Lochinvar CREST 3 - Manual (Page 20)

1
Service
20
Service Manual
Outdoor Air Shutdown Differential
The outdoor air shutdown differential parameter is the
number of degrees below parameter C5 the outdoor air
temperature must go before the boiler will respond to a SH
demand. This parameter can be changed by the installer by
accessing parameter C6.
Boost Time
The boost time parameter sets the amount of time that must
elapse with a SH demand before the water temperature
calculated set point will be increased. This parameter can
be changed by the installer by accessing parameter C7.
Boost Temperature
If a SH demand lasts longer than the programmed boost
time delay setting (C7) and there have been no HWG
demands, the control will increase the water temperature
set point by the amount in this parameter. If the SH
demand continues through another time period, the set
point will be increased again. This will continue until
either the SH demand ends, a maximum of 20 increases
has occurred, or the maximum set point has been reached.
Once the SH demand has been satisfied the set point will
revert back to its calculated setting. The boost temperature
can be changed by the installer by accessing parameter C8.
Shift OA Reset Curve
The shift reset curve parameter shifts the actual set point above
or below the calculated set point by the number of degrees in
this parameter. This parameter can be changed by the installer
by accessing parameter C9.
D: Ramp Delay
Ramp Delay (Enable / Disable)
This parameter allows the installer to enable or disable the SH
ramp delay by accessing parameter D1.
SH Ramp Delay
The SMART TOUCH control can be programmed to limit
the firing rate for a fixed period of time at the start of a space
heating demand. There are six (6) possible limits, each with
their own time delay. The first limit applies as soon as the
burner starts. Once its time delay expires, the second limit is
applied and its timer begins. The control steps through these
limits until the 6th (sixth) limit expires. Note, however, that
the 6th limit will also limit the rate for the rest of that heat
demand. The installer can adjust the firing limits and time
delays by accessing parameters D2 through D13.
Figure 1-7 Ramp Delay Interval