Mitsubishi Electric PAC-IF051B-E Installation Manual page 24

4. Electrical work
4. Installation procedure for DHW tank
Note:
• Be aware that the respective DHW operations are greatly effected by the
selections of the components such as tank, immersion heater, or the like.
• Follow your local regulations to perform system configuration.
1. To enable switching of the water circulation circuit between the DHW mode and
the heating mode, install a 3-way valve (field supply). The 3-way valve and the
DHW tank should be positioned as shown in the system diagram in section 3.
The use of two 2-way valves can perform the same function as a 3-way valve.
2. Install the optional thermistor THW5 (optional part PAC-TH011TK-E) on the
DHW tank.
It is recommended to position the thermistor at the mid point of the DHW tank
capacity. Insulate thermistor from ambient air. Especially for double (insulated)
tank, thermistor should be attached to the inner side (to detect the water tem-
perature).
3. Connect the thermistor lead to the CNW5 connector on the FTC4 (Master).
If the thermistor lead is too long bundle it with a strap to adjust the length.
4. The output terminals for the 3-way valve is TBO.1 9-11 (OUT4).
The TBO.1 9-11 terminals on the FTC4 (Master) are shown in the wiring diagram
on the page 20.
Choose the terminals that the 3-way valve is connected to between TBO.1 9-10,
or TBO.1 9-11, according to the rated voltage.
When the rated current of the 3-way valve exceeds 0.1A, be sure to use a relay
with maximum voltage and current ratings of 230V AC / 0.1A when connecting
to the FTC4 (Master). Do not directly connect the 3-way valve cable to the FTC4
(Master). Connect the relay cable to the TBO.1 9-10 terminals.
3-way valve must be of SPST type. SPDT type can NOT be used.
For systems using 2-way valves instead of a 3-way valve please read the follow-
ing;
TBO.1 9-11
TBO.2 7-8
TBO.2 9-10
WARNING: When connecting DHW tank
(1) Attach the optional thermistor THW5 (PAC-TH011TK-E).
(2) Always use earth leakage breaker when connecting immersion heater.
(3) When installing an immersion heater, be sure that the immersion heater has a built-in direct cut-off thermostat.
(4) Connect a pressure relief valve on the sanitary water side.
24
Specification of 2-way valve (field supply)
• Power supply: 230V AC
• Current: 0.1A Max (If over 0.1A you must use a relay)
• Type: Normally closed
Installation Electrical connection
position terminal block
2-way valve1 DHW TBO.1 9-10
2-way valve2 Heating TBO.2 7-8
Note: Should the 2-way valve become blocked the water circulation will stop.
A by-pass valve or circuit should be installed between pump and 2-way valve
for safety.
The TBO.2 7-8 terminals on the FTC4 (Master) are shown in the wiring diagram.
The 2-way valve (field supply) should be installed according to the instruc-
tions supplied with it. Follow 2-way valve's manufacturer's instructions as to
whether to connect an earth cable or not.
• For the 2-way valve, choose the one that slowly opens and shuts off to
prevent water hammer sound.
• Choose the 2-way valve equipped with manual override, which is neces-
sary for topping up or draining of water.
5. Turn the DIP SW1-3 on the FTC4 (Master) to ON.
6. When using an immersion heater (field supply), connect a contact relay cable for
the immersion heater to TBO.2 9-10 (OUT9), and turn the Dip SW1-4 to ON. Do
NOT directly connect the power cable to the FTC4 (Master).
Note:
• When an immersion heater is installed, select appropriate breaker capacity and
a cable with appropriate diameter on the basis of heater output.
• When wiring an immersion heater in the field, always install an earth leakage
breaker to prevent accidental electric shock.
Output signal
Heating DHW System
OFF
OFF ON OFF
(closed) (open) (closed)
ON OFF OFF
(open) (closed) (closed)
Dip SW1