CleaverBrooks CFC-500 Operation, Service And Parts Manual page 168

CB FALCON
Parameter
Delta-T inlet/exch degrees
Delta-T exch/outlet degrees
All of the Delta-T functions will share the following parameters:
Delta-T response
Delta-T delay
Delta-T retry limit
Delta-T rate limit enable
Delta-T inverse limit time
Delta-T inverse limit response
T-Rise
A limit may be imposed on the rate of temperature rise for
either the outlet or exchanger temperature, or both.
Parameter
Outlet T-Rise enable
Exchanger T-Rise enable
750-265
Table 18. Delta-T Limit Parameters. (Continued)
Degrees, none
Degrees, none
This is the temperature at which a Delta-T response occurs, measured as the signed value
(hi-lo) if the result is negative then it is treated as zero (inversion detection may be enabled to
handle this, but that is a different function which does not use this parameter).
Lockout, Recycle & Delay, Recycle & delay with retry limit
This specifies the type of response that occurs when the Delta-T degrees threshold is met.
The Recycle & delay with retry limit will limit the number of retries as specified by the Delta-T
retry limit.
mm:ss, none
Specifies the delay time that occurs whenever a recycle occurs due to a Delta-T or Delta-T
inverse event occurs and the specified response includes "Recycle..." The burner will remain
in the Standby Hold condition until the delay expires.
number of tries
If either the Delta-T response or the Delta-T inverse limit response specify a retry limit, then
any recycles due to reaching the corresponding response threshold are counted. If this count
ever exceeds the "n" value, then a lockout occurs.
A single counter is used for Delta-T and Inversion Detections, so it could be that different
causes occurred to make the counter exceed its final retry limit count of "n" Only the final
event that causes the count to exceed the retry limit is annunciated as the cause of the
lockout, although each of the reasons for recycling abnormally always generates an alert, as
usual, so the presence of other events will be visible in that log.
The retry counter is cleared when a normal recycle (burner turn-off) occurs due to satisfying
all of the demands.
A limit of zero is equivalent to selecting "lockout."
Disable, Enable
Disable then no modulation limiting occurs as the delta-T threshold is approached.
Enable, then the Stepped Modulation Limiting feature is active for Delta-T.
mm:ss or None
This provides the time limit during which inverted temperature is tolerated when one of the
two inverse detection option is enabled.
Lockout, Recycle & Delay, Recycle & delay with retry limit
If temperature inversion detection is enabled and it persists for the time given by the Delta-T
inverse limit time, then the response described by this parameter occurs.
The delay time used is the time specified by the Delta-T delay and the retry limit is the count
specified by the Delta-T retry limit.
Table 19. T-Rise Parameters.
Disable, Enable
This enables/disables temperature rise detection for the outlet sensor S3 (J8 terminal 8).
Disable, Enable
This enables/disables temperature rise detection for the heat exchanger sensor S9 (J9
terminal 6).
If this selection is "Enable" then the Stack Connector Type must be either "10K single non-
safety NTC" or "12K single non-safety NTC." If this condition is not met then a lockout occurs
because the exchanger input requires using the Stack sensor as two separate sensors. Stack
being S8 (J9 terminal 4) and heat exchanger being S9 (J9 terminal 6).
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