Duct Connections; Medium Connections / Heating Coil; Condensate Drainage - Ruck RLI 700 FC Assembly And Operating Manual

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Fig. 5:
Connection air duct
- -
Bypass circuit
+
Admixture circuit
+
Injection circuit
Fig. 6:
Standing water height H
Δ p [Pa] H [mm]
st
300 60
400 60
500 66
600 76
700 86
800 97
Table 1:
Standing water height H in siphon
as a function off pressure.

6.1. Duct connections

During installation the standard diffusor / noise diffusor the following points should be noted and followed:
• For the duct diameter transition, accessories are used.
• Fasten transition piece to the housing (Rotoline) with 4 hexagon-head bolts (M8x20).

6.2. Medium connections / Heating Coil

• Before connecting heating coil, the duct system must be thoroughly cleaned.
• Use only permitted sealants (DIN EN 751-2, DVGW tested).
• Water connections as marked on the heat exchanger.
• When making pipe connections to the unit, with screw connections, a wrench, for example, must
be used to hold against the tightening torque.
• The connection must be executed without tension.
• Air bleeding must be executed through a threaded sleeve on which a corresponding valve can
be connected, keeping the cooling and heating medium in mind.
• All pipes and fi ttings of the medium connections must be insulated.
Hydraulic circuits
For air conditioning applications, there are three basic circuits:
Bypass circuit
With the bypass circuit, only the hot water is fed to the heating coil. The rest of the water supplied
by the pump bypasses the heating coil. This can lead to a temperature difference between top and
bottom of the heating coil if the fl ow of water through it is very small. The resulting temperature
gradients can lead to false temperature measurements in the duct or to draught effects in the room.
The bypass circuit is usually used in air coolers. In air coolers, the air is partly cooled below the dew
point and thereby dehumidifi ed.
Admixture circuit
In the admixture circuit, the circulating pump always supplies the full amount of water required by
the heating coil with an amount of hot water determined by the valve setting. The temperature is
thus constant over the whole heating surface. The temperature control is thus much better. Further-
more, the risk of frost damage when the pump is running is reduced as the continuous circulation
and increased pressure reduce the freezing point of the water. The only advantage of the bypass
circuit over the admixture circuit arises when the pipe lengths between three-way ball valve and wa-
ter heater are very long. Because the pump is ahead of the valve, there is always hot water available
at the valve that can be immediately fed to the heat exchanger if required. When in admixture circuit
it is possible the water in the pipe to the valve cools, so when heat is required there is a short delay
before the hot water reaches the heating coil.
Injection circuit
The combination of these circuits is the injection circuit, which is generally recommended.

6.3. Condensate drainage

• The cooler is equipped with a stainless steel condensate sump.
• A drainage connection from the condensate sump is brought out of the unit.
• To avoid corrosion, the drain pipe from this connection should be in stainless steel, copper or plastic.
• A siphon must be installed on each condensate drainage connection.
• The standing water height in the siphon depends on the pressure inside the unit, the minimum
is 60 mm. For internal pressures above 400 Pa, see table 1.
The standing water height can also be determined by calculation, provided the minimum of 60 mm
is maintained:
Example calculation:
p p p
Δ = Δ - Δ
st t d
p
Δ = 500 Pa (see technical data)
st
1 mm water gauge equals 9,81 Pa
Standing water height H
H = Δp / 9,81 Pa/mm + 15 mm
st
H = 500 Pa / 9,81 Pa/mm +15 mm
H = 66 mm
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Legend
Δp = Static pressure [Pa]
st
Δp = Total pressure [Pa]
t
Δp = Dynamic pressure [Pa]
d
H = Standing water [mm]
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