VES Andover Ltd Eagle Close Chandlers Ford Ind. Est Eastleigh Hampshire SO53 4NF
Tel: 08448 15 60 60 Fax: 02380 261204 E-mail: [email protected] Web: www.ves.co.uk
ecovent
NRG
Air Handling Units
Installation, Operation and Maintenance Manual
8
Continued
On NRG -E units, an electric heater battery (EHB) coil will be installed. Supply to the heater
should be 1ph or 3ph with separate neutrals; confi rmation of this can be found on the unit
nameplate. Cables should be of silicone rubber, fi breglass or of a similar high temperature
insulated type and be installed to current
I.E.E. Regulations
, ensuring a suffi cient earth
connection to the terminal provided. Care should be taken not to overstrain the terminal pillars
as this may permanently damage the elements.
The heater is fi tted with a manual-reset high temperature cutout with normally closed (NC)
terminals and is set to break if the duct temperature rises above 130°C. On unit sizes 3 and above
there is an additional 70°C auto-reset cutout and airfl ow pressure switch situated on the fan plate.
It is important that both cutouts are connected in series with the main contactor coil circuit if the
heater is to be isolated in the event of overheating.
The electrical supply must be isolated before attempting to reset the manual cut-out.
For further information regarding electric heaters please see
VES Ref. ID431
.
If a speed controller is fi tted to the system, it must not stop the fan independently of the control
system, or allow airfl ow to fall below the stated volume on the electric heater battery.
Suitable speed controllers without on/off switches are available from VES Andover.
Where a traditional drain pan is fi tted, please refer to trapping detail manual
VES Ref. ID665
.
Consideration should be given to the height required for the trap to function correctly and that the
unit may need additional base support in order to accommodate this correctly.
Coils should be piped according to any relevant local codes of practice. Where threaded con-
nections are supplied, the only approved method of jointing method is by use of Boss white and
hemp. The thread fi tted to the coil is to be supported at all times whilst making joints. All external
piping is to be supported independently from the coil. Fluid fi lters are recommended.
It is important that water and steam coils are protected against damage from extreme weather
conditions during the winter season. If the water is allowed to freeze in the coil system, damage
may occur potentially bursting pipes and resulting in emergency problems.
Fitting a frost thermostat at the unit inlet and ensuring that boilers run continuously in low
ambient temperatures can prevent this.
Heating coils do not cool immediately when the hot water supply is cut off. The residual heat
must be dissipated to avoid damage. The continuous running of the fan after shutdown resolves
this, by operation of a run-on timer. The recommended length of run-on is
2 minutes minimum
.
On NRG -W units, a Low Pressure Hot Water (LPHW) coil will be installed. The coils are
normally suitable for LPHW at 82°C fl ow and 71°C return temperature. LPHW coils are supplied
as standard with an air vent and drain plug located on the pipe work immediately adjacent to
the coil connections on the AHU. The air vent should be at the highest point, with the drain at
the lowest. The coil should be regularly vented so as to avoid potential air locks, resulting in a
fall off of duty.
It is recommended that a check be made as to whether any treatment is required to the water
supply for prevention of corrosion and scaling of the equipment. Information regarding the
necessary action to be taken can be obtained from the relevant Water Supply Authority.
The unit will have been supplied with connections either left or right-hand side looking in
direction of airfl ow. Please see order acknowledgement for confi rmation of this handing. Should
you need to alter this please consult VES as unit adjustment may invalidate your warranty.
Installation
Electric Heater
Batteries
Coils
Hot Water (LPHW) Coils
Condensate Trapping
4
Important
Caution
Caution
