EZ Plate™ Storage Water Heater
20
PV500-64 12/14
9. 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 approximately 5°F of setpoint, unless user or service technician has adjusted to a larger or
smaller differential. Check wiring and replace if necessary.
Problem 2: Heater recovery is slow or outlet temperature is below setpoint:
a.
Cause
: The domestic water circulator pump is not operating properly.
Solution
: Check for proper operation of circulator pump. Replace if necessary.
b.
Cause
: Y-Strainer in domestic water line near the recirculation pump or in the boiler water supply line to the
heat exchanger is partially clogged.
Solution
: Blow down or clean boiler water and potable water Y-Strainers.
c.
Cause
: Boiler water control valve is not fully opening.
Solution
: Check for proper operation of boiler water control valve and service if necessary.
d.
Cause
: Heat exchanger is fouled.
Solution
: Inspect the heat exchanger for excessive scaling or fouling on the water side and clean if
needed.
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. Check if the boiler water to the heat exchanger is hot
enough and that the required flow is maintained.
Problem 3: No hot water even at low flow:
a.
Cause
: Boiler water control valve not opening.
Solution
: Check that electrical coils are energized. If not, trace wiring problem. If so, the valve may be
faulty, or the linkage (if applicable) is out of adjustment.
b.
Cause
: The domestic water circulator pump is not operating.
Solution
: Check that electrical power is being provided to the circulator pump during a call for heat. If so,
replace the pump. If not, trace wiring problem.
c.
Cause
: Malfunctioning or misadjusted thermostat(s).
Solution
: Adjust thermostat to energize domestic circulator pump (and boiler water control valve, if
supplied) at the desired water temperature. If the thermostat is properly adjusted and is not energizing the
domestic circulator pump, verify wiring and replace the thermostatic control if necessary.
d.
Cause
: The adjustable or fixed high-temperature limit is open.
Solution
: Check the individual components of the system and repair or replace the failed component(s) as
necessary.
