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: How is the size/diameter of the refrigerant lines determined? Is it tonnage, SEER, or something else?
ANSWER: Ray - Line sizes are determined by the amount of refrigerant and velocity required thru the tubing to meet the requirements needed for whatever application is being used. If the lines are too small for the compressor displacement and pumping volume, or too large, the system won't work properly and damage will occur. Refrigerant has to maintain a certain amount of velocity and density as it passes thru the system to do its job. So, because everything is related, seer, tonnage, line size, etc. the how or why is arbitrary.
A 4 ton system typically uses a 3/8"-1/2" liquid line and a 7/8" suction line. With the new refrigerant being used now (R410A) there may be instances where an old system line size may not be ideal for a new R410A system and may have to be changed.
Hope that answers your question.
Regards
Tim
---------- FOLLOW-UP ----------
QUESTION: Tim - I live in an 8 year old south Florida CBS construction 2450 sq.ft. home with a 5 ton, 10 SEER unit. I am trying to educate myself prior to replacing the existing with a more efficient - 15 to 18 SEER - unit. Does this give enough info? Only the SEER is changing.
Answer Ray - Not sure what you are asking with your follow up question.
If you are replacing your whole system, consider going to a minimum of 16 SEER, 13 EER. Heat pump systems it's 15 SEER, 12.5 EER. The fed govt is giving a 30% tax credit, up to a maximum of $1,500 for these ratings. Make sure that the contractor shows you that the system he proposes to install will make the tax credit.
Does your current system cool the house down comfortably? Does it struggle when it gets good & hot out? If so, ask the contractor to run a load calculation on your home.
* Use a licensed & insured contractor only.
* Get 3 quotes.
* Get the details written into the quote, what he proposes to do.
* Find out the warranty of the equipment and what are the warranty terms, such as, do you have to register the system online with the mfr.
* Get his warranty for labor in writing and what his warranty covers beyond his labor.
* Ask him why he's proposing the brand of equipment he is, and what makes it better than other brands.
* Make sure he explains to you how the system functions. Most likely it will be a 2 stg or variable speed cooling system. They operate differently than current systems. Should make less noise.
* Try to get him to include an extra year of labor free warranty.
* Get him to include a winter start up for heating operation. He comes out & starts up your heating system for winter operation at no cost.
* Try to get him to include a high efficient filter. ( not cheap fiberglass)
* Make sure his work includes the inspection and repair of ductwork problems.
Can't think of anything else right now. Got to get back to my work.
