August / 2014
Page 11
DEX & DBX Installation, Maintenance and User Instructions V1.05
Commissioning
To prevent damage to the appliance, the instantaneous water heater must be
purged of air before using it for the first time.
PURGING
Before connecting the electrical supply, open and close the hot water tap until the water
runs smoothly and no more air emerges.
NOTE! Every time the appliance is drained (e.g. after work on the plumbing system,
if there is a risk of frost or following repair work), the heater must be purged in
this way before reconnecting the power supply.
WARNING!
This appliance must be earthed.
Model DEX only
• The maximum power rating of the appliance can be selected from 18, 21, 24 or
27kW (8.8 or 11.0kW for DEX12) at the time of installation. The maximum power
rating should only be selected with reference to the technical data on page 4, after
ensuring that correct cable sizing and fuse protection is in place and with regard to
local site conditions and electrical regulations.
• This should only be carried out by a competent person familiar with instantaneous
water heaters.
1. Switch on the power supply to the appliance. The digital display will light up.
Fig 9
(3-phase model shown)
S
CAUTION
Electrical connection from above
(not applicable to model DEX12)
Check the power supply is switched off prior to electrical
connection!
1
. Open the prepared breaking point (S) in the upper part of the
appliance by pressing with a blunt instrument (e.g. Screwdriver)
2. Open the cable grommet to slightly smaller than the cable size to
ensure optimum protection against water ingress. Fit the grommet
into the cable opening. N.B. The cable grommet must be used.
3. Strip the cable 6cm above the point where it emerges from the wall.
Support the appliance while the cable is routed through the grommet.
4. Unscrew the terminal block fixing screw. Reposition the terminal
block on the upper mounting and secure with the fixing screw.
5. Fit the connecting cables into the terminal block according to
the wiring diagram on page 9. Ensure all connections are fully
tightened and secure.
6. The appliance must be earthed.
7. Re-fit the appliance cover and secure with the fixing screw before
re-fitting the fascia panel.
