube, keeping plunger from closing.

4) O-Ring beneath valve seat (26.17/23.11V/23.11) (models 491M & 492M) may be missing.

C) Water Hammer:

Quick acting valves may cause water hammer when operated. If this occurs, it may be minimized by the use of a
standpipe or other commercially available shock absorber installed near the valve inlet.

CAUTION: WHEN SERVICING THE VALVE, BE SURE THAT REPLACEMENT PARTS HAVE BEEN

INSTALLED ACCORDING TO THE DRAWING ON THE LAST PAGE.

I-744 Pg. 1 of 3
Rev. A-28235

DEMA® MANIFOLD VALVE MODELS: 491M AND 492M

DEMA® SOLENOID VALVE MODELS: 491S AND 492S

INSTALLATION INSTRUCTIONS

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.

I-744 Pg. 2 of 3
Rev. A-28235

DEMA® MANIFOLD VALVE MODELS: 491M AND 492M

DEMA® SOLENOID VALVE MODELS: 491S AND 492S

INSTALLATION INSTRUCTIONS

41.14.1

41-9-7-

41-9D-7-

*

49.5

49.7

49.3.B

49.3.V

49.3.EP

49.4

41.5.8

30.5V.14

30.5.14

49.2.3

49.2.4

49.2.5

49.2.6

49.2.8

49.2.10

26.17

23.11V

23.11

41.119.1

USED WITH 41.9.7­ONLY

* THESE PARTS ARE NOT APPLICABLE
TO MODELS 491S & 492S

*

49-6-B

PART N0.

30-5-14
30-5V-14
41-5-8
41-14-1

41-14-2

41-9-7­41-9D-7­41-119-1
49-2-3
49-2-4
49-2-5
49-2-6

DESCRIPTION

O-RING SEAL (EP)
O-RING SEAL (VITON)
O-RING SEAL (BUNA-N)
TOP PLUG SCREW
RETAINING SCREW (USED WITH MODELS
491M()M & 492M()M ONLY)
NAME (SPECIFY VOLTAGE)
NAME (SPECIFY VOLTAGE)
BRACKET (USED WITH 41-9-7- ONLY)
VALVE SEAT 3/64
VALVE SEAT 1/16
VALVE SEAT 5/64
VALVE SEAT 3/32

PART N0.

49-2-8
49-2-10
49-3-E
49-3-B
49-3-V
49-4
49-5
49-6-E

49-6-B

49-6-V

49-7

49-6-V

49-6-EP

VALVE SEAT 1/8
VALVE SEAT 5/32
PLUNGER ASSY EP
PLUNGER ASSY BUNA-N
PLUNGER ASSY VITO N
ENCLOSING TUBE ASS Y
TUBE NUT
METERING SCREW ASSY EP (USED WITH
MODELS 491M()M & 492M()M ONLY)
METERING SCREW ASSY BUNA-N (USED WITH
MODELS 491M()M & 492M()M ONLY)
METERING SCREW ASSY VITON (USED WITH
MODELS 491M()M & 492M()M ONLY)
KICK-OFF SPRING

41-14-2

DESCRIPTION

I-744 Pg. 3 of 3
Rev. A-28235