37
Water control
SMGB0066 rev.0 - 12/2009
Water pipe
installation
Service Manual
2
note
The factory default ON/OFF temperature differential is “4 °C”. Note that the minimum water volume varies for
-
different setting for each purpose as shown in the table above.
Minimum required water volume during defrosting
2.
The following table shows the minimum water volume needed in each YUTAKI unit in case of a permitted drop in
temperature of 10ºC.
Model
Water
temperature drop
rHUE-3AVHn
rHUE-4AVHn
rHUE-5A(V)Hn rHUE-6A(V)Hn
5ºC
212
276
342
410
10ºC
106
138
171
205
15ºC
71
92
114
137
20ºC
53
69
86
103
25ºC
42
55
68
82
(Units are in ltrs.)
note
The values shown on the table are based on theoretical installation conditions, and therefore, it rests with the
-
client to recalculate these values depending on the real conditions of the installation.
2.2.2. Correction factor due to use of glycol
When the ambient temperature is low in winter, it is possible that the unit will be damaged by freezing water in the pipes and
in the circulating pump during the shutdown periods.
In order to prevent this, it is useful to empty the water from the installation or to maintain the supply to the installation, as an
electric cord can prevent the water from freezing in the circuit.
Additionally, in cases where water drainage is difficult, an antifreeze mixture of ethylene glycol or propylene should be used
(Between 10 % and 40 %).
The performance of the unit when working with glycol may decrease in proportion to the percentage of glycol used, as the
density of glycol is higher than that of water. (For more information, see TCGB0066)
2.3. WATEr ConTrol
caution
Malfunction. Damage by poor quality water. Industrial water rarely causes deposits of scales or other foreign
-
substances on equipment and the most vulnerable components are plate heat exchangers. However, well water
or river water may in most cases contain suspended solid matter, organic matter, and scales in great quantities.
Therefore, such water should be subjected to filtration or softening treatment with chemicals before its use as
heat transporter in Yutaki unit.
