Midea MSH-07CRN1, MSH-07HRN1, MSH-09CRN1, MSH-09HRN1, MSH-12CRN1, MSH-12HRN1 Manual page 270

The service rules of the R407C product
The service rules of the R410A product
1. The service rules of the new refrigerant R407C product
Midea uses the green refrigerant R407C firstly in China.
Its thermal characters are similar to R22, but there is little difference between them.
1.1 The main difference between R407C and R22:
Component
The ratio of mix Wt
The saturation liquid density Kg/m
Specific heat Normal pressure kj/kg.k
The saturation liquid kj/kg.k 1.554
Evaporating pressure
Condensing pressure
Temperature slippage
Heating capacity
Input power
COP
The consistent with the oil
1.2 Service precautions:
1.2.1 Because R407C is a mixture composed of three kinds of matter, when vapor phase and liquid
phase coexist, the component of the vapor phase is different from the liquid phase. When we fill
the refrigerant, we must ensure to fill it in liquid phase, in order to maintain the stability of the
character.
1.2.2 The leakage of the refrigerant is from vapor side or liquid side, and the leakage from vapor side
could make the component change and impact the character seriously. So when the amount of
the leakage is up to 5%, we need discharge all refrigerant in the system, and fill liquid
refrigerant according to amount in nameplate.
1.2.3 Because the lubricant fit for refrigerant R407C is ester refrigerating engine oil (POE) or ether
refrigerating engine oil (PVE). The mineral lubricant fit for refrigerant CFC and HCFC is weak in
consistent with the HFC, and it doesn't fit for the refrigerant HFC. So when the compressor
using new refrigerant R407C is worn out, to replace it by compressor of CFC or HCFC is
forbidden.
1.2.4 When the connection of the refrigerant pipe is finished, before the system start up we should
vacuum the indoor unit by cut-off valve or discharge the indoor unit air by refrigerant R407C
bottle. Discharged the air in system by outdoor unit refrigerant is forbidden.
1.2.5 Ester oil could adsorb the water in the air. In order to removemoisture in refrigeration system,
avoid capillary jammed by ice and the ester lubricant oil decomposed with water, we use
desiccant in system. Artificial zeolite (molecular sieve R etc.) is the effective water sorbent.
Toavoid absorb refrigerant but only absorbmoisture, we use the molecular sieve whose
aperture is smaller than the molecule of the refrigerant. For R407C we should adopt XH-11
rather than XH-9AK and 4A-NRG.
1.2.6 Because the corrosion of R407C and POE to high molecular material is different from R22 and
mineral oil, the airproof material inside high/low pressure valve and foul-way valve needs to be
changed in refrigeration system, such as R407C, polyurethane rubber etc. The high/low
pressure valve and four-way valve which are fit for R22 couldn't be used in service.
1.2.7 When there is leakage, filling with other kind of refrigerant is forbidden.
1.2.8 When we need to vacuum the system, we should use the special quick joint, but use the quick
joint of other refrigerant is forbidden lest pollute by mixing refrigerant. The time for vacuuming is
3
kpa
kpa
w
w
R407C R22
HFC32/125/134a HCFC22
23/25/52 100
1136 1191
0.835 0.622
1.256
499 498
2112 1943
4.3-7.1 0
92-97 100
106 100
97 100
Fat oil Mineral oil
5