Daikin EWAQ005ACV3P Installation Manual Download

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Installation manual

EWAQ+EWYQ005~007ACV3P

Packaged air-cooled water chillers and

packaged reversible air to water heat pumps

4PW33165-1D

■

Drain taps must be provided at all low points of the system to
permit complete drainage of the circuit. Two drain valves are
provided inside the unit.

■

Air vents must be provided at all high points of the system. The
vents should be located at points which are easily accessible for
servicing. An automatic air purge is provided inside the unit.
Check that this air purge valve is not tightened too much so that
automatic release of air in the water circuit remains possible.

■

Take care that the components installed in the field piping can
withstand the water pressure.

Checking the water volume and expansion
vessel pre-pressure

The unit is equipped with an expansion vessel of 6 litre which has a
default pre-pressure of 1 bar.

To assure proper operation of the unit, the pre-pressure of the
expansion vessel might need to be adjusted and the minimum and
maximum water volume must be checked.

Check that the total water volume in the installation is 10 l
minimum:

Using the table below, determine if the expansion vessel pre-
pressure requires adjustment.

Using the table and instructions below, determine if the total
water volume in the installation is below the maximum allowed
water volume.

Calculating the pre-pressure of the expansion vessel

The pre-pressure (Pg) to be set depends on the maximum
installation height difference (H) and is calculated as below:

Pg=(H/10+0.3) bar

Checking the maximum allowed water volume

To determine the maximum allowed water volume in the entire circuit,
proceed as follows:

Determine for the calculated pre-pressure (Pg) the
corresponding maximum water volume using the graph below.

Check that the total water volume in the entire water circuit is
lower than this value.

If this is not the case, the expansion vessel inside the unit is too small
for the installation.

Example 1

A heat pump model unit is installed 5 m below the highest point in the
water circuit. The total water volume in the water circuit is 100 l

In this example, no action or adjustment is required.

Example 2

A heat pump model unit is installed 4 m below the highest point in the
water circuit. The total water volume in the water circuit is 190 l.

Result:

■

Since 190 l is higher than 170 l, the pre-pressure must be
decreased (see table above).

■

The required pre-pressure is:
Pg = (H/10 + 0.3) bar = (4/10 + 0.3) bar = 0.7 bar

■

The corresponding maximum water volume can be read from
the graph: approximately 200 l.

■

Since the total water volume (190 l) is below the maximum water
volume (200 l), the expansion vessel suffices for the installation.

Setting the pre-pressure of the expansion
vessel

When it is required to change the default pre-pressure of the
expansion vessel (1 bar), keep in mind the following guidelines:

■

Use only dry nitrogen to set the expansion vessel pre-pressure.

■

Inappropriate setting of the expansion vessel pre-pressure will
lead to malfunction of the system. Therefore, the pre-pressure
should only be adjusted by a licensed installer.

NOTE

In most air conditioning applications this minimum
water volume will have a satisfying result.

In critical processes or in rooms with a high heat
load though, extra water volume might be
required.

Installation

height

difference

(a)

(a) Installation height difference: height difference (m) between the highest point of

the water circuit and the unit. If the unit is located at the highest point of the
installation, the installation height is considered 0 m.

Water volume

≤

300 l (EWAQ)