Daikin SERHQ020BAW1, Installation And Operation Manual

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4 Preparation
Installation and operation manual
10
SERHQ020~0 SEHVX20~64BAW
Split packaged air-cooled water chiller
4P508019-2B – 2018.01
Outdoor unit ▪ Piping connection sizes
Indoor unit Gas Liquid Outdoor unit Gas Liquid
SEHVX20BAW Ø25.4 mm Ø12.7 mm 1× SERHQ020BAW1 Ø22.2 mm Ø9.52 mm
SEHVX32BAW Ø25.4 mm Ø12.7 mm 1× SERHQ032BAW1 Ø28.6 mm Ø12.7 mm
SEHVX40BAW Ø25.4 mm Ø12.7 mm 2× SERHQ020BAW1 Ø22.2 mm Ø9.52 mm
SEHVX64BAW Ø25.4 mm Ø12.7 mm 2× SERHQ032BAW1 Ø28.6 mm Ø12.7 mm
▪ Field piping sizes
Indoor unit G/G1 L/L1 G2 L2
SEHVX20BAW Ø28.6 mm Ø9.52 mm — —
SEHVX32BAW Ø28.6 mm Ø12.7 mm — —
SEHVX40BAW Ø28.6 mm Ø9.52 mm Ø28.6 mm Ø9.52 mm
SEHVX64BAW Ø28.6 mm Ø12.7 mm Ø28.6 mm Ø12.7 mm
If the indoor unit connections do not match the diameter of the
specified piping requirements, the piping diameter requirements
must be met using reducers/expanders (field supply) on the indoor
unit connections.
Other diameters (mm sizes) can also be used if the required pipe
sizes (inch sizes) are not available, taking the following into account:
▪ select the pipe size nearest to the required size,
▪ use the suitable adapters for the change-over from inch to mm
pipes (field supply).
4.2.3 About the piping length
Maximum piping length and height difference
Maximum allowable piping length 30 m
Height difference between indoor and outdoor unit <10 m
Height difference between outdoor unit 1 and outdoor
unit 2 (if applicable) 0 m
4.3 Preparing water piping
4.3.1 To check the water volume and expansion
vessel pre-pressure
The unit has an expansion vessel of 12 litre with a default pre-
pressure of 1 bar.
To make sure that the unit operates properly:
▪ You must check the minimum and maximum water volume.
▪ You might need to adjust the pre-pressure of the expansion
vessel.
Minimum water volume
Model Minimum total water volume (l)
20 76
32 110
40 152
64 220
INFORMATION
In critical processes, or in rooms with a high heat load,
extra water might be required.
INFORMATION
The temperature step difference can be modified using
settings [A‑02] and [F‑00]. This has an impact on the
minimum water volume required when the unit operates in
cooling.
By default, the unit is set to have a water temperature
difference of 3.5 K which allows it to operate with the
minimum volume mentioned in the previous table.
However, if a smaller temperature differential is set, as in
the case of process cooling applications where
temperature fluctuations must be avoided, a larger
minimum water volume will be required.
To ensure proper operation of the unit when changing the
values of setting [F‑00] (for cooling mode), the minimum
water volume has to be corrected. If this volume exceeds
the range allowed in the unit, an additional expansion
vessel or a buffer tank must be installed in the field piping.
Example:
To illustrate the impact on the system when modifying the setting
[F‑00], we will consider a unit with a minimum allowable water
volume of 66 l. The unit is installed 5 m below the highest point in
the water circuit.
Assuming that the setting [F‑00] is changed from 5°C (default value)
to 0°C. From the below table we see that 5°C corresponds to a
temperature differential of 3.5 K and 0°C to 1 K, which is actually the
lowest value we can set.
[F‑00] value (°C) Temperature differential (K)
0 1
1 1.5
2 2
3 2.5
4 3
5 3.5
6 4
7 4.5
8 5
9 5.5
10 6
11 6.5
12 7
13 7.5
14 8
15 8.5
The water volume correction factor according to the curve shown in
the below graph is 3.5; this means that the minimum volume will be
3.5 times larger.
Correction factor curve for minimum water volume