IBC V-10, Руководство по эксплуатации

Страница: 21 / 36

17
OPERATING INSTRUCTIONS
V-10 TOUCH SCREEN BOILER CONTROLLER
3. Initial Delay: The number of minutes after the Primary load must initially be
serviced before the boiler can add a Secondary load. A sufficient amount of
time should be allowed for the Primary load to stabilize before the boiler adds
the Secondary load.
4.
Off Delay: When the secondary load is added into combination service it
is expected that the supply temperature could briefly go below the normally
allowed temperature range for the Primary load. The Off Delay is the number
of minutes after the loads have been initially combined that the loads will
continue to be combined regardless of an under-temperature condition.
The Off Delay setting should be reasonably long enough to allow the boiler
to drive the supply temperature up within the Primary load’s target supply
temperature range. The loads will be uncombined if the under temperature
condition persists after the Off Delay time. If the supply temperature exceeds
the requirements for either the Primary or Secondary load the loads will be
uncombined immediately.
5.
Retry Delay: If the boiler has to remove the Secondary load from combined
service because Load Combining conditions have been violated the Retry
Delay is the number of minutes the boiler will wait before attempting to add
the Secondary load back into combination service.
6.
Maximum Throttle: Maximum Throttle % is the percentage of the boiler’s
maximum heat output for which Load Combining will be allowed to begin.
The Secondary Load will not be added into combined service if the boiler’s
output is higher than this value. The Maximum Throttle % has no effect
once the loads have been combined.
1.7.2.1 CONSIDERATIONS FOR COMBINING LOADS
The Primary and Secondary loads must have compatible temperature parameter
settings, or the Secondary load cannot be combined for service. The type of load
generally doesn’t matter, as long as the target temperature requirements for the
loads to be combined are similar.
Load Combining does not interfere with the normal Load Priority scheme
implemented by the boiler. Therefore, the Secondary load must be configured with
a lower initial priority than the Primary load (a priority difference of at least 15 is
recommended). If the Secondary load’s running priority becomes higher than the
Primary load, then it will be serviced in the normal priority rotation, just as if the load
were not combined. The Primary load will be dropped, and the Secondary load will
be serviced in the normal priority rotation. The priority scheme also means that the
Load Combining will only occur while the Primary Load is the active load. The same
would apply if an uncombined load’s priority became higher than the Primary’s. The
Primary load, and therefore the Secondary load if in combination service at the time,
would be dropped and the uncombined load serviced in the normal priority rotation.
Compatibility temperature ranges are the load’s target temperature, +/- the
differential temperature (the load’s minimum and maximum supply temperatures).
Note that any system or load temperature limits will still be in effect.
It should be noted that in the case of Reset Heating or External Control loads,
the target temperature is dynamic. So it is possible that as outdoor and/or indoor
temperatures change, reset and external control heating loads could drift in
and out of compatibility for Load Combining. See IBC Technical Note: Load
Combining for further details.