Sizing Expansion Vessels - Mitsubishi Electric EHPT Serie Manual De Instalación

4
Installation
Drain Pipework (ONLY ER series)
The optional part 'Drain pan stand' does not need to be set because the drain pan
is installed.The drain should be set from the drain socket at left rear of the unit.
The drain pipe should be installed to drain condensed water during cooling mode.
• To prevent dirty water from draining directly onto the floor next to cylinder unit,
please connect appropriate discharge pipework from the cylinder drain pan.
• Securely install the drain pipe to prevent leakage from the connection.
• Securely insulate the drain pipe to prevent water dripping from the locally
supplied drain pipe.
• Install the drain pipe at a down slope of 1/100 or more.
• Do not place the drain pipe in drain channel where sulphuric gas exists.
• After installation, check that the drain pipe drains water properly from the outlet of
the pipe to suitable discharge location.
Drain hose

Sizing Expansion Vessels

Expansion vessel volume must fit the local system water volume.
To size an expansion vessel for the heating circuit the following formula and
graph can be used.
When the necessary expansion vessel volume exceeds the volume of an built-in
expansion vessel, install an additional expansion vessel so that the sum of the
volumes of the expansion vessels exceeds the necessary expansion vessel
volume.
* For installation of an E**T***-*M*ED* model, provide and install a suitable
primary-side expansion vessel and additional 3 bar rated pressure relief valve in
the field as the model DOES NOT come fitted with a primary-side expansion
vessel.
Where;
ε × G
V : Necessary expansion vessel volume [L]
V =
P ¹ + 0.098
ε
1 −
P ² + 0.098 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
P ¹ : 0.1 MPa
P ² : 0.3 MPa
*A 30% safety margin has been added.
Drain socket
: Water expansion coefficient
: at 70°C = 0.0229
<Installation>
1. The drain socket (inside diameter 26mm) is left rear of the cylinder unit. (Figure
4.3.1)
2. Fix the drain pipe (VP-20) which fits the drain socket with the polyvinyl chloride
type adhesive.
3. Set the drain pipework up to the outlet with the down grade of more than one
hundredth.
Note: Securely support the locally supplied drain pipe to avoid the drain pipe falling
from the drain socket.
<Figure 4.3.1>
Expansion vessel sizing
25
20
15
10
5
0
0 50 100 150 200 250 300
System water volume [L]
<Figure 4.3.2>
en
350 400
12