Page 12
Section 4: Electrical
OVER-TEMPERATURE CUT-OUT
This immersion heater is fitted with a Cotherm type TSR
thermostat that incorporates an independent non-self-
resetting over-temperature cut-out to prevent excessive water
temperatures.
The reset pin is located in a small opening to the side of the
control dial and indicated by small triangle with the word ‘safety’.
Refer to Figure 4-4.
In normal operation the reset pin will be approximately 2-3mm
below the surface of the plastic thermostat housing.
Should the over-temperature cut-out operate, the reset pin will be
pushed up to become level or slightly above the surface of the
housing.
To reset the over-temperature cut-out:
•
Isolate the volumiser/header and immersion element from the
mains electrical supply.
•
Wait for the temperature in the volumiser/header to fall
sufficiently.
•
Using a suitably sized implement, push the reset pin using
hand pressure only to return it to its normal operating
position.
! WARNING !
Ensure the volumiser/header and immersion heater is
isolated from the mains before attempting to reset to
over-temperature cut-out.
If the immersion heater needs to be replaced it must be fitted to
the volumiser/header using the gasket provided on the unit. Only
use a correctly shaped spanner. Stilsons or pipe grips should NOT
be used. The use of sealing compound is not recommended.
! WARNING !
Always ensure that the immersion heater cap is not
covered.
4.4
ELECTRICAL CONNECTIONS BETWEEN
LEAD AND SUPPLEMENTARY HEAT
PUMPS
When using two Aerona³ heat pumps connected to the volumiser/
header, one of the two (the supplementary unit) will be controlled
by the other (the lead unit).
The lead unit can be used to provide both Heating and DHW, but
the supplementary unit will be used only for Heating.
Refer to Figure 4-5 below for details of the electrical connection
between the two heat pumps.
Scale: NTS
Paper Size: A4
Project Title: Aerona³ ASHP Lead to Back-up unit connection details
Drawing Set: Aerona³ Wiring Schematics
Status: Approved
Rev Date: 20/01/22
Drawn By: CG
Checked By: PS & NS
Dwg. No. HPWS0026
Revision: 1.1
This drawing and its content is subject to copyright. Use other than for its original intended purpose must be arranged with an employee of
Grant UK Ltd.
Hopton House, Hopton Industrial Estate, Devizes, Wiltshire, SN10 2EU, tel; 01380 736920
Revision Details:
1.1 20/01/22 Approved
ASHP Terminals
N
41
42
43
44
51
52
45
46
47
48
49
50
N.C.
- Lead Unit -
ASHP Terminals
1
2
3
4
5
6
7
8
17
18
19
20
21
22
23
24
25
Aerona
³
Heat Pump
3 2 1
1 2 3 4
RL1
RL2
RL3
DHW
N
P
CH
Grant EP002 Heat Pump Interface
Common (Red)
Link
Heating (Blue)
Grant Aerona³ ASHP
Remote Controller
- Supplementary Unit -
Aerona³
Heat Pump
Figure 4-5:
Wiring connections between lead and supplementary heat pumps
