Fault Diagnosis
Symptom Cause/Action
1. Only Hot or Cold Water From
Outlet
a. Inlet supplied reversed (i.e. hot supply to cold inlet) can be diagnosed by
isolating the inlet supplies and removing the valve cartridge. With cartridge
removed, turn the water on at each supply individually and at a very low ow rate
(water will run out of the front of the valve body). Identify which inlet is the hot
supply and which is the cold supply. Re-install the cartridge matching the raised
H and C on the cartridge body to the inlets as identied.
b. No hot water reaching mixing valve. Check
c. Check strainers and inlet ttings for blockage.
d. Refer to symptom 5 below.
e. Installation conditions continuously outside operating parameters
f. Normal function of mixing valve: indicates hot water inlet supply failure/
interruption.
2. Fluctuating or Reduced Flow
Rate
Normal function of mixing valve when operating conditions are unsatisfactory.
a. Check strainers and inlet/outlet ttings for ow restriction.
b. Ensure that minimum ow rate is sufcient for supply conditions.
c. Ensure that dynamic inlet pressures are nominally balanced
d. Ensure that inlet temperature differentials are sufcient.
e. (Subject to rectification of supply conditions). Check the thermostatic
performance; renew cartridge assembly if necessary.
f. Normal function of mixing valve: indicates hot water inlet supply failure/
interruption.
3. No Flow From Mixing Valve
Outlet
Check that inlet ow controls are fully open.
a. Check strainers and inlet/outlet ttings for blockage.
b. Cold supply failure; thermostat holding correct shutdown function: rectify, and
return to 2e above.
4. Blend Temperature Drift Indicates operating conditions changed.
a. Refer to symptom 2 above.
b. Hot supply temperature uctuation (rectify and refer to Commissioning).
c. Supply pressure uctuation (rectify and refer to Installation).
5. Hot Water in Cold Supply or
Vice-Versa
Indicates check valves require maintenance (refer to Maintenance).
6. Water Leaking form Valve Body Seal (s) worn or damaged.
a. Obtain seal pack, renew all seals.
b. (If leak persists from around temperature spindle). Renew cartridge assembly.
7. Cold Water does Not Flow After
Hot Supply Failure
a. Incorrect valve model installed. Check and rectify.
b. Incorrect internal cartridge installed. Check identication code and rectify
c. Check strainers and inlet/outlet ttings for blockage
d. Cold supply failure.
8. Hot Water continues to Flow
After Cold Supply Failure
a. Incorrect Valve commissioning. Validate the Commissioning.
b. Insufcient temperature differential see validate commissioning.