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TERMINAL
LABEL
NUMBER
1-2
DO NOT USE
3-4
TANK SENSOR
5-6
DO NOT USE
7-8
GENERAL BLOCKING
9-10
EMPTY
EXTERNAL FLOW
11-12
WATER PRESSURE
SWITCH
ON/OFF STAT,
OPEN THERM
HEATING CIRCUIT
13-14
15-16
0 – 10 VDC
CASCADE
17-18
CONNECTION
LOCK OUT
19-20
TOP
BURNER RUNNING
21-22
TOP
BURNER DEMAND
23-24
TOP
LOCK OUT
25-26
BOTTOM
BURNER RUNNING
27-28
BOTTOM
BURNER DEMAND
29-30
BOTTOM
BURNER DEMAND
29-30
BOTTOM
34-35-36
DO NOT USE
37-38-39-40
DO NOT USE
POWER SUPPLY
41-42-43
230VAC
15.3.4
WIRING TERMINALS
DESCRIPTION
Do not connect any cables to these connections
Connect the tank sensor to this connection. This external flow sensor measures the flow temperature at the
system side. The sensor must be mounted on the supply pipe at the system side, close to the tank. NOTICE:
The sensor must be used when several water heaters are cascaded with the internal cascade manager.
Do not connect any cables to these connections
This connection is used for the flow switch, a standard part for the TTW
N/A
A water pressure sensor is mounted in the water heater.
This connection has the following options:
If 24 hour operation is required, a link wire should be fitted to terminals 13-14. The water heater will use
the set/programmed flow temperature for the heating circuit when these terminals are linked.
If an on/off thermostat and/or time programmer is to be used, they should be linked in series to these
terminals. When there is a closed circuit, the water heater will use the set/programmed flow
temperature for the heating circuit.
An OpenTherm communication bus can be used to connect to an advanced time and temperature controller
such as the Lochinvar RC Controller or EBC Controller. The controller will then communicate with the water
heater and determine the optimum flow temperature to achieve the desired room temperature. When an
external temperature sensor is connected, the water heater communicates the recorded temperature to the
controller and the compensation curve is adjusted automatically.
The water heater can be driven by an external control through a 0 to 10 VDC control signal. A voltage of less
than 1.4V gives no heat demand, 1.48 V gives minimum set point and 10V gives maximum set point.
NOTE: This connection is polarity sensitive therefore the 0 – 10V line must be connected to terminal 15 and
the 0V line to terminal 16. A link wire must not be connected to terminals 57 & 58 when 0 – 10V control is
used.
The Lochinvar TTW water heater has a built in cascade management system. When two or more water heaters
are connected in a cascade, each water heater of the cascade has to be connected to the next water heater
using terminals 61 & 62. This connection is polarity sensitive (all terminals 61's to be linked and all terminal 62's
to be linked) and should be made using screened cable.
One water heater has to be appointed as a Master, while the other water heater(s) are the Slaves. All external
controls such as Calorifier sensor, external temperature sensor, system pumps etc. are to be connected to the
Master water heater.
For a cascade to work correctly, it is essential that an external flow temperature sensor is used.
In order for the cascade to work correctly, each connected water heater needs to be programmed with a
different address using a computer interface. For further details, please contact Lochinvar Limited.
This contact is N.O. (normally open max. 230 Vac, 0.8 A). When the unit is in lock-out this contact will close. This
contact can also be used for the switching of a pump with a separate control input connection.
This contact is N.O. (normally open max. 230 Vac 0,8 A). When the unit starts the burner and detects the flame,
this contact will be closed. This contact can also be used to control an external (extra) water heater. This contact
can also be used for the switching of a pump with a separate control input connection.
This contact is N.O. (normally open max. 230 Vac 0,8 A). When the unit receives any heat demand this contact
will close. This contact can also be used for the switching of a pump with a separate control input connection.
This contact is N.O. (normally open max. 230 Vac, 0.8 A). When the unit is in lock-out this contact will close.
This contact is N.O. (normally open max. 230 Vac 0,8 A). When the unit starts the burner and detects the flame,
this contact will be closed. This contact can also be used to control an external (extra) water heater.
This contact is N.O. (normally open max. 230 Vac 0,8 A). When the unit receives any heat demand this contact
will close.
This contact is N.O. (normally open max. 230 Vac 0,8 A). When the unit receives any heat demand this contact
will close.
Do not connect any cables to these connections
Do not connect any cables to these connections
This connection is pre-wired and should not be altered. Where a 3-phase supply is used, the water heater
must have a 16 A fuse per phase. See Section 11.2.3: MAINS SUPPLY CONNECTION – THREE PHASE SUPPLY
or Section 11.2.4: MAINS SUPPLY CONNECTION – SINGLE PHASE SUPPLY for details on the incoming supply
connection.
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