Knight 285, Service Manual, Page: 12 / 44

1
Service
12
Service Manual
1
Service
Sequence of operation
(continued)
Table 1 (continued from previous page) Sequence of operation - space heating and DHW
O OP PE ER RA AT TIIO ON N D DIIS SP PL LA AY Y
8. 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 modulating based on the space heating
set point. 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.
BLR: SH 41% RATE
OUT: 123.0F(129)
9. Once both calls for heat are satisfied, the control will turn off the
burner. The blower will remain on for the 10 second postpurge
cycle. Any pumps that are running will continue to run for their
respective pump delay times, then turn off.
BLR: POSTPURGE
OUT: 127.4F(129)
10. Boiler pump off, system pump continues its delay if longer.
BLR: Standby
OUT: 124.7F(129)
11. System pump off.
BLR: Standby
OUT: 122.9F(129)