Grant Aerona - Appendix D: Smart Immersion Relay; Wiring the Smart Immersion Relay; Smart Immersion Functionality Overview; Legionella Protection Scheduling

Appendix D: Smart Immersion RelayPage 48
D.1 GENERAL
The Grant Smart Immersion relay is designed to provide a switch
relay between the Grant Aerona Smart Controller and an installed
immersion heater. The Grant Aerona Smart controller utilises the
relay to provide a Legionella protection regime.
An additional Immersion relay will be required to control a
supplementary immersion heater tted in a volumiser, bu󰀨er or
Low Loss header.
D.2 WIRING
The Grant Aerona Smart Immersion relay is connected to H1
(Terminals 19 and 20) or H2 (Terminals 21 and 22). H1 is for
use with an immersion heater installed in a external volumiser or
Low Loss header, while H2 is dedicated for the DHW immersion
heater. (Refer to Section 5 for Terminal schematics)
A secondary power source independent of the Grant Aerona
Smart controller to activate the immersion heaters must be
provided for each relay used.
D.2.1 DHW CYLINDER IMMERSION HEATER
Connecting the Smart Immersion relay to a DHW immersion
heater will provide a legionella protection regime. Refer to Section
D.3 for further guidance.
A switch (MCB) is provided to manually override the relay (only to
be activated by a competent person). This will allow the cylinder to
be heated by the immersion heater only should there be a failure
of the heat pump and/or Grant Aerona Smart controller. Refer to
Figure D-1 for Dual voltage example with external switch.
D.2.1 SUPPLEMENTARY IMMERSION HEATER
Connecting the Grant Aerona Smart controller to a external
volumiser or Low Loss header can provide supplementary
assistance to meet a space heating demand.
Refer to Figure D-1
for additional wiring requirements when connected in conjunction
with a cylinder immersion.
Appendix D - Smart Immersion Relay
D.3 SMART IMMERSION FUNCTIONALITY
D.3.1 LEGIONELLA PROTECTION
Legionella protection can be scheduled on a weekly basis to
heat the DHW cylinder to 60°C. Legionella disinfection should be
scheduled in a window that is a minimum of 1 hour after a DHW
demand and in a setback heating demand period e.g. Overnight.
This is to avoid the least amount of loss in the heating circuits.
The Legionella protection can not be run twice in a week should
the schedule be changed within the settings.
See Section 7.4 for Legionella protection.
D.3.2 SUPPLEMENTARY HEATING
The Grant Aerona Smart controller can enable supplementary
heating using the immersion heater in an external volumiser or
Low Loss header.
The software enables the user to congure the time delay for the
immersion heater to switch on after a specic demand has begun.
Refer to Section 8 - Heaters for the settings of the time delay as
well as temperature activation set points.
! WARNING !
There will 2 mains supplies within the Immersion relay
enclosure. Ensure both are isolated before removing the
cover.
230 VAC
13 14 15 16 17 18 19 20 21 22
1 2
L N E
230V
50HZ
5A
N
Smart Immersion
Relay
Smart Immersion
Relay
Wiring Centre Terminals
Double
Minature
Circuit
Breaker
Pole
Isolator
13A
20A
L
Blue
Brown
Cylinder
Immersion
Heater
Brown
Blue
G/Y
N
G/Y
A1
1 2
A2
N
Double
Pole
Isolator
13A
L
Blue
Brown
External Volumiser/LLH
Immersion heater
Brown
Blue
G/Y
N
G/Y
A1
1 2
A2
Some Earth connections have been
excluded for clarity. Grant Smart Immersion
relay to house 2 live connections. Ensure
both are isolated prior to opening housing.
Earth wires to be
linked inside
Immersion relay
enclosure(s).
Figure D-1: Immersion relay examples