Hubbell Electric Heater Company EMV - Manual (Page 10)

MONTHLY INSPECTION – MIXING VALVE
NOTE: The mixing valve should be tested in conjunction with regular OSHA required shower/eyewash
testing. These tests confirm that the equipment is safe and operational and also serve to purge potential
bacteria laden water from the system.
1. Monitor temperature
a. Record all information on the Mixing Valve Inspection and Test Log, see page 11.
b. Using an accurate thermometer, turn on the shower/eyewash and record the maximum start-up spike
temperature of the water.
c. After a few minutes of running, record the normal temperature.
d. If the temperature does not match required temperature (±3°F), recalibrate the mixing valve. See Section
V, Service and Replacement of Parts, Re-Calibrate Mixing Valve.
2. Monitor flow rate
a. OHSA/ANSI recommends a potable water system maintain a pressure of 30-psig minimum with a flow
rate of 20-GPM minimum to a shower head and 3-GPM minimum to an eye/face wash fixture.
b. One simple method of testing is to collect the water in a 5-gallon container. At the required flow rate, the
shower head will fill the container in approximately 15 seconds and the eye/face wash will fill the
container in approximately 15 seconds.
QUARTERLY INSPECTION
1. Monitor thermostat
a. Let water heater completely heat to a designated thermostat setting.
b. After thermostat satisfies (that is, when the thermostat actually clicks off), draw water from the relief
valve.
c. Compare water temperature of drawn water to the temperature setting of the thermostat when it
satisfies. Normal variation between the two points is approximately + 7°F.
d. If these two readings do not coincide within acceptable tolerances and verification has been made of
the accuracy of the temperature-reading gauge, replace the thermostat.
2. Lift test lever on relief valve and let water run through valve for a period of approximately 10 seconds.
This will help flush away any sediment that might build up in water passageways.
3. Inspect element flange for leakage as follows:
a. Shut off Power Supply.
b. Remove element housing cover.
c. Visually inspect heating element gasket for evidence of leaks.
d. Rub finger around gasket that is between the heating element and tank flange for any evidence of
moisture. If moisture is present or a water drip is observed, follow procedure outlined in Section V.
4. Check for loose electrical connections. Tighten as necessary.
ANNUAL INSPECTION
1. Flush tank as follows
a. Shut off power supply.
b. Close valve on hot water outlet piping.
c. Open valve on drain piping.
d. Cold water inlet line pressure will be strong enough to flush sediment from the bottom of the tank out
through the drain. Let water run for 3-4 minutes.
e. Close drain valve.
f. Open hot water valve.
g. Turn power supply ON.
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