Pressure Testing; Evacuating; Electrical & Fuses - Marstair A2LSYSTEMATCH SMC 15 Technical Manual

2E PRESSURE TESTING
The pressure testing section of the risk assessment template or equivalent should be carried out before commencing

pressure testing.

Pressure and leak testing of the system should be completed in accordance with EN 378.
Note: The interconnecting pipework and evaporator are all on the low-pressure side of the system. The only high-
pressure side of the system is within the condensing unit. Therefore, the pressure and leak testing of the pipework can
be treated as such within EN 378.
The matched MBMT evaporators all have a maximum allowable pressure of 25Barg
The condensing unit is fitted with a high-pressure limiting device
SMC15-40 = 23Bar
SMC45-100 = 26Bar
The condensing unit has a pressure relief valve is set to 29.5Bar which is equal to the condensing unit maximum
allowable pressure do not exceed this pressure if testing the condensing unit.
2F EVACUATING
The Evacuation section of the risk assessment template or equivalent should be carried out before commencing
Evacuation.
With the valves open, connect a vacuum pump to the service ports on the outdoor unit valves. Evacuate the
interconnecting pipework and indoor unit to 1000 microns (1 Torr) or better. Allow this to be held for a minimum of 15
minutes.
2G ELECTRICAL & FUSES
The installer supplies mains, control and interconnecting cables: equipment must be earthed.
Wiring must be carried out in accordance with local and national codes.
Mains supply cables must be size compatible with the recommended fuse.
Cable clamps for use with stranded cables are supplied in units 15 - 100 and should be used to secure incoming/outgoing
cables. Installers must supply a method of securing solid sheathed cables.
THREE PHASE UNITS WITH SCROLL COMPRESSORS:
On 3 Ph units sizes it is possible for the scroll compressor to run backwards.
This becomes obvious on start up - the compressor will not develop a normal running pressure differential and the top will
not become warm: it may be excessively noisy. If this happens, switch off the mains power and exchange the two supply
phases not connected to the indoor unit. This will correct the rotation.
FUSES: The system and its supply/interconnecting wiring must be protected by fuses, preferably High Rupture Current
(HRC) motor rated types (to BS EN60269) or miniature circuit breakers to (BS EN60898) or local codes having similar
time lag characteristics, that allow starting of the compressor yet still afford close overcurrent protection under running
conditions. The ratings below are for HRC motor rated fuses.
1PH Fuse
SMC 15
Fuse 16
3PH Fuse
SMC 40
Fuse 10
The ratings are for the outdoor unit only. Currents for the indoor units including heaters if applicable should be noted and
the fuse size increased pro-rata if using same supply.
20 30 40
16 16 20
45 50 80
10 10 10
90
16
10
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