Installation Procedure For Dhw Tank - Mitsubishi Electric EHSC serie Para El Instalador

5
System Set Up

5.4 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.
. 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 on the
page 9, Figure 3.7 or 3.8 as applicable.
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-TH0TK-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.
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. 9- (OUT4).
The TBO. 9- terminals on the FTC4 are shown in the wiring diagram on
Page 22.
Choose the terminals that the 3-way valve is connected to between TBO.
9-0, or TBO. 9-, according to the rated voltage.
When the rated current of the 3-way valve exceeds 0.A, be sure to use
a relay with maximum voltage and current ratings of 230V AC / 0.A when
connecting to the FTC4. Do not directly connect the 3-way valve cable to the
FTC4. Connect the relay cable to the TBO. 9-0 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 fol-
lowing;
Specification of 2-way valve (field supply)
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.
(5) It is essential that no check valve or isolating valve is fitted between the hydrobox and the pressure relief valve.
• Power supply: 230V AC
• Current: 0.A Max (If over 0.1A you must use a relay)
• Type: Normally closed
Installation
position
2-way valve DHW
2-way valve2 Heating
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 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 SW-3 on the FTC4 to ON.
6. When using an immersion heater (field supply), connect a contact relay cable
for the immersion heater to TBO.2 9-0 (OUT9), and turn the Dip SW-4 to
ON. Do NOT directly connect the power cable to the FTC4.
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.
Connector CNW5
Electrical connection Output signal
terminal block
Heating DHW
TBO. 9-0 OFF ON
(closed) (open)
TBO.2 7-8 ON OFF
(open) (closed)
Dip-SW1
System
OFF
OFF
(closed)
OFF
(closed)
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