72
Fan Status Monitoring
GENERAL — The N Series ComfortLink controls offer the
capability to detect a failed supply fan through either a duct
static pressure transducer or an accessory discrete switch. The
fan status switch is an accessory that allows for the monitoring
of a discrete switch, which trips above a differential pressure
drop across the supply fan. But for any unit with an installed
duct static pressure sensor, it is possible to measure duct pres-
sure rise directly, which removes the need for a differential
switch.
SETTING UP THE SYSTEM — There are two configura-
tions of concern located in Configuration
UNIT. See
Table 48.
Table 48 — Fan Status Monitoring Configuration
Fan Stat Monitoring Type (
SFS.M) — This configuration se-
lects the type of fan status monitoring to be performed.
0 - NONE — No switch or monitoring
1 - SWITCH — Use of the fan status switch
2 - SP RISE — Monitoring of the supply duct pressure.
Fan Fail Shuts Down Unit (
SFS.S) — This configuration
will allow whether the unit should shut down on a supply fan
status fail or simply alert the condition and continue to run.
YES — Shut down the unit if supply fan status monitoring
fails and send out an alarm.
NO — Do not shut down the unit if supply fan status monitor-
ing fails but send out an alert.
SUPPLY FAN STATUS MONITORING LOGIC — Regard-
less of whether the user is monitoring a discrete switch or is
monitoring static pressure, the timings for both techniques are
the same and rely upon the configuration of static pressure
control.
The configuration which determines static pressure control
is Configuration
SP
SP.CF. If this configuration is set to 0
(none), a fan failure condition must wait 60 continuous seconds
before taking action. If this configuration is 1 (VFD), a fan fail-
ure condition must wait 3 continuous minutes before taking
action.
If the unit is configured to monitor a fan status switch
(SFS.M = 1), and if the supply fan commanded state does not
match the supply fan status switch for 3 continuous minutes,
then a fan status failure has occurred.
If the unit is configured for supply duct pressure monitoring
(SFS.M = 2), then
• If the supply fan is requested ON and the static pressure
reading is not greater than 0.2 in. wg for the time clarified
above, a fan failure has occurred.
• If the supply fan is requested OFF and the static pressure
reading is not less than 0.2-in. wg for the time clarified
above, a fan failure has occurred.
Dirty Filter Switch — This unit is equipped with several
filter stages. It is important to maintain clean filters to reduce the
energy consumption of the system. This unit is designed to pro-
vide several ways to achieve this goal. Table 49 shows the nine
configurations for filter monitoring in this unit. If the configura-
tion for either the main or final filter is set to 0-Disable then the
input is set to read clean all the time. There are several controls
which need to be used in conjunction with the filter configura-
tion so that each corresponding setting will operate correctly.
The fault status timer is a parameter which sets the number
of minutes the filter status must be in a fault state before the fault
latch is closed. To set the fault time use Configuration
IAQ
FLTC
FS.FT the range is between 0 and 10 min-
utes. The default for this parameter is 2 minutes.
Filter types (MF_TYP, PF_TYP) and final resistance
(MF_FR, PF_FR) are used for the Delta Pressure and Predic-
tive Life configurations for the main and post filter. The final re-
sistance will be automatically set when the filter type is selected.
After selecting a filter type it is possible to change the filter final
resistance. Settings for filters based on Table 49 and 50 for main
and post filters.
Table 49 — Main Filter Types
Table 50 — Final Filter Types
To change the filter type for the main filter use Configura-
tion
IAQ
FLTC
MF.TY set between 0 and 6 according to
the main filter type table. To change the filter type for the final
filter use Configuration
IAQ
FLTC
PF.TY set the be-
tween 0 and 6 according to the post filter type table. To adjust
the final resistance for the main filter after a filter type has been
selected use Configuration
IAQ
FLTC
MF.FR and set
from 0 to 10. To adjust the final resistance for the post filter use
Configuration
IAQ
FLTC
PF.FR and set between 0 and
10.
1 = Switch
— If the Filter configuration for either the main or
post filter is set to 1 (Switch) then a filter status switch should be
installed. The monitoring of the filters is based on a clean/dirty
switch input.
Monitoring of the main and post filter status switches is dis-
abled in the Service Test mode and when the supply fan is not
commanded on. If the fan is on and the unit is not in a test mode
and either the main or post filter status switch reads "dirty for a
user set continuous amount of time, an alert is generated. Re-
covery from this alert is done through a clearing of all alarms or
after cleaning the filter and the switch reads clean for 30 sec-
onds.
ITEM EXPANSION RANGE CCN POINT
SFS.S Fan Fail Shuts Down Unit Yes/No SFS_SHUT
SFS.M Fan Stat Monitoring Type 0 - 2 SFS_MON
MAIN FILTER TYPE
(MF_TYP)
DESCRIPTION
MAIN FILTER FINAL
RESISTANCE
(MF_FR)
0
Std 2 in. MERV 1
1
4 in. MERV 8 1
2
4 in. MERV 14 1.5
3
12 in. MERV 14
Bag with 2 in. pre’s
2
4
12 in. MERV 14
Bag with 4 in. pre’s
2
5
19 in. MERV 15
Bag with 2 in. pre’s
2
6
19 in. MERV 15
Bag with 4 in. pre’s
2
7
12 in. MERV 14
Cart with 2 in. pre’s
2.5
8
12 in. MERV 14
Cart with 4 in. pre’s
2.5
9
Strion Air 2
MAIN FILTER TYPE
(MF_TYP)
DESCRIPTION
MAIN FILTER FINAL
RESISTANCE
(MF_FR)
0
None 0
1
12 in. MERV 14
Cart with 2 in. pre’s
2.5
2
12 in. MERV 14
Cart with 4 in. pre’s
2.5
3
19 in. MERV 15
Bag with 2 in. pre’s
2
4
19 in. MERV 15
Bag with 4 in. pre’s
2
5
12 in. MERV 17
Bag with 2 in. pre’s
3
6
12 in. MERV 17
Bag with 4 in. pre’s
3
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