Hitachi YUTAKI M R32 Series - Insulation; Water Filling

56
PMML0600 rev.0 - 06/2022
5
SPACE HEATING AND DHW FOR YUTAKI M / YUTAKI HYDROSPLIT
DRAIN AND WATER PIPING
! CAUTION
• Do not add glycol that has been exposed to air as glycol absorbs water to the environment. Final
glycol concentration can be lower than expected, allowing system to freeze up.
• Corrosion, that can damage gravely the system, is possible when glycol is added. Uninhibited
glycol with oxygen can become acidic & attack metal surfaces, forming galvanic corrosion
cells. The responsible installer must be a qualied water specialist & should decide which anti-
freeze solution is necessary for each site’s conditions. Corrosion inhibitors must be selected
to counteract acids formed by glycol oxidation. Inhibitors with limited lifetime or containing
silicates are forbidden. Galvanized pipes must be avoided since they can precipitate inhibitors.
When using inhibitors, always follow manufacturer’s instructions and ensure that the product is
appropriate for materials used in water circuit.
• Adding glycol to water circuit reduces the maximum allowed water volume of the system and
also capacity. Additional info can be found on Technical Catalogue.
5.5.7 Insulation
Water circuit piping must be insulated to prevent condensation and to reduce heat loss.
For outdoor water piping, recommended insulation thickness depends on piping length.
Recommended thickness values for an insulation of ʎ=0.039W/mK are shown in table below.
Piping length (mm) Minimum insulation thickness (mm)
<20 19
20 - 30 32
30 - 40 40
40-50 50
5.5.8 Water lling
1 Check that a water check valve (ATW-WCV-01 accessory) with a shut-o valve (eld supplied)
is connected to the water lling point (water inlet connection) for lling the space heating
hydraulic circuit (see “5.2 Outdoor Unit Draining Operation”).
2 Make sure all the valves are open (water inlet/outlet shut-o valves and the rest of valves of
the space heating installation components).
3 Ensure that the air purgers of the unit and installation work correctly.
4 Connect a drain pipe to the safety valve and make sure that it is correctly connected to the
general draining system. The safety valve is later used as an air purging device during the
water lling procedure.
5 Fill the space heating circuit with water until the pressure displayed on the manometer
reaches approximately 1.8 bar.
 NOTE
While the system is being lled with water, it is highly recommended to operate the safety valve