The fan-coil unit standard GB/t 19232-2003 on December 1, 2003 onwards the Executive. Standards and JB/T 4283-91 has a lot of changes that have been abolished, in which the performance parameters of high hydrostatic pressure unit was detailed provisions. Especially for concealed made clear provision to the performance test conditions. With no filters and diffusers of outlet pressure under 12Pa for unit tests, and the original standards required to be zero under hydrostatic pressure test results to have a certain difference. This article by a different type of fan coil units respectively in exports zero static pressure air and 12Pa state value, measured and power than, giving improved references, also on high hydrostatic pressure in structure of unit type describes the issues that should be noticed.
National standard GB/t 19232-2003 fan-coil units, was enacted on July 1, 2003, implemented from December 1, 2003. National Center for quality supervision and inspection of air conditioning equipment for detection of fan coil units have started to use national standard test methods provided, on unit performance index ratings provided by standard for judging.
National standard and has discontinued JB/T 4283-91 of the fan coil units, compared to from a model specification definitions, terminology and technical parameters, installation, and so there are a number of new provisions. On concealed unit test requirements change some more, and the dark machine groups and relatively broad in application, this article focuses on the darker machine groups to explore some of the problems in testing.
1. the terms, definitions
1.1 standard export static pressure in fan-coil unit clearly separate the low static pressure and high hydrostatic pressure. High static pressure unit is the unit in static pressure of not less than 30Pa Tuyere unit. Low static pressure set clearly defined export static pressure when with no filters and diffusers 12Pa. export static pressure, when rated air flow after overcoming their resistance, static pressure in the Tuyere, Pa.
1.2 rating refers to the standard test conditions, unit should meet the basic values, namely product nameplate and product samples of note values. Past on unit of performance judgment is pursuant to standard provisions of name value, on nameplate value and samples value not do judgment, unit of nameplate value and samples value General are than name value good, even good many, this to design units and user in selection Shi only pursuant to samples value, will produced deviation; in GB/T 19,232 standard in the provisions Dang nameplate value or samples value better than standard provisions value Shi, by nameplate value for judgment, such on control products quality, avoid some enterprise exaggerated publicity, this is production enterprise in prepared samples and products nameplate Shi should caused attention.
2. the effect of test methods
2.1 by original standards in the past at detecting horizontal dark machine group, general export static pressure is the detection of zero-voltage State, with no outlet for detection of concealed unit and filter, so you should test under static pressure 12Pa for export. GB increase in static pressure required for export of relevant parameters of the unit is in line with market demand.
2.2 for unit testing with static pressure requirements, in the detection of high, medium, low when the third parameter, first determine the static pressure value in the unit’s third export, recommends that the following two methods may be used:
(1) by high, medium and low wind in third gear ratio or air flow calculation
P=（L/ L） P ， P=（L/ L） P
P=LP ， P=LP
In the formula: p, p, P–high, medium and low export static pressure in third gear, Pa;
L, l, L–high, medium and low wind in third gear, unit m/h;
L, L–, medium proportional.
For example, when the high, medium and low wind in third gear according to the standards the recommended proportions when 1:0.75:0.5, unit export static pressure 12Pa respectively, 6.75Pa, 3Pa; third gear ratio when 1:0.8:0.6, unit export static pressure 12Pa, 7.68Pa, 4.32Pa, respectively.
(2) by noise test method for high, medium, low wind in third gear when exporting static pressure value.
3. horizontal concealed unit export in accordance with standard static pressure impact
We on different production enterprise two species model disc tube for detection, will horizontal dark mounted unit by export static pressure 0Pa and GB provisions of 12Pa Shi inspection results for comparison, unit of air in export static pressure 12 Pa than 0Pa reduce 6%~11% around, and power reduce 2%~4%, see table <1>, and table <2>, this description why unit installation in engineering Hou appears air enough of causes one, very worth production enterprise caused attention.
Table 1 x Unit comparison data
Export static 1 2 3 4 5 6 7
（m/n） 0 Pa 756 816 939 809 780 760 873
12 Pa 672 737 873 733 696 713 793
Difference of 84 79 66 84 47
Power (w) 0 Pa 66 63 52 52 62 53
12 Pa 64 62 51 50 60 68 52
Difference 2 1 1 2 2 2 1
Table comparison of 2 x-unit data
Export static 1 2 3 4 5 6
（m/n） 0 Pa 1213 1194 1186 1041 1178 975
12 Pa 1136 1101 1079 949 1086 913
Difference 77 90 92 92
Power (w) 0 Pa 106 102 91 93 83
12 Pa 103 99 89 91 90 80
Difference 3 3 2 4 3 3
4. national standard test method for noise of static pressure unit and installation requirements
4.1 when tested according to standards in air inlet duct connection experiment, adjust the external static pressure required (see Figure 1).
4.2 when the Hemi-anechoic chamber testing, measuring point distance reflector (ground) is greater than 1 m;
4.3 unit with connecting pipe segments should be tight no air leakage to ensure accurate detection of static pressure value.
Figure export static pressure unit of a noise measurement
5. According to the GB/T 19,232 unit in detection problems often encountered when
5.1 standard as in the past the lack of wind in third gear ratio of Unit requests and static pressure requirements of national standard unit must clearly third air static pressure value at the time. When the enterprise selection of motor, the wind in third gear ratio relationships does not have to adjust, some unit wind in third gear is almost no difference, while others are high and middle without pulling or low-grade is too small, these are not in line with user requirements.
5.2 in order to meet the export static pressure air flow requirements for 12 Pa, power should be simple, cause a although complied and the volume of cooling air volume is less than the rated value;
5.3 some units to allow for cooling to improve compliance without cooling coil, air flow over the requirements of the standard value too much, causing noise value is far greater than the standard value, the phenomenon is more prevalent;
5.4 choice of poor-quality motor, when detecting unit noise of static pressure requirements, motor a roaring noise;
5.5 unit selection of wind wheel size is too large or too small, and less than the static pressure requirements, selection of especially small wind turbine impeller should be more carefully;
5.6 on high hydrostatic pressure unit, at the time of Assembly screw holes, seams, water dish, coolers at the copper pipe and plate connection air leakage problems, some units at the time of high static pressure, air leakage rate by as much as 20%, it is recommended that manufacturers at the time of Assembly, pay attention to sealing problems of units.