Sizing Expansion Vessels; Water Circulation Pump Characteristics - Mitsubishi Electric ecodan ERSE series Installationshandbuch

4
Installation

Sizing Expansion Vessels

Expansion vessel volume must fit the local system water volume.
To size an expansion vessel both for the heating and cooling circuits the following
formula and graph can be used.
ε × G
V =
P ¹ + 0.098
1 −
P ² + 0.098
Where;
V : Necessary expansion vessel volume [L]
ε : Water expansion coefficient
G : Total volume of water in the system [L]
P ¹ : Expansion vessel setting pressure [MPa]
P ² : Max. pressure during operation [MPa]
Graph to the right is for the following values
ε : at 70 °C = 0.0229
P ¹ : 0.1 MPa
P ² : 0.3 MPa
* 30% safety margin has been added.

Water Circulation Pump Characteristics

Pump speed can be selected by main remote controller setting (see <Figure
4.3.6>).
Adjust the pump speed setting so that the flow rate in the primary circuit is appro-
priate for the outdoor unit installed (see Table 4.3.1). It may be necessary to add
an additional pump to the system depending on the length and lift of the primary
circuit.
<Second pump>
If a second pump is required for the installation please read the following care-
fully.
If a second pump is used in the system it can be positioned in 2 ways.
The position of the pump influences which terminal of the FTC the signal cable
should be wired to. If the additional pump(s) have current greater than 1A please
use appropriate relay. Pump signal cable can either be wired to TBO.1 1-2 or
CNP1 but not both.
Option 1 (Space heating/cooling only)
If the second pump is being used for the heating circuit only then the signal cable
should be wired to TBO.1 terminals 3 and 4 (OUT2). In this position the pump can
be run at a different speed to the hydrobox's in-built pump.
Option 2 (Primary circuit DHW and space heating/cooling)
If the second pump is being used in the primary circuit between the hydrobox and
the outdoor unit (Package system ONLY) then the signal cable should be wired to
TBO.1 terminals 1 and 2 (OUT1). In this position the pump speed MUST match
the speed of the hydrobox's in-built pump.
Note: Refer to 5.2 Connecting inputs/outputs.
Expansion vessel sizing
25
20
15
10
5
0
0 50 100 150
System water volume [L]
<Figure 4.3.5>
Outdoor heat pump unit Water flow rate range [L/min]
PUHZ-SW160
PUHZ-SW200
PUHZ-SHW230
<Table 4.3.1>
* If the water flow rate exceeds 61.5 L/min, the flow speed will be greater than 1.5 m/s,
which could erode the pipes.
EHSE/ERSE series
140
120
100
80
60
40
20
0
0 10 20 30
<Figure 4.3.6>
200 250 300 350
23.0 - 61.5
28.7 - 61.5
28.7 - 61.5
Speed 5 (Default setting)
Speed 4
Speed 3
Speed 2
Speed 1
40 50 60 70 80
Flow rate [L/min]
400
90
14