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Any one familar with gasket material selection out there? I am specifing the material of a water box gasket with max. pressure 150 psi and max temp. 130 F. Looking for advise on the following properties: hardness per ASTM2240, Compression set 25% compressor per D395, creep relaxation. Thanks...

Hi, folks, I have a question regarding wire sizing per NEC. UL requires hazardous voltage circuit conductors supplying one motor shall have an ampacity not less than 125% of the motor full load current rating. Does NEC have the same requirement? I found ampacity table 310-16 &17 in NEC 2005...

Hi, I am designing the defrosting system for a box @ -18 C. I installed one solenoid valve on liquid line and another one on hot gas line. Do I need to put one valve (check valve or solenoid valve) on discharge line between compressor and condenser inlet? I checked a few books and found it was...

Hi, Where could I find a pressure relieve valve with setting 15-25 psi (for air)? Thanks,

Hi, I am designing a freezer with eletric defrost heater. Cooling capacity 1,000 btu/h at 5 F box temperature. How much is the power I should put in the heater? I know it depends on a lot of factors such as moisture of the load, defrosting cycle etc. But I need something to start with and do...

Hi, I am looking for a pressure regulating valve that will keep the downstream pressure at 10-15 psi. Anybody knows where I could find it? Only small amount of nitrogen will go through the valve. Upstream pressure 100-300 psi. Thanks,

Hi, I am looking for a pressure regulating valve that will keep the downstream pressure at 10-15 psi. Anybody knows where I could find it? Only small amount of nitrogen will go through the valve. Upstream pressure 100-300 psi. Thanks,

Hi, we are planning to convert the refrigerant of a cascade system from R23 to R508B (Suva 95). Is it necessary to change the expansion valve? Thanks,

Does anyone know whether I can use Castrol Icematic SW32 for my Bitzer 4H-25.2 (recip compressor) and R23 (HFC for cryogenic application)? Unfortunately, it is an old installation and I lost contact with the compressor manufacturer. Thanks if anyone could provide some input.

Hi, I am designing a direct drive system including an electric motor and a 6 -cylinder reciprocating compressor. How much is the service factor I should use when I size the key and coupling hub/spider (because of the vibration)? Thanks,

Hi, I am new to the commercial and industrial heating business in North America and have some questions. Is boiler using coal very popular in North America? Or is oil or natural more popular? I am reading a book about stationary engineer and the book says stationary engineers have to look at...

HI, Everyone, I am working on an mobile air conditioning system and needs an R134a compressor that has best efficiency when pressure ratio is 2:1. Is a scroll compressor more efficient than piston at the pressure ratio? Thanks,

Hi, Everyone, We are developing a small AC system for vehicle and need compressor about 40cc using 134a. I searched web and found most of the compressor are 80cc and up. Is there anybody who knows the compressors I am looking for? Thanks,

Hi, everyone, I am trying to find a program to perform a least squares curve fit with a ten coefficient equation. z=c1+c2*(x)+c3*(y)+c4*(x^2)+c5*(x*y)+c6(y^2)+c7*(x^3)+c8(x^2*y)+c9(x*y^2)+c10*(y^3) Does anyone know where I could find the program? Thanks in advance.

Hi, I am having hard time to find a heater coil manufacturer for vehicle climate control as I am more familiar with commercial heating and cooling. I need a serpentine coil manufacturer, not a fin and tube coil manufacturer. Could anyone tell me who I can turn to? Thanks in advance.

Does anyone has rule of thumb regarding how to compensate for the oil in the refrigerant when sizing the condenser and evaporator? Say I have a compressor has 3-6% oil carry over (% of mass). Thanks,

Limited by my experience, I am adding a part list on the drawing by draw the table using LINE command, putting individual text in the cell using MTEXT command. Then I have to adjuct the location of the text in the cell to make the table look nice.It takes a lot of time. Is there any better ways...

Hi, I am new to Autocad. When I used Leader Command to link an object with a balloon (I left Text empty). The leader came with a tail. I gather it is not the right way to do the job. How should it be done? R2004 Thanks,

Hi, I need to plot a lot of drawings with R2004 but the objects were drawn with yellow line. As you could find, you could hardly see the objects on printed paper. Is there any way to fix it other than change the color of object in model space for each drawings? Thanks,

HI, Everyone, When working in Autocad 2004 paper space, I was trying to use object snap in model space to precisely locate a point but could not make it. Could anyone tell me if I should be able to do that? If not, is there any other way to precisely locate a point in paper space? Thanks,