
INSTALLATION INSTRUCTIONS
No. 127W Pressure Regulator For Water
(Single Seat, Diaphragm, Spring Type)
No. 127W may be installed with diaphragm above or below the line.
1. Before installing, be sure pipe ends are reamed and threads
are cut to size. Blow out lines to remove all loose scale and
other foreign matter that can damage valve seat.
2. Install regulator in the line with the arrow on the body pointing in the direction of flow.
3. Connect 1⁄4" or 3⁄8" equalizer pipe as shown from the
diaphragm chamber to a point in the reduced pressure
4. Install a needle valve in the control line. If uneven pressure
should cause the regulator to pulsate, its action can be stabilized by throttling the valve.
NOTE: 15" diameter chambers are standardly furnished with a pressure relief valve, factory set at 60 psi to protect the chamber from
excessive pressure. A drain line should be attached to the relief
valve to channel any potential discharge to a safe place of disposal.
line not less than 18" but preferably a greater distance from
the regulator.
IMPORTANT
When a reducing valve is used, it makes a closed system; therefore, a pressure relief valve must be installed in the downstream side of the regulator to protect equipment against excess pressure which is built up by the expansion of water from
the domestic hot water supply tank or heater.
INSTALLATION
No. 127W Recommended Installation
Installed in tandem with smaller size regulator to
improve system performance and extend valve life.
Bypass Line (Optional)
High
Pressure
Binding Nut
Packing Nut
Below
Horizontal
Line
Bonnet
Adjusting
Collar
No. 127W
Line
1
⁄4" or 3⁄8"
Equalizer Pipe*
▼
High Pressure
*One inch size No. 223
regulator to handle low
demands. Set 10 psi
higher than 127W.
Reduced
Pressure
Needle Valve
*NOTE: Always connect equalizer pipe into a straight
run of the line, as shown.
TO ADJUST : When diaphragm is above the line, turn adjusting
collar from left to right to increase the reduced pressure opposite to decrease reduced pressure.
When diaphragm is below the line, turn adjusting collar from
right to left to increase the reduced pressure - opposite to
decrease the reduced pressure.
A steel rod is provided to turn adjusting collar.
LIMITED WARRANTY: Watts Regulator Company warrants each product against defects in material and
workmanship for a period of one year from the date of original shipment. In the event of such defects within the
warranty period, the Company will, at its option, replace or recondition the product without charge. This shall
constitute the exclusive remedy for breach of warranty, and the Company shall not be responsible for any
incidental or consequential damages, including without limitation, damages or other costs resulting from labor
charges, delays, vandalism, negligence, fouling caused by foreign material, damage from adverse water
conditions, chemicals, or any other circumstances over which the Company has no control. This warranty shall
be invalidated by any abuse, misuse, misapplication or improper installation of the product. THE COMPANY
MAKES NO OTHER WARRANTIES EXPRESS OR IMPLIED EXCEPT AS PROVIDED IN THIS LIMITED WARRANTY.
IS-127W 0223 EDP# 1910315 © Watts Regulator Co., 1996 Printed in U.S.A.
*This optional installation provides greatest maintenance
serviceability and better regulation for installations where
extreme low demand periods are frequent. Smaller regulator
serves low volume demands, extending life of larger valve.
Tighten packing nut lightly if leaks occur around stem. Repack
stem when light nut pressure cannot stop leak. Do not tighten
packing nut enough to bind stem. This causes uneven regulation
and excessive stem wear.
TO CLEAN: Inspect or replace worn valve disc, disconnect control
pipe and unscrew bonnet from valve body using blunt tool and
hammer on bonnet lugs. Lift entire topwork clear of body.

INSTALLATION INSTRUCTIONS
No. 4" 127W Pressure Regulator For Water
(Single Seat, Diaphragm, Spring Type)
No. 127W may be installed with diaphragm above or below the line.
IS-127W
1. Before installing, be sure pipe ends are reamed and threads
are cut to size. Blow out lines to remove all loose scale and
other foreign matter that can damage valve seat.
2. Install regulator in the line with the arrow on the body pointing in the direction of flow.
1
3. Connect
phragm chamber to a point in the reduced pressure line
or to the special tapping provided in the low pressure side
of the regulator body. This tapping gives you a convenient,
economical means of attaching the equalizer line, facilitating installation and eliminating fittings.
⁄4" or 3⁄8" equalizer pipe as shown from the dia-
4. Install a needle valve in the control line. If uneven pressure should cause the regulator to pulsate, its action can
be stabilized by throttling the valve.
NOTE: 15" diameter chambers are standardly furnished with
a pressure relief valve, factory set at 60 psi to protect the
chamber from excessive pressure. A drain line should be
attached to the relief valve to channel any potential discharge
to a safe place of disposal.
IMPORTANT
When a reducing valve is used, it makes a closed system; therefore, a pressure relief valve must be installed in the downstream side of the regulator to protect equipment against excess pressure which is built up by the expansion of water from
the domestic hot water supply tank or heater.
ADJUSTMENT
TO ADJUST : When diaphragm is above the line, turn adjust-
No. 4" 127W Recommended Installation
Installed in tandem with smaller size regulator to
improve system performance and extend valve life.
Needle Valve
4" 127W
High Pressure
*3⁄4" size No. 223
regulator to handle low
demands. Set 10 psi
higher than 127W.
Reduced
Pressure
ing collar from left to right to increase the reduced pressure
- opposite to decrease reduced pressure.
When diaphragm is below the horizontal line, turn adjusting
collar from right to left to increase the reduced pressure opposite to decrease the reduced pressure.
A steel rod is provided to turn adjusting collar.
Tighten packing nut lightly if leaks occur around stem. Re-
pack stem when light nut pressure cannot stop leak. Do not
tighten packing nut enough to bind stem. This causes uneven regulation and excessive stem wear.
TO CLEAN: Inspect or replace worn valve disc, disconnect
control pipe and unscrew bonnet from valve body using blunt
tool and hammer on bonnet lugs. Lift entire topwork clear
of body.
*This auxiliary installation provides greatest maintenance
serviceability and better regulation for installations where
extreme low demand periods are frequent. The smaller size
regulator effectively serves low volume demands.