4.3 Water Pipe Work
Note: Prevent the field piping from straining the piping on the hydrobox by
fixing it to a wall or applying other methods.
Hot Water Pipework
The function of the following safety components of the hydrobox should be
checked on installation for any abnormalities;
• Pressure relief valve
• Expansion vessel pre-charge (gas charge pressure)
The instruction on the following pages regarding safe discharge of hot water from
Safety devices should be followed carefully.
• The pipework will become very hot, so should be insulated to prevent burns.
• When connecting pipework, ensure that no foreign objects such as debris or the
like enter the pipe.
Safety Device Connections
The hydrobox contains a pressure relief valve. (see <Figure 4.3.1>) The connec-
tion size is G1/2" female. The installer MUST responsibly connect appropriate
discharge pipework from this valve in accordance with local and national regula-
Failure to do so will result in discharge from the pressure relief valve directly into
the hydrobox and cause serious damage to the product.
All pipework used should be capable of withstanding discharge of hot water.
Relief valves should NOT be used for any other purpose, and their discharges
should terminate in a safe and appropriate manner in accordance with local regu-
Note: Beware that the manometer and the pressure relief valve are NOT
strained on its capillary side and on its inlet side respectively.
If a pressure relief valve is added, it is essential that no check valve
or isolation valve is fitted between the hydrobox connection and the
added pressure relief valve (safety matter).
Hydraulic Filter Work (ONLY EHPX series)
Install a hydraulic filter or strainer (local supply) at the water intake ("Pipe E" in
Table 3.4, also see associated schematic Fig. 3.5)
Connections to the hydrobox should be made using the 28mm compression
(EHSC/D series) or the G1 nut (ERSC/D series) the G1-1/2 nut (E*SE series) as
appropriate. (The hydrobox has G1 or G1-1/2 (male) thread connections.)
Do not over-tighten compression fittings as this will lead to deformation of the olive
ring and potential leaks.
Note: Before brazing pipes in the field, protect pipes on the hydrobox using
wet towels etc as "heat shield".
Use two wrenches to tighten piping connection (see <Figure 4.3.2>).
Drain Pipework (ONLY ER series)
The drain pipe should be installed to drain condensing water in Cooling mode.
• Securely install the drain pipe to prevent leakage from the connection.
• Securely insulate the drain pipe to prevent water dripping from the locally supplied
• 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
1. Apply polyvinyl chloride type adhesive over the shaded surfaces inside of the
drain pipe and on the exterior of the drain socket as shown.
2. Insert the drain socket deeply into the drain pipe <Figure 4.3.3>.
Note: Securely support the locally supplied drain pipe using pipe support to
avoid the drain pipe falling from the drain socket.
To prevent dirty water from draining directly onto the floor next to hydrobox,
please connect appropriate discharge pipework from the hydrobox.
Insulation of Pipework
• All exposed water pipework should be insulated to prevent unnecessary heat loss
and condensation. To prevent condensate entering the hydrobox, the pipework
and connections at the top of the hydrobox should be carefully insulated.
• Cold and hot water pipework should not be run close together where possible, to
avoid unwanted heat transfer.
• Pipework between outdoor heat pump unit and hydrobox should be insulated with
suitable pipe insulation material with a thermal conductivity of ≤ 0.04 W/m.K.
< Figure 4.3.10 >
Discharge to drain
(pipe MUST responsibly be fitted by installer).
Apply polyvinyl chloride
Factory-fitted pressure relief valve
(G1/2" female connection)