User Guide

V4943/V8943B,C,N; V4944/V8944B,C,L,N REGULATING DIAPHRAGM GAS VALVES
65-0214—5 10
pressure of the high fire pressure regulator. The high fire
setpoint cannot be achieved without the first stage solenoid
being energized.
Valve closing operation is identical to that described for V4943/
V8943B,C,N valves.
CHECKOUT AND TROUBLESHOOTING
WARNING
Explosion or Fire Hazard.
Can cause serious injury or death.
Do not let fuel accumulate in the combustion chamber.
If fuel is allowed to enter the chamber for longer than a
few seconds without igniting, an explosive mixture
could result.
CAUTION
Equipment Damage Hazard.
Failure to complete tests can cause equipment
damage.
1. Do not put the system into service until you have
satisfactorily completed all applicable tests
described in the Checkout section of the instructions
for the flame safeguard control, and any other tests
required by the burner manufacturer.
2. Close all manual fuel shutoff valves as soon as
trouble occurs.
Checkout
1. Valve outlet pressure measurements are made at a point
approximately five pipe diameters downstream from the
valve outlet. Consider pressure measurements made at
the outlet pressure tap as reference measurements only,
because turbulence and dynamic gas flow effects may
result in erratic pressure readings.
2. Shut off gas supply to valve and make sure valve is
closed when setting up pressure measuring equipment.
3. Set up pressure measuring equipment.
4. Make sure the valve is closed. Turn on the supply gas to
the valve.
5. Set the thermostat or controller to energize the valve and
check the final outlet pressure. See step 1. Allow enough
time for the system pressure to stabilize.
6. For regulator setpoint and spring range, please refer to
Table 3.
7. The low pressure regulator (V4944/V8944B,C,L,N) and
high pressure regulator V4943V8943B,C,N and
V4944/V8944B,C,L,N) adjustment screws are located
under the slotted aluminum screw cap(s) of the
adjustment screw housings (see Fig. 1). To adjust the
pressure setting:
a. Temporarily remove the slotted aluminum screw cap
and gasket from the housing that contains the
regulator adjustment setscrew.
b. Turn the adjustment setscrew clockwise to increase
the pressure setting or counterclockwise to decrease
the pressure setting. Allow adequate time (30 to 60
seconds) for the pressure to reach equilibrium
between pressure adjustments. A mechanical range
stop in the low pressure regulator adjustment of the
V4944/V8944B,C,L,N models controls the minimum
setting to which the low pressure regulator can be
adjusted. Do not turn the adjusting setscrew
counterclockwise beyond the point at which it is
stopped by the mechanical range limit.
c. After the regulators have been properly adjusted,
replace the gasket and slotted aluminum screw cap
on the adjustment screw housing.
8. Start the system and observe its operation through at
least one complete cycle to make sure the valve
functions properly.
Valve Leak Test (See Fig. 15).
This test checks the tightness closure of a gas safety shutoff
valve. It should be performed by a qualified technician during
the initial startup of a burner system, or whenever the valve is
replaced (see Service Information section). It is recommended
that this test also be included in scheduled inspection and
maintenance procedures.
1. De-energize the control system to make sure there is no
power to the safety shutoff valve (C) shown in Fig. 15.
2. Close the upstream manual gas cock (A).
3. Make sure the manual test petcock (F) is closed in the
leak test tap assembly (D).
4. Remove the leak test tap plug (valve outlet pressure tap
can be used as a test tap) and connect the test
apparatus to the leak test tap (D).
5. Close the downstream manual gas cock (E).
6. Open the upstream manual gas cock (A).
7. Run the safety shutoff valve (C) to its fully open position
(through the safety system); then immediately
de-energize the system to close the valve.
8. Immerse a 1/4 in. tube vertically 1/2 in. (13 mm) into a jar
of water.
9. Slowly open the test petcock (F).
10. When the rate of bubbles coming through the water
stabilizes, count the number of bubbles appearing during
a ten-second period. Each bubble appearing during a
ten-second period represents a flow rate of
approximately 0.001 cfh.
To meet code requirements, leakage must not exceed the
values in Table 5.
Table 5. Allowable Leakage Rates.
a
Based on air standard conditions, test pressures in
accordance with ANSI Z21.21, Section 2.4.2 and a maximum
of 235 cc/h per inch of seal-off-diameter. Seal-off diameter is
not the same as pipe size.
11. Close the upstream manual gas cock (A).
12. Close the test petcock (F), remove the test apparatus,
and replace the leak test tap plug (D).
13. Open the upstream manual gas cock (A) and energize
the safety shutoff valve (C).
14. Test with soap bubbles to make sure there is no leak at
the test tap (D).
15. De-energize the safety shutoff valve (C).
16. Open the downstream manual gas cock (E).
17. Restore the system to normal operation.
Pipe Size
(in.)
Allowable
a
Leakage
Number of Bubbles
per 10 sec.
1, 1-1/4 353 13
1-1/2, 2 453 16