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EFX 20/S19-2150
Troubleshooting: Thermostatic Mixing Valve
Before attempting to troubleshoot the valve or disassemble
the components, check for the following:
•
Stop/check valves are fully open (the slotted
stem must be flush with the stop/check cap) and
that all inlet and outlet shut-off valves are open
• Hot and cold inlet pipes are connected properly,
and that there are no cross-connectio ns or
leaking stop/check valves
• Water heater output is at least 15°F above the
set temperature.
Be sure to close the appropriate shut-off valves
prior to disassembly of the valve and reopen the
valves after inspection and repair is complete.
Problem
External leaks in the system
Either the NPT joints or the O-rings have been damaged.
No hot water flow (cold water
The thermostat has failed and, subsequently, the safety
flow only)
shut-off has engaged.
Limited water flow
The inlet shut-off valve may be partially closed or there
has been a significant decrease in water pressure.
Dirt and debris have collected on the check screen or
seat, limiting the movement of the stop and checks.
Temperature fluctuation or
The stop and check sections of the valve do not move
improper Temperature
freely.
Thermostat is slowly failing.
Inlet supply line to the mixing valve is being shared by
other pieces of equipment that are used only periodically,
such as laundry appliances or washdown stations. It may
reduce the inlet pressure to the mixing valve to less than
10 PSI. The supply line size may not be large enough to
supply both the valve and the other appliances.
Recirculation is not balanced.
Piston does not move freely and must be cleaned.
8
Cause
8/7/2020
Solution
Replace the NPT joints and/or O-rings where necessary. For replacement of
O-rings, contact your Bradley representative and ask for O-Ring Seal Kit (S65-
410).
Inspect Thermostat:
1. Remove the top cap and pull out the push rod and thermostat.
2. Insert a 7/16" dia. rod into the thermostat bellows.
3. Mark the length of the thermostat bellows (at room temperature, with 10 lb of
force, the bellows length should be approx. 1-3/16"—1-1/2" ).
4. If the thermostat bellows length is not in the proper range, the thermostat
must be replaced (it cannot be repaired). Contact your Bradley representative
and ask for Thermostat Kit (S65-408).
Clean Stop and check Valves:
Remove the stop and checks, clean the screen and seat and reassemble
the valve. Do not remove the seat. The components may be scraped with a
screwdriver to remove debris. A pair of tweezers works well for pulling debris out
from the seat. If the stop and checks need to be replaced, contact your Bradley
representative and ask for Check/Stop Kit (S65-491).
Clean Stop and Check Valves as described above.
Check Thermostat as described above, or replace.
Enlarge the supply line size, reconfigure the supply line or regulate the supply
usage.
Review recirculation set up on page 5.
See next page for piston disassembly and cleaning directions.
Bradley • 215-1809 Rev. E: ECO 20-09-011
Installation
Stop and Check
Stop/Check
Strainer
Valve Seat
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