Hubbell ST - Troubleshooting; Heating Capacity Issues

c. Spence Valves: There is no main spring adjustment on Spence Valves. To
set temperature on the water heater:
(1) Turn pilot spring adjustment “A” clockwise until all tension is off the
spring.
(2) Refer to unit start-up section and start unit except for thermostat setting.
(3) Turn spring adjustment “A” counter-clockwise until the wheel is firmly
against the spring.
(4) Continue to turn wheel “A” one 360° turn or until steam begins to pass
thru the valve.
(5) Allow unit to heat until the valve closes off.
(6) If unit is not up to temperature at this point, continue to turn adjustment
wheel ½ turn, stop and allow valve to shut off.
(7) Repeat this cycle until unit is up to the desired temperature.
SECTION V – TROUBLESHOOTING
(See separate component O&M for additional details.)
Symptom Probable Cause Corrective Action / Remedy
Gradual loss of heating
capacity.
Tubes are fouled. Clean tubes per Section III,
annual scheduled maintenance.
Excess silt in bottom of
tank.
Drain and flush tank per Section
III , annual scheduled
maintenance.
Air or water leak in
temperature control.
Repair or replace per separate
O&M.
Ruptured diaphragm on
air or water operated
valve.
Repair or replace per separate
O&M.
Debris in Accritem. Clean Accritem.
Strainers clogged. Clean strainers per Section III,
annual scheduled maintenance.
Pump impellor
deteriorated.
Repair or replace per separate
O&M.
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