11
MAINTENANCE
The Indirect Water Heater is intende d to provide a service life of many years. Components that require
service, however, may be subject to failure. Failure to use the correct procedures or parts in these
circumstances may make the water heater unsafe. The owner should arrange to have the following
inspections and simple maintenance procedure performed by qualified service personn el at the
frequencies suggested.
1. Boiler and Domestic Water Piping (Annual) – Ch eck all piping for signs of leakage at joint s, union s,
and shut-off valves. Repair as needed.
2. Temperature-Pressure Relief Valve (Annual) - The temperature-pressure relief valve should be
checked to ensure that it is in operating condition. To check the relief valve, lift the lever at the end of the
valve several times. The valve should seat properly and operate freely. If water does not flow, remove
and inspect for obstruction s or corrosion. Replace with a new valve of the recommended size as
necessary. Do not attempt to repair the valve, as this could result in improper o peration and a tank
explosion. In areas with poor wate r conditions, it may be necessary to inspect the temperature-pressure
relief valve more often than once a year. If the temperature–pressure relief valve on the heater
discharges periodically or continuously, it may be due to thermal expansion of water in a closed water
supply system, or it may be due to a faulty relief valve. Thermal expansion is the normal response of
water when it is heated. In a closed syst em, thermal expansion will cause the system pressure to build
until the relief valve actuation pressure is equaled. Then the relief valve will open, allowing some wate r to
escape, slightly lowering the pressure. Contact your water supplier or local plumbing inspector on how to
control this situation.
ABOVE ALL, DO NOT PLUG THE TEMPERATURE AND P RESSURE RELIEF VALVE. THIS IS NOT A
SOLUTION AND CAN CREATE A HAZARDOUS SITUATION.
3. Sediment (Annual, but harsh water quality may dictate more frequent service) - Depend ing on
water conditions, a varying amount of sediment may collect in the tank. Levels requiri ng service are
indicated by a small temperature difference in the supply and return lines (See also “Scal e” below).
Repeated flushing usually clears such material. As a preventive measure, water should be drawn from
the tank at the drain valve until it runs clear.
4. Scale (Annual) - Hard water may cause scale to build-up on th e outside of the heat exchanger coil. A
water softener will prevent this problem (See also “Sediment” above). Symptoms would include reduced
recovery capacity or reduced temperature differential between boiler supply and return lines. Repeated
flushing should resolve the problem.