PVI Industries PV500-25 - Manual (Page 14)

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Steam Heater
14
PV500-25 06/12
c. Cause: Piping flow restricted.
Solution: Calculate the flow velocity and expected friction loss. If excessive, larger inlet and outlet piping
are necessary.
d. Cause: Main valve malfunction.
Solution: Refer to the valve manual for instructions on main valve repair.
e. Cause: Main valve undersized.
Solution: Check steam pressure before and after steam valve. Check valve capacity against the load. If
insufficient, increase trim or valve size.
Problem:
4. Outlet water temperature not constant.
a. Cause: Insufficient recovery.
Solution: If the thermostat or controller is always open, then the outlet temperature will vary with load. See
above for causes of insufficient recovery.
b. Cause: Malfunctioning thermostat.
Solution: Measure the tank temperature near the thermostat and compare to setpoint. The thermostat
should turn on and off within 5°F of setpoint.
Problem:
5. Unusual noises coming from heater.
a. Cause: Flashing condensate.
Solution: Pinging, rattling or banging noises are usually the result of condensate flashing to steam.
Condensate not draining properly. Check that there is not excessive condensate lift. Check the sizing of the
trap. Check that the condensate receiver is not pressurized. Check that there is no blockage in the
condensate line from the trap to the receiver. Unclog any strainers in the system.
Problem:
6. Heat exchanger visibly leaking.
a. Cause: Plumbing connection loose.
Solution: Check and tighten plumbing connection.
b. Cause: Double-wall heat exchanger tube leak.
Solution: If one of the tube walls is breached, a double-wall heat exchanger will leak at the joint between
the tubesheets. Isolate the heater and replace the heat exchanger.
Since PVI cannot control the use of the water heater, water conditions, or maintenance, the warranty on
the heat exchanger does not cover poor performance, structural failure, or leaking due to an excessive
accumulation of scale