26
26. 01. 22. Document Number 671829
Nuaire | Western Industrial Estate | Caerphilly | CF83 1NA | nuaire.co.uk
BPS H-AT
Installation Manual
11.0 FROST COIL INSTALLATION (OPTIONAL
ANCILLARY)
11.1 LPHW Frost Coil
LPHW frost coils are fitted with a frost stat on the air in side and an on/
off 230v valve actuator (Unit size 32 & 42 are NOT provided with valve
and actuator). If the frosts stat switches to a frost condition, the valve
actuator will open. The valve will open whether the fans are running
or not. This is for pipe freeze protection. The LPHW section requires its
own supply in order to power the valve actuator.
11.2 Wiring - LPHW Frost Coil Unit Sizes 05 - 20
External
Rotary
Isolator
N
L1
LPHW Frost Heater Supply
(Overcurrent protection by others)
Recommended Frost
Temperature Setting 4°C
Heater Temperature
Setting
°C
-8
-2
2
8
38
Wiring - LPHW Frost Coil 07 - 42
11.3 Electric Heater Frost Coil
Electric heater frost coils are fitted with its own internal control panel.
The control is powered by a 400Vac 50Hz 3 phase & Neutral supply.
This must be isolated local to the unit and fitted with appropriate
overcurrent and fault protection. It connects to the main unit via “plug
and play” interconnecting looms. (See interconnection section for
details). No external connections are required. Electric heater elements
are protected by a fail-safe over-temperature switch which will
disconnect the heater supply if a temperature of 80°C is reached. Once
the elements cool, the switch will reset but a power cycle is required to
reset the heater supply contactor.
The frost coil is fitted with a burst fired controller with integral set
point, air off thermistor, air in frost stat, thermal cut-out and contactor.
The burst fired controller is only enabled if the frost stat reads a frost
condition, the over-temperature cut-out is healthy AND a 24vac fan
run signal is received from the main control panel. Once enabled the
burst fired controller will increase heating output to achieve the set
point set by the physical dial on the unit.
11.4 Wiring - Electric Heater Frost Coil Unit Sizes 05 - 20
External
Rotary
Isolator
N
L1
Electric Heater
Power Supply
L2
L3
Recommended Frost
Temperature Setting 4°C
Heater Temperature
Setting
°C
-8
-2
2
8
39
Wiring - Electric Frost Coil 07 - 22
11.5 Electrical Supply FLC’s
‡ Double electric heater models require separate supplies for two
heater sections, each with an appropriate overcurrent current
protection device.
Unit Size
Electric Frost Heater
FLC (Anciliary)
LPHW Frost Coil FLC
(Anciliary)
B*05H/**AT
17.5 A
0.1 A
B*10H/**AT
35 A
0.1 A
B*15H/**AT
52.5 A
0.1 A
B*20H/**AT
52.5 A
0.1 A
