THERMOSTATIC MIXING VALVE
INSTALLATION & SERVICING INSTRUCTIONS
ONE APPIAN WAY WORCESTER, MA 01610
P.O. BOX 59 WORCESTER, MA 01613
P: (800) 225-9529 • F: (800) 336-5133
www.webstonevalves.com
The Webstone TMV is designed for use in heating as well as domestic water systems and provides outlet temperatures ranging between
95°–131° F. The valve may be positioned in any orientation; designated lengths of straight piping before and after the unit are not required.
The Webstone Thermostatic Mixing Valve is a SAFETY VALVE. Inspect the TMV at least once per year to verify it is operating correctly. It may
be necessary to check the valve more frequently in installations with poor or unknown water quality. Use of a lter or strainer is required for
installations with poor or unknown water quality.
IMPORTANT: Follow all federal/national, state and local codes when installing, testing or performing work on systems. All parts are covered
by a lifetime warranty against manufacturing defects provided they are installed by a licensed plumber and operated under normal working
conditions. Disassembling will void this warranty. If you have any questions or comments, please contact us at (800) 225-9529 or visit us
on the web - www.webstonevalves.com.
WARNING: This valve was not designed for installations exposed to subfreezing conditions; use suitable insulation if this possibility exists in your
installation. Subjecting the Webstone TMV to heat during installation may damage the valve internals. The Webstone TMV is designed for use in
water systems only. DO NOT use the TMV in steam systems. The use of excessive thread sealant may cause the Webstone TMV to fail.
INSTALLATION
1. Prepare the system for the TMV installation:
a. Flush the system thoroughly before fitting the Webstone TMV. It is critical
to ush all debris from the pipework before installing the Webstone TMV.
This step eliminates the most common cause of system difculties.
b. Check the specications of your Webstone TMV against site
parameters, such as temperature and pressure. Rectify any
conditions outside the valves specications before installation.
2. For products without integral check valves
a. Attach a union assembly to each end of the valve body.
For sweat connections with integral check valves (Series 7520 ONLY)
a. Ensure that the check valve is removed from all union connections.
b. Connect a union tting to the hot, cold and mix water lines.
c. SWT all connections, applying heat to the piping, not directly to the tting.
d. Insert a check valve (poppet end rst) and clip into the union ttings
on the hot and cold water supply lines. (see image to right)
e. Attach a union assembly to each end of the valve body.
For threaded connections with integral check valves (Series 7420 ONLY)
a. Attach a union assembly with check to each of the hot and cold valve inlets.
b. Attach the union assembly without the check to the mixed water outlet.
3. Ensure that each union nut is aligned accurately to the
valve and that washers are properly in place.
4. Connect the hot water supply line to the inlet marked HOT.
5. Connect the cold water supply line to the inlet marked COLD.
6. Connect mixed water line to outlet marked MIX, also indicated with a ow arrow.
7. Fully tighten the union assemblies at each connection.
8. Set the output to the desired temperature* by aligning the numbers on the
handle with the mark on the valve body in accordance with the table below:
Handle Marking 1234
Output
Temperature
95°F
(35°C)
109°F
(43°C)
119°F
(48°C)
131°F
(55°C)
* Output temperature may vary slightly due to seasonal changes in cold
water supply temperatures. Numbers on handle are calibrated at the time of
manufacture and should be used for initial commissioning of valve only.
9. Verify that the correct mixed water temperature is being achieved:
a. Open the nearest water outlet supplied by the TMV to a ow of 2 to 3 gpm.
It is important to test the temperature at the nearest outlet to ensure
water delivered to any outlet is not greater than the desired maximum.
b. Allow the water to reach a stable temperature and measure.
10.Turn the handle clockwise to decrease, or counter-clockwise
to increase the outlet temperature as needed.
CHECK
VALVE
O-RING
POPPET END
GROOVE FOR
RETAINING CLIP
WASHER
UNION
FITTING
UNION
NUT
HOT OR COLD
SUPPLY PIPE
RETAINING
CLIP
TMV
BODY
SYSTEM FLOW
SWT CHECK VALVE INSTALLATION
(SERIES 7520 ONLY)
If desired, the temperature setting can be xed on
the Webstone TMV by locking the handle in place:
1. Set and verify the mixed water temperature
2. Remove screw and handle
3. Align internal pin on handle with slot on
temperature limit stop
4. Replace handle and secure screw
NOTE: Field calibration may be needed if
handle has been removed or locked.
* Temperature limit stop slot and alignment mark
on valve body must remain aligned at all times.
Removing or tampering with the white alignment
clip will void the manufacturer’s warranty
SETTING TEMPERATURE LOCK
(OPTIONAL)
HANDLE
INTERNAL PIN
TEMPERATURE
ALIGNMENT MARK
ON VALVE BODY*
TEMPERATURE
LIMIT STOP
TEMPERATURE
LIMIT STOP SLOT*
2
3
4
1
2
3
4
1
