Installation / Operation Instruction Manual

Maintenance continued-

If the temperature and 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 system, 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 water

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

PRESSURE 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) – Depending on water conditions, a varying

amount of sediment may collect in the tank. Levels requiring

service are indicated by a small temperature difference in the

supply and return lines (See also “Scale” 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 the

outside of the heat exchanger coil. A water softener will prevent

this problem (See also “Sediment” above). Symptoms would be

reduced recovery capacity or reduced temperature differential

between boiler supply and return lines. Repeated flushing should

resolve the problem.