About Tim McAuley Expertise can answer general questions on air conditioning & heating. cannot answers questions on appliances.
Experience 19 yrs wholesale distribution of refrigeration & A/C equipment and related parts, 1 yr manufacturers representative for air conditioning & heating equipment, 10 yrs manufacturers of A/C & Heating equipment, 3 yrs with contractors as a mgr of service & sales. Currently employed with a manufacturer of heating & cooling thermostats for residential and light commercial applications.
Education/Credentials high school, some college. Many industry related schools & seminars, manufacturers education programs.
Question QUESTION: hi I have two questions :
1- I received a complete 3 Ton A/c system,but I found that the coil{evaporator) has 2ton rating ..what should I do ? change the evaporator to 3ton or reduce the refrigerant charge?
2-In 2ton A/C residential what size of fan I can use?
300cmf or 400cmf or what?
ANSWER: Sam - I don't know your circumstances, or why you received a 3T condensing unit with a 2T evap coil, but you should match the tonnage up between the condensing unit & evap coil. By reducing the refrigerant charge, you will damage the compressor which is designed to handle a certain amount of refrigerant. In addition, the unit will be very inefficient and cause you more problems than it's worth. So, 2T evap coil should be matched with a 2T condensing unit. 3T condensing unit should be matched with a 3T evap coil.
You need to know what capacity unit will provide you the right amount of cooling when it gets hot outside. That can be determined properly only by having a load calculation run on your home. A licensed contractor should be able to provide that for you (at a cost), or a design/mech. engineer.
A general "rule of thumb" we use in So. California is 400 sq feet per ton. That is not the proper way to size an a/c system, but some contractors do. In Arizona where it gets extremely hot in the summer, that "rule of thumb" changes.
As far as cfm goes, use 400 cfm per ton. So a 2T system requires approximately 800 cfm.
Good Luck
Tim
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QUESTION: I am working in servicing residental air conditioning,I want to know how to mount the sensing bulb for TEV on the evaporator suction line when replacing the metering device(TEV),if is not mounted securely to the suction line(become loose) how that will affect the superheat?
Answer Sam - The TXV bulb should be securely mounted to the tubing at the evaporator outlet. If it is loose it will not be able to feel the temperature accurately and, therefore, the valve will not feed the evaporator properly. It is preferrable that the bulb be mounted on a horizontal line. If you have to mount the bulb on a vertical line, make sure that the cap tube from the bulb is going upwards and not downwards. Tightly secure the bulb with a hose clamp or wire ties.
