PVI Industries QUICKDRAW PV500-26 - Manual (Page 14)

QUICKDRAW

Boiler Water Heater
14
PV500-26 06/12
8 TROUBLESHOOTING NOTES
Problem:
1. Outlet water temperature not constant
a. Cause: Insufficient recovery.
Solution: Check and be sure heater design rating is not being exceeded.
b. Cause: Malfunctioning or misadjusted thermostat(s).
Solution: If the thermostat or controller is always open, then the outlet temperature will vary with load.
Measure the tank temperature near the thermostat and compare to setpoint. The thermostat should turn on
and off within 5°F of setpoint. Replace if necessary.
Problem:
2. Heater recovery is slow or outlet temperature is below setpoint:
a. Cause: The temperature control valve is not opening properly.
Solution: Check for proper operation of valve actuator and linkage. Replace if necessary.
b. Cause: Return water not draining; water drain line is restricted; water check valve is leaking or have failed.
Solution: Reconfigure water return piping and check valve to allow for proper drainage. Check for
restriction in the water drain line.
c. Cause: Heat exchanger is breached.
Solution: Shut off the boiler water supply. Residual flow should stop after a short period of time. If the flow
continues, water is leaking from the tank into the coil. Disassemble, inspect, repair or replace as required
following the instructions in this manual.
d. Cause: Heat exchanger is fouled.
Solution: Inspect the heat exchanger for excessive scaling or fouling on the water side.
e. Cause: Abnormal operating conditions.
Solution: The water temperature has a significant effect on the efficiency of the heat exchanger. Check if
the setpoint is higher than specified. Confirm the measured flow rate with meters or by volume and rate.
Check that there are no other loads on the heater.
Problem:
3. No hot water at even low flow:
a. Cause: Control valve not opening.
Solution: Check that electrical coils are energized. If not, trace wiring problem. If so, the valve may be
faulty, the boiler water flow and temperature is inadequate, or the linkage (if applicable) is out of
adjustment.
b. Cause: The high-temperature limit is open.
Solution: Check the individual components of the system and repair or replace the failed component(s) as
necessary.
Problem:
4. Outlet temperature is too high:
a. Cause: Malfunctioning or misadjusted thermostat(s).
Solution: Check thermostat setting. Measure the tank temperature near the thermostat and compare to
setpoint. The thermostat should turn on and off within 5°F of setpoint. Replace if necessary.
b. Cause: The control valve is not closing properly.
Solution: See the adjustment instructions in this manual or for the specific temperature control valve
assembly installed. Replace worn components as required.