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16
TWH – Tankless Water Heater Panels
Installation, Operation, and Maintenance
Troubleshooting
Problem
Check / Verify
Possible Cause
Low Temperature Within Room
Misplacement of thermostat location within
room.
Make sure thermostat is not being infl uenced
by an additional heat source, such as lighting
or air duct.
Low temperature setting of the thermostat.
Adjust the temperature setting on thermostat.
The system fails to turn on if the thermostat is
set to high setting
Thermostat may be out of calibration or
defective. Replace thermostat.
The electronic actuator fails to open during a
call for heat
The electronic actuator may be improperly
seated or may be defective. Replace if
necessary.
Low supply mixed fl uid temperature.
Adjust the thermostatic mixing valve to the
appropriate setting.
Wiring from heat source to panel.
Check that the wiring is done properly. Consult
qualifi ed electrician prior to alteration of wiring
between heat source and panel.
Output of heat source is unable to meet
demand of heating system.
Compare output of heat source to the
requirements of the heating system.
The red and green LED’s on the power module
do not light up during a call for heat.
The zone valve controller may be defective
or there is no power being supplied to the
panel or the power module is not on. If this
is so, switch the power module to by-pass
mode. When the front three-way switch is
placed in the “Heat Source Pump Bypass”
position, the green LED will be lit, indicating
that the panel is powered with 110V, and the
Primary pump will run. When the side “Bypass
Radiant Pump” switch is placed in the “ON”
position, the yellow LED will be lit, indicating
that the panel is powered with 110V, and the
Secondary pump will run. This will provide
constant circulation so long as there is still
110V power to the panel.
Circulator is not on during a call for heat. (Use
a stethoscope or similar device to verify)
The power box or circulator may be defective.
When zone valves are installed outside the
panel a qualifi ed electrician should verify 24V
power is supplied to the thermostats and
actuator.
The 24V transformer may have failed. If this
so, switch the power module to Bypass mode.
This will provide constant circulation so long
as there is still 110V power to the panel. Prior
to Bypass mode selection, any zone valves
must be opened manually to avoid dead-
heading of the circulator.
High Temperature Within Room
Check current setting of the thermostat.
Adjust the temperature setting on thermostat
to a lower setting.
High supply mixed fl uid temperature.
Adjust the Thermostatic Mixing Valve to the
appropriate settings.
Installed electronic actuators remain open
after the thermostat is satisfi ed.
An obstruction inside the zone valve is not
allowing the actuator to fully close or the
thermostat is still calling for heat.
Bypass switch(es) may be on.
Check that the front three-way switch on the
power box is in the “ON” position and the side
“Bypass Radiant Pump” switch is in the “OFF”
position.
