33 750-265
DHW high limit
The DHW high limit is a safety limit when Lockout or Recycle & Hold is selected. However, it is not a safety limit when “Suspend
DHW” is selected. The DHW pump control is not a safety function.
CH slow start enable Enable, Disable
This parameter enables or disables the slow start limit function for CH and LL demand
sources. It uses the CH forced rate parameter as the starting point for the slow start. If the
forced rate parameter is invalid or zero and slow start is enabled, then the slow start function
does not occur and an alert is issued.
DHW slow start enable Enable, Disable
This parameter enables or disables the slow start limit function for DHW demand source. It
uses the DHW forced rate parameter as the starting point for the slow start. If this forced rate
parameter is invalid or zero and slow start is enabled, then the slow start function does not
occur and an alert is issued.
Slow start setpoint Degrees or None
If slow start limiting is enabled and the outlet temperature is less than the temperature
provided by subtracting this number of degrees from the setpoint, then slow start rate limiting
is effective. Whenever the outlet temperature is above this value, slow start limiting has no
effect.
Slow start ramp RPM or % Per Minute
When slow start limiting is effective, the modulation rate will increase no more than the
amount per minute given by this parameter.
Although provided as a per-minute value, the R7910A will calculate and apply this as a
stepped function using a step duration of 10 seconds.
Table 15. Limits and Rate Override: Slow Start Limit Parameters. (Continued)
Parameter Comment
Table 16. Limits and Rate Override: Outlet High Limit.
Parameter Comment
DHW high limit enable Enable, Disable
This parameter enables or disables the DHW high limit function. It must be disabled when the
DHW input is used as a switch to indicate DHW demand.
DHW high limit setpoint Degrees or None
If DHW high limit enable is enabled and the DHW temperature reaches the value given by
this parameter, then a response will occur.
DHW high limit response Lockout, Recycle & Hold
This parameter selects the response.
If lockout is selected then the burner control locks out.
If Recycle & Hold is selected then the burner control recycles and holds until the DHW
temperature falls below the DHW high limit temperature minus 5°F.
DHW high limit pump inhibit If DHW high limit enable is enabled then whenever the DHW high limit has been reached the
DHW pump will be forced off. It will remain off until the DHW input temperature is lower than
the DHW high limit temperature minus 5°F. The DHW high limit pump inhibit function is not a
safety function.
To Next Page
Loading...
Need help?
General
