25
CAUTION
BEFORE MANUALLY OPERATING THE V AL VE, MAKE SURE THAT
A DRAIN LINE HAS BEEN ATT ACHED TO THE V AL VE TO DIRECT
THE DISCHARGE TO AN OPEN DRAIN. FAILURE TO T AKE THIS
PRECAUTION COULD MEAN CONTACT WITH EXTREMELY HOT
WATER PASSING OUT THE VALVE DURING THIS CHECKING
OPERATION.
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.
Two common corrections are listed in the Checklist and Service
Information which appears later in this manual.
ABOVE ALL, DO NOT PLUG THE TEMPERATURE AND PRESSURE
RELIEF VALVE. THIS IS NOT A SOLUTION AND CAN CREATE A
HAZARDOUS SITUATION.
INTERNAL CIRCULATING PUMP
The BTH-300 & 400 are factory equipped with an internal
circulating pump. This pump is maintenance free with no oil
needed for periodic lubricating.
VENT SYSTEM
Examine the vent system every 3 months. Points of inspection
are as follows:
1. Check for obstructions and/or deterioration of vent piping and
vent hood. Replace immediately where needed.
2. Vent pipe and vent hood screen should be cleaned of foreign
material and soot. The screen is located inside the vent hood
outlet and is accessible from the outside of the hood. Do not
reach inside the vent hood when the heater is in operation.
3. Check all vent system connections for leakage and reseal as
required using Hi Temp Silicone sealer or equivalent.
CIRCULATING PUMP - FIGURE 26