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HIGH TEMPERATURE LIMIT CONTROLS (ECO)
Both the ELECTRONIC CONTROL and SURFACE MOUNT
CONTROL model water heaters are equipped with one or
more ECO (energy cut out) non adjustable high temperature
limit control(s). An ECO is a normally closed switch that opens
(activates) on a rise in temperature. If the ECO switch contacts
open (activate) due to abnormally high water temperatures it
will lock-out and disable further heating element operation. It is
important that a qualified service agent be contacted to determine
the reason for the ECO activation before resetting the ECO. Once
the reason has been determined and corrected the ECO(s) can
be reset as follows:
SURFACE MOUNT CONTROL MODELS
Surface Mount Control models have multiple surface mounted
Thermostat/ECO combination controls. One for each installed
heating element - see the Surface Mount Control wiring diagrams
in this manual. The ECO high temperature limit switch contacts
on each control will open when the tank temperature reaches
approximately 200°F/93°C. When the ECO switch contacts open
(activate) voltage to ONE heating element ONLY is terminated to
prevent further heating operation of that element. Voltage may
still be present at other heating elements and they may still be
heating the water.
The ECO is a manual reset switch. Should one or more ECO
activate, the tank temperature must drop below 120°F/49°C
before an ECO can be reset. To manually reset an ECO:
1. Disconnect the power supply to the water heater.
2. Allow the tank temperature to cool below 120°F/49°C.
3. Remove the front control cover from the effected control(s).
4. Press the manual reset button on each of the effected controls.
Once the control(s) has been reset the control cover should be
replaced prior to restoring power to the water heater.
ELECTRONIC CONTROL MODELS
The ECO high temperature limit switch is located inside the
immersion Temperature Probe (two red wires) on ELECTRONIC
CONTROL models. The ECO switch contacts will open when the
water temperature reaches approximately 202°F/94°C. When
the ECO switch contacts open (activate) the electronic control
system locks out and displays a Fault message. Voltage to the
contactor coils and heating elements is terminated to prevent
further heating operation.
Should the ECO activate, the water temperature must drop below
140°F/60°C before the control system can be reset. Once the
water temperature has cooled below this point the power supply
to the water heater must be turned off and on again to reset the
control system.
THERMOSTAT CONTROLS
The water heaters covered in this instruction manual are equipped
with adjustable thermostat controls to control water temperature.
Hot water temperatures required for automatic dishwasher and
laundry use can cause scald burns resulting in serious personal
injury and/or death. The temperature at which injury occurs
varies with the person's age and duration of exposure. The
slower response time of children, the elderly or disabled persons
increases the hazards to them. Never allow small children to use
a hot water tap or draw their own bath water. Never leave a child
or disabled person unattended in a bathtub or shower.
The water heater should be located in an area where the general
public does not have access to set temperatures.
Setting the water heater temperatures at 120°F will reduce the
risk of scalds. Some States require settings at specific lower
temperatures.
TEMPERATURE REGULATION
THERMOSTAT SETTINGS - SURFACE MOUNT CONTROL
These models have multiple thermostat/ECO combination controls
one for each heating element installed. These thermostats are
set from the factory at 140°F/60°C. Set the thermostat dial at the
lowest setting which produces an acceptable hot water supply.
This will always give the most energy efficient operation.
The water heater is supplied with thermostats that may come from
different manufactures and have different temperature indications
as described below.
THERMODISC
Thermodisc thermostats are adjustable from approximately
120°F (49°C) (lowest setting) to 181°F (83°C) (highest setting)
see Figure 13. These thermostats are set from the factory at
approximately the 140°F (60°C) setting. The over temperature
device (ECO high limit) attached to each thermostat has a
manual reset.
APCOM THERMOSTATS
Apcom thermostats have three designated set points; LO, MED
and HI. See Figure 14.The approximate equivalent temperatures
for these three settings are: LO = 140°F (60°C), MED = 160°F
(71°C) and HI = 181°F (83°C). These thermostats are set from the
factory at the Low 140°F (60°C) setting. The over temperature
device (ECO high limit) attached to each thermostat has a manual
reset setting.
Figure 13. Thermodisc
Thermostat Controls
Table 5 shows the approximate time-to-burn relationship for
normal adult skin.
Table 5. Time to Burn Relationship for Normal Adult Skin
Water
Time for 1st Degree Burn
Temperature °F
(Less Severe Burns)
110
(normal shower temp.)
116
(pain threshold)
116
122
21
40A 120-277 VAC
25A.480 VAC
125VA.PT.DTY.
120-480 VAC
HI
MED
APCOM
INC
30A 120-250 VAC
22A 277 VAC
12.5A 480VAC
125 VA.PT.DTY. 120-480 VAC
Figure 14. APCOM Thermostat
Controls
Time for Permanent
Burns 2nd & 3rd Degree
(Most Severe Burns)
35 minutes
45 minutes
1 minute
5 minutes
LO
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