tekmar 402 House Control Installation User Manual
Page 31
31 of 32
© 2010
D 402 - 09/10
Symptom
Look For...
Corrective Action
No central
heating
Burner symbol on
LCD
If the burner symbol is on the LCD, there is a problem with the boiler. Ensure
the boiler aquastat manual limit is reset to the on position.
WWSD symbol on
LCD
Warm Weather Shut Down (WWSD) is an energy saving feature that prevents
central heating during the summer. Ensure the outdoor temperature reading
is accurate and replace outdoor sensor if necessary. WWSD setting can be
increased if heating is required.
Mix or Boil Calls on
LCD
If there are no Mix or Boil Calls, there are no thermostats calling for heat.
DHW Call on LCD
During DHW tank heating, the central heating may not be heated.
System in AWAY
During AWAY, the thermostats operate at a lower temperature. Locate a ‘User
Switch’ and set to Normal to resume heating.
“MIN” shown
together with boiler
target or boiler
supply on LCD
Boiler is operating below the boiler minimum setting and the mixing valve is
closed or the mix injection pump is operating at low speed. The mixing device
will operate normally once the boiler warms up.
Boiler short
cycling
Burner symbol
cycling on and off
Mixing using variable speed injection pumps requires the balancing valve to
be set correctly. Lack of head pressure can lead the injection pump speed to
ramp up and down.
Single zone over
heating
LCD shows zone on
Thermostats have a differential of +/- 1.5°F of the temperature setting. Due to
the display rounding numbers up, heating can appear on when the temperature
is 2°F above the setting. This is normal operation.
LCD shows zone off
Ensure zone valve terminals measure 0 V (ac). Measuring 0 V (ac) indicates
mechanical zone valve may have failed in open position. Measuring 24 V (ac)
indicates control relay may have failed.
Single zone under
heating
LCD shows zone on
Ensure zone valve terminals measure 24 V (ac). Measuring 24 V (ac) indicates
mechanical zone valve may have failed in closed position. Measuring 0 V (ac)
indicates control relay may have failed.
LCD shows zone off
Check for calls
Frequently Asked Questions (2 of 2)
Item
Setting
OUTDOOR DESIGN
MIX DESIGN
MIX TYPE
MIX MOTOR
BOILER TYPE
BOILER DESIGN
BOILER MINIMUM
BOILER MOTOR
MINIMUM MODULATION
MODULATION DELAY
Item
Setting
FLUSHING
WWSD OCCUPIED
WWSD UNOCCUPIED
DHW MODE
DHW EXCHANGE
DHW OCCUPIED
DHW UNOCCUPIED
SETPOINT
UNITS
Job Record