NorAire NC-FE series, Инструкция по установке и эксплуатации

Страница: 33 / 64

05/16/2014 31 NI216
Internal pump – the normal operation of the pump is from a W or Y IN and defrost control wire. The pump is
on for 30 seconds to stabilize various temperature sensors before HP-Y output. Also, the pump continues for 60
seconds after W or Y IN is dropped.
ƒ
A hardware tab labeled PUMP (T6) activates the pump relay when this tab is jumpered to R voltage.
SW OVER setup dial switch – typically do not use positions 7 or 0. See Field Setup section.
Backup or auxiliary electric – this is active for OT temperatures below SW OVER setting, front panel backup
switch, mode sequence charts, and Hard Hold. The continued heating provisions include:
ƒ
Mode A – not possible
ƒ
Mode B – internal Electro-Boiler
ƒ
Mode C – possible external boiler plumbed at a buffer tank and activated by NorAire control board
backup, COM, and NO tabs
Comment – except for no flow sensing, there are no other backup SERVICE or ALARM limits. The
Electro-Boiler has its own target temperature/modulation, auto reset hi-limit, and manual reset hi-limit
installed at the boiler vessel. It is assumed the external boiler will have its own temperature control and
limits.
Front panel and control board LED’s – the Operation Indicators section with the various LED’s will provide
significant diagnostic information. The NorAire controller (with the PC software CD) provides more than
typical HVAC products. Some additional tips associated with the Operation Indicators page:
ƒ
POWER ON also provides bad sensor information. This is not an all exclusive bad sensor diagnostic. It
simply means software cannot detect a value, see below. It does not diagnose an incorrect value.
ƒ
HP ODU or AQUASTAT – this represents a hardware voltage, the same as taking a voltage reading on
HP-Y screw, W screw, or Y screw. This is handy knowing the primary externals coming in and out of
the control board.
ƒ
STATUS – this indicates the software mode, it displays the condition without consideration for W, Y, or
Utility Interrupt inputs. Also, fast pulsing with the same power-on pulsing means the mode switch is in
D position, which is not used.
ƒ
SERVICE – reference the factory default setup limits. Low water flow is calculated 5 minutes after
each new W-IN. It does not repeat, but there is an initial cycle off and on, with the service light
indicating this condition.
ƒ
ALARM – this could lead to a Hard Hold, see Control Sequence Information section.
-
FREEZE PROTECT, count 1 – this is critical, at 38° F (3° C) coming out of the coax heat
exchanger, to make sure the heat exchanger does not freeze and bust. Warranty does not cover
leaking or busted heat exchanger.
-
COMPRESSOR NO RESPONSE, count 2 – this is critical for preventing building freeze-up
and automatic backup. Two detection methods are employed:
ƒ
Hardware, ODU fault wire (continuous) – this should be connected to E-tab and PC
download “compressor no response diff” should have digit “0” entry.
ƒ
Internal sequence calculation – during a W or Y input, every 5 minutes the supply
temperature (STc) is compared to return temperature (RT). The PC download has a
selected difference value, if the supply to return relationship is less than this value the
control board sequence assumes the ODU is “dead”.
ƒ
Comment – in order to prevent the ODU from continually resetting, the HP-Y is not
dropped during the IDU internal alarm retry sequences.
-
Return < 42° F, count 3 – this is an internal test at the hydronic return water sensor, 20 seconds
after outputting HP-Y1. A shutdown and alarm is declared for water too cold coming into the
heat pump evaporator coil. Refrigerant low pressure danger and possible low pressure cutout
could result if the compressor suction is too low. This test and monitor prevent damage to
compressor.
-
NO WATER FLOW, count 4 – this is a direct result of the water inlet pipe hardware safety flow
switch. There is a 20-second delay after pump start (W or Y IN). See Control Sequence section.
Comment – if mode B or C and a declared Hard Hold, the backup internal boiler or external backup
contact closure responds to a W IN.