Controls, Start-Up, Operation, Service and ... - Climayoreo

STAGE
Table 49 — IGC LED Indicators
NOTES:
1. There is a 3-second pause between error code displays.
2. If more than one error code exists, all applicable error codes will
be displayed in numerical sequence.
3. Error codes on the IGC will be lost if power to the unit is
interrupted.
The IGC boards only control the first stage of gas heat on
each gas valve. The second stages are controlled directly from
the MBB board. The IGC board has a minimum on-time of 1
minute.
In modes such as Service Test where long minimum on
times are not enforced, the 1-minute timer on the IGC will still
be followed and the gas will remain on for a minimum of 1
minute.
RELOCATE SAT FOR HEATING-LINKAGE APPLICA-
TIONS — If ConfigurationHEATLAT.M is set to YES,
the supply air temperature thermistor (TemperaturesAIR.T
SAT) must be relocated downstream of the installed heating
device. This only applies to two-stage gas or electric heating
types (ConfigurationHEAT HT.CF=1 or 2).
Determine a location in the supply duct that will provide a
fairly uniform airflow. Typically this would be a minimum of
5 equivalent duct diameters downstream of the unit. Also, care
should be taken to avoid placing the thermistor within a direct
line-of-sight of the heating element to avoid radiant effects.
Run a new two-wire conductor cable from the control box
through the low voltage conduit into the space inside the building
and route the cable to the new sensor location.
Installing a New Sensor — Procure a duct-mount temperature
sensor (Carrier P/N 33ZCSENPAT or equivalent 10-kilo-ohm
at 25C NTC [negative temperature coefficient] sensor). Install
the sensor through the side wall of the duct and secure.
Re-Using the Factory SAT Sensor — The factory sensor is
attached to the left-hand side of the supply fan housing.
Table 48 — Staged Gas Heat Control Steps (HT.ST = 3)
RELAY OUTPUT
Heat 1 Heat 2 Heat 3 Heat 4 Heat 5 Heat 6
MBB-RLY8 MBB-RLY7 SCB-RLY1 SCB-RLY2 SCB-RLY3 SCB-RLY4
IGC1 MGV1 IGC2 MGV2 IGC3 MGV3
63
CAPACITY
%
0 OFF OFF OFF OFF OFF OFF 0
1 ON OFF OFF OFF OFF OFF 25
2 ON ON OFF OFF OFF OFF 33
3 ON OFF ON OFF OFF OFF 50
4 ON ON ON OFF OFF OFF 58
5 ON ON ON ON OFF OFF 67
6 ON OFF ON OFF ON OFF 75
7 ON OFF ON ON ON OFF 83
8 ON ON ON ON ON OFF 92
9 ON ON ON ON ON ON 100
ERROR CODE LED INDICATION
Normal Operation On
Hardware Failure Off
Fan On/Off Delay Modified 1 Flash
Limit Switch Fault 2 Flashes
Fame Sense Fault 3 Flashes
Five Consecutive Limit Switch Faults 4 Flashes
Ignition Lockout Fault 5 Flashes
Ignition Switch Fault 6 Flashes
Rollout Switch Fault 7 Flashes
Internal Control Fault 8 Flashes
Software Lockout 9 Flashes
Disconnect the sensor from the factory harness. Fabricate a
mounting method to insert the sensor through the duct wall and
secure in place.
Attach the new conductor cable to the sensor leads and terminate
in an appropriate junction box. Connect the opposite
end inside the unit control box at the factory leads from MBB
J8 terminals 11 and 12 (PNK) leads. Secure the unattached
PNK leads from the factory harness to ensure no accidental
contact with other terminals inside the control box.
TEMPERING MODE — In a vent or cooling mode, the
economizer at minimum position may send extremely cold
outside air down the ductwork of the building. Therefore it
may be necessary to bring heat on to counter-effect this low
supply-air temperature. This is referred to as the tempering
mode.
Setting up the System — The relevant set points for tempering
are located at the local display under Setpoints:
ITEM EXPANSION RANGE UNITS
T.PRG
T.CL
T.V.OC
T.V.UN
Tempering
Purge SASP
Tempering in
Cool Offset
Tempering Vent
Occ SASP
Tempering Vent
Unocc. SASP
CCN
POINT
DEFAULT
–20-80 dF TEMPPURG 50
5-75 ^F TEMPCOOL 5
–20-80 dF TEMPVOCC 65
–20-80 dF TEMPVUNC 50
Operation — First, the unit must be in a vent mode, a low cool,
or a high cool HVAC mode to be considered for a tempering
mode. Secondly, the tempering mode is only allowed when the
rooftop is configured for staged gas or hydronic heating (ConfigurationHEATHT.CF=3
or 4). Also, if OAT is above
the chosen tempering set point, tempering will not be allowed.
Additionally, tempering mode is locked out if any stages of
mechanical cooling are present.
If the control is configured for staged gas or hydronic heating
and the control is in a vent, low cool, or high cool HVAC
mode, and the rooftop control is in a situation where the economizer
must maintain a minimum position/minimum cfm, then
the evaporator discharge temperature (EDT) will be monitored.
If the EDT falls below a particular trip point then tempering
mode may be called out:
HVAC mode = “Tempering Vent”
HVAC mode = “Tempering LoCool”
HVAC mode = “Tempering HiCool”
The decision making/selection process for the tempering
trip set point is as follows:
If an HVAC cool mode is in effect, then the tempering cool
point is SASP – T.CL.