Velocity Shadow Series, Installation And Operating Instructions Manual

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FIGURE 12.0: CONTROL PANEL
LH (”Done”/”Reset”) RH (“Next”)
UP
DWN
Default Mode = User Mode
To Reach Set‐up Mode: Press and hold both UP and DWN for 3s
To reach Diagnostic Mode: Press and Hold LH and RH for 3s.
When Odr is on, and when the boiler is responding to a call for space heat, the target water temperature will adjust downward
(within certain limits) as the outdoor temperature increases. The graph in Figure 12.3 shows how the target water temperature
changes with outdoor temperature. This control strategy increases system effi ciency by keeping the water temperature closer to
the minimum value needed to heat the building based on the current outdoor air temperature.
Figure 12.3 shows the default reset curve; the ends of this curve can be changed by adjusting the CH Set point, LBT (“Low
Boiler Temp”), HOD (“High Outdoor Temp”), and LOD (“Low Outdoor Temp”). The ideal values for these four settings depend
upon the type of radiation in the building. The default values will generally provide adequate comfort regardless of the type of
radiation used.
The default ODR setting is “On”, but it can be turned off by pressing either the UP or DWN keys. The outdoor reset function
should not be turned off unless at least one of the conditions listed in the “IMPORTANT” box below is met. If ODR is turned off,
the screens for adjusting LBT, HOD, and LOT are not visible.
LBT (S3) – Low Boiler Temperature. See Figure 12.3 and the Odr discussion above.
HOD (S4) – High outdoor temperature. See Figure 12.3 and the Odr discussion above.
LOD (S5) – Low outdoor temperature. See Figure 12.3 and the Odr discussion above.
dH (S6) – Domestic hot water (DHW) set point. This is the set point of the boiler supply temperature during a call for DHW.
Control of the potable water temperature itself is accomplished using the thermostat on the storage type indirect water heater.
ASC (S7) – Anti short cycle time. This setting can be used to enforce a minimum period of time between calls for CH. Default is
zero.
IMPORTANT
This boiler is equipped with a feature that saves energy by reducing the boiler water temperature as the
heating load decreases. This feature is equipped with an override which is provided primarily to permit the
use of an external energy management system that serves the same function. THIS OVERRIDE MUST
NOT BE USED UNLESS AT LEAST ONE OF THE FOLLOWING CONDITIONS IS TRUE:
• An external energy management system is installed that reduces the boiler water temperature as
the heating load decreases.
• This boiler is not used for any space heating.
• This boiler is part of a modular or multiple boiler system having a total input of 300,000 BTU/hr or
greater.