Lochinvar 402 - 2072 Service Manual page 10

1
Service
Sequence of operation
Table 1A_(continued from previous page) Sequence of Operation - Space Heating and DHW
OPERATION
9. If the DHW thermostat remains on for more than 30 minutes,
and the space heating call for heat is also on, then the
control will turn on the boiler pump, turn off the DHW pump
after 2 seconds, and resume firing based on the space
heating setpoint. As long as both the space heating and
DHW calls for heat remain active, the control will switch
back and forth between the two modes until one of them is
satisfied.
10. Once both calls for heat are satisfied, the control will turn
off the burners.
30 second postpurge cycle. Any pumps that are running
will continue to run for their respective pump delay times,
then turn off.
11. Boiler pump off, system pump continues its delay if
longer.
12. System pump off.
10
Copper-fin II/IIE Boiler and Water Heater
The blower will remain on for the
DISPLAY
HTR: RUN STG 12
OUT: 123.0F(129)
HTR: POSTPURGE
OUT: 127.4F(129)
HTR: Standby
OUT: 124.7F(129)
HTR: Standby
OUT: 122.9F(129)
Service Manual