lp-790 Revision Date 1.3.22
16
If draining of the water heater is necessary, open the T&P valve or
a hot water tap to prevent vacuum buildup in the tank and piping.
The risk of scald injury increases as you increase water temperature.
Use extreme caution whenever adjusting the water heater
thermostat or mixing valve. Failure to follow the instructions in this
warning statement could result in serious personal injury or death
from scalds.
Be sure to disconnect electrical power before performing service.
Failure to do so could result in electrical shock, property damage,
serious personal injury, or death.
Table 6 - Troubleshooting - *See Scald / Electric Shock Warnings and Caution Statements, this Table.
Part 8 - Troubleshooting
Problem
Reason
Remedy
No Hot Water
Manual disconnect switch turned off
Turn switch on
1. Blown fuse or circuit breaker tripped
2. Shorted or improper wiring
3. Circuit overloaded
4. Grounded element or thermostat
1. Replace fuse or reset breaker
2. *Replace, repair, or rewire per detail
3. *Provide adequate circuit to reduce load
4. *Replace
Manual Reset High Limit (ECO) open
1. Thermostat(s) defective or out of calibration
2. ECO(s) defective or out of calibration
3. Heat build-up due to loose wires
Refer to Part 6, this manual.
1. *Replace thermostat(s)
2. *Lower thermostat setting or replace
3. *Tighten wire connections
Improper wiring
*Check and rewire per Wiring Detail
Improper piping
*Check and correct piping
Not Enough Hot
Water
Thermostat or Mixing Valve setting too high or low
Change setting as required
Heater undersized
Reduce rate of heater use
Defective element(s)
*Check amperage, replace element if low
Miswired or defective thermostat causing only one
element to work
*Check wiring or replace thermostat
Water Too Hot or
Not Hot Enough
Thermostat or Mixing Valve setting too high or low
Change setting as required
Thermostat out of calibration
*Replace thermostat
Thermostat access panel(s) and/or insulation not in place
Inspect and replace as needed
Thermostat(s) not resting tightly against mounting plate
Ensure that retaining spring(s) or mounting screws hold
thermostat(s) tightly to mounting plates
Mixed Water
Temperature Does
Not Change When
Adjusted or Cannot
be Obtained
Hot and cold supply lines are reversed
*Check and correct piping
Strainers are blocked
Clean strainers
Inlet temperatures are not within specific limits
Ensure inlet temperatures are within the specified limits for
the valve
Reduced or
Fluctuating Flow,
or No Flow
Hot and cold supply lines are reversed
*Check and correct piping
Strainers are blocked
Clean strainers
Fluctuating supply pressure
Install pressure regulating valves
T&P Valve
Discharges
Improperly seated valve
Open and close the handle to try to reseat valve
Thermal expansion in closed water system
Install a thermal expansion tank
Damaged / defective valve
Replace relief valve
NOTE:
DO NOT plug T&P valve under any circumstances
Water Leaks
Loose connection between inlet / outlet piping, mixing
valve, relief valve, and/or hex nut union on tank fittings
Tighten fittings
Damaged seal ring washer / gaskets
Replace seal ring washer / gaskets as required
Damaged gasket around heating element(s)
Inspect and replace gasket if necessary
Hot Water Odor
High sulfate or mineral content in water supply
Drain and flush water heater. Refill.
Bacteria in water supply
Check with local water treatment specialist or utility to
identify and address this problem.
Noisy Operation
Hard water scale built up on element(s)
*Remove and clean
Excessive water velocity
Reduce water velocity by installing a pressure reducing valve
