Grant DuoWave Direct 170, Installation & User'S Instructions

Electrical Installation

15

All electrical wiring must be carried
out by a competent person and in
accordance with the 

current I.E.E.

Wiring Regulations. 

The control equipment supplied will
ensure that the cylinder functions safely.
From an economic and convenience
point of view, it is intended that these
controls operate in conjunction with
other control packages for example “S”,
“W” or “Y” plan type systems, which
incorporate a programmable time clock,
etc.

5.1 Immersion Heater 

All cylinders are supplied fitted with
either one or two immersion heaters,
dependent on the model and capacity.

Each 3kW 230V 50Hz-immersion
heater should be wired in accordance
with the instructions given in Figure 5-1.

The cable 

must

be routed through 

the strain relief bush. The control
thermostat is pre-set at approximately
60°C. The immersion heater conforms
to EEC Directive 76/889 for radio
interference and complies with EN
60335-2-73.

Installation and wiring instructions for
the immersion heater are supplied with
each unit. Follow the wiring instructions
connecting the live, neutral and earth as
indicated. 

The unit must be permanently
connected to the electrical supply
through a double-pole isolator. A safety
cut-out is also incorporated within the
thermostat and is factory set to operate
at 80°C ± 5°C. 

IMPORTANT

Before resetting the safety cut-out or
altering the thermostat setting, isolate
electrical supply to the unit prior to
removal of the cover. Investigate and
identify the cause of the cut-out
operation and rectify the fault before
manually resetting the cut-out by
pressing in the reset button. Ensure the
cover to the immersion element is
replaced correctly and the retaining nut
is fitted. Finally switch the mains
electricity supply back on.

Figure 5-1:

Immersion heater wiring

connections

= Earth (Green/Yellow)

= Live (Brown)

= Neutral (Blue)

Temperature
control dial

Reset

This appliance 

must

be earthed.

!

WARNING

The manual re-set high limit
thermostat must not under any
circumstances be bypassed. This 
is pre-set to 80°C and to prevent
nuisance tripping the control
thermostat should always be left in
position 4.

!

WARNING

d) The BEAB approval certification on

this immersion heater only applies if
a Cotherm TSE rod type thermostats
is used. The temperature setting of
the control thermostat should
always be left in position 4.

5.3 Dual Thermostat (Indirect
Temperature Control) 

For the Indirect models two Dual
Thermostats (each a combined control
and high limit thermostat) are supplied
separately with the unvented hot water
safety kit. One is fitted into the upper
sensor pocket in the cylinder (see
Figures 2-4 to 2-6 for position) to
control the operation of the boiler or
heat pump primary coil. The second is
fitted in the lower sensor pocket to
control the operation of the Solar coil.
For Direct models only one Dual
Thermostat is supplied to be fitted in
the lower sensor pocket.

The control thermostat has an
adjustment range between 25°C and
65°C, however it is recommended that
it is set to 60°C. The overheat
thermostat incorporated within the dual
thermostat will operate at 90°C. 

5.4 2-Port Valve (Indirect only)

To comply with regulations governing
the installation of indirect unvented
cylinders, a 2-port motorised valve
must be fitted in the primary flow to
prevent gravity circulation when the
boiler switches off. Your Grant
DuoWave unit has been supplied with a
2-port motorised valve, which will act
as a positive energy cut-out should the
safety cutout operate. Should this
happen the motorised valve will operate
and close down the primary flow to the
cylinder. The valve should be wired in
accordance with Figures 5-3, 5-5,
5-7, 5-9 or 5-11 depending on system
design, to comply with current
legislation.

For an air source heat pump (other than
a Grant Aerona heat pump) consult the
heat pump manufacturer for connection
details.

This motorised valve will also control
the temperature of the domestic stored
water via the cylinder thermostat, which
is located in the upper dual thermostat.
The unit should be installed on a “W”,
“S” or “Y” plan system as shown in
Figures 5-2, 5-4 and 5-6.

5.2 Immersion Heater Wiring
Instructions 

a)

Ensure the main’s voltage
corresponds to the voltage rating 
of the immersion heater as shown
on the rating label on the terminal
cover.

b) The immersion heater is factory

fitted to the cyinder. If the
immersion heater needs to be
replaced it must be fitted to the
cylinder using the gasket provided
on the unit. Use a shaped spanner,
Stillsons or pipe grips should not be
used. The use of sealing compound
is not recommended.

c)

Wire the immersion heater in
accordance with the wiring diagram
(Figure 5-1). It should be wired
through a double pole isolator 
switch or controller, with a minimum
break capacity of 13 amp having
contact separation of at least 3
mm, using 1.5mm sq. flexible cable,
85°C rubber insulated HOFR
sheathed, to comply with BS 6141
table 8 and must be fully earthed.

5 

Electrical Installation