Installation Instructions
Performance
a)
A performance test should be conducted while operating all appliances at full load. This will test if
adequate pressure is reaching each appliance under full-load conditions. To accomplish this, measure
the line pressure at the appliance connection while operating the appliance.
b) The inlet pressure for a typical gas appliances under full load conditions should measure a minimum of 4
inches of water column pressure for natural gas and a minimum 10 inches water column pressure
for propane. If these pressure ranges cannot be obtained, a slight adjustment to the service regulator
or the pounds-to-inches regulator may be necessary to increase line pressure.
Adjustment
a) Adjustment can be accomplished by first removing the regulator seal cap to expose the adjusting
screw. Turning the screw clockwise will increase outlet pressure, turning it counter-clockwise will
decrease pressure.
b) If spring adjustment will not produce the desired outlet pressure, check to make sure the main supply
pressure is adequate
. If the main supply pressure is adequate, consult factory for other line-regulator
options. Do not continue to turn regulator adjusting screw clockwise if the outlet pressure readings do
not continue to increase.
This may result in over-firing due to loss of pressure control, should
there be a subsequent increase in inlet pressure.
c)
The 2 PSI system pounds-to-inches regulator can be adjusted with an outlet pressure ranging between 7 to
9 inches water column pressure for natural gas and 10 to 12 inches water column for propane. The regula-
tor must be adjusted according to the manufacturers recommended procedure. A pressure gauge mounted
just downstream of the regulator can monitor the set pressure under various loads.
d) The regulator outlet is pre-set and labeled at the factory for either 8” natural gas or 11” propane.
e) The average natural gas appliance is designed to operate at 3 to 4 inches water column pressure, and a
pressure difference of 1 to 2 inches of water column across the appliance regulator which will prevent slow
regulator response. Thus, the appliance regulator will operate best at 4 to 6 inches W.C. inlet pressure. The
pounds-to-inches system regulators for natural gas are set to deliver 8 inches of W.C. outlet pressure under
load to allow for 3 inches of W.C. pressure drop in the tubing.
f) The average propane gas appliance is designed to operate at 10 to 10-1/2 inches water column pressure.
Thus, the pounds-to-inches regulators for propane gas are set to deliver 11 inches water column outlet
pressure under load to allow for 0.5 inches water column pressure drop in the tubing.
36
Line Regulator Capacity Tables
Natural Gas
P
ropane
M
axitrol Pressure Drop Table
C
apacity @ Pressure Drop - 0.64 sp gr gas expressed in CFH (m
3
/
h)
Model Number 7.0" W.C. (17 mbar) 1/2 psi (34 mbar) 3/4 psi (52 mbar) 1 psi (69 mbar)
3
25-3 145 (4.0) 204 (5.8) 250 (7.0) 289 (8.2)
3
25-5A 338 (9.6) 476 (13.5) 583 (16.5) 673 (19.1)
Capacity value for most typical 2 PSI parallel systems when trunk run is sized for 1 PSI pressure drop and a 3/4
PSI drop across regulator
Maxitrol Pressure Drop Table
C
apacity @ Pressure Drop - 1.52 sp gr gas expressed in MBTUH LP
M
odel Number 7.0" W.C. (17 mbar) 1/2 psi (34 mbar) 3/4 psi (52 mbar) 1 psi (69 mbar)
325-3 234 (6.4) 328 (9.3) 403 (11.3) 465 (13.2)
3
25-5A 544 (15.5) 766 (21.7) 939 (26.6) 1084 (30.8)
Capacity value for most typical 2 PSI parallel systems when trunk run is sized for 1 PSI pressure drop and a 1/2
PSI drop across regulator