What about 'the install' makes it as important, or more, than the equipment?
Newbie here, have been reading through threads for the past couple of days. I have noticed a common response to questions like "what brand A/C (and/or heater) is better/best?" I see many responses say that 'the install' is as important as the equipment. Could someone please explain what significant aspects of the installation are so critical? I know little about HVAC, so if technical, I ask that you please 'dumb it down' a bit.
Not that it probably makes much difference, but I have a 1995 Rheem outdoor unit and a Weather King oil burner of the same year. House was built in 1995 - I am the original owner. Guessing these were builder grade but don't know for sure. I have had 0 problems with either unit in the 17 years they have been running. Burner gets yearly service, A/C has not been touched since install. I'd like to get a replacement system installed before the outdoor unit takes a dump and I am forced to make a quick, uneducated decision about what to replace the HVAC system with. Only issue I have with both the outdoor unit and the burner are noise......... but the outdoor is located right near a corner of the house (which may amplify noise inside house?) and the oil burner has a Side-Shot (no chimney)...... so there may not be a simple fix to either. thx.
Let's start with airflow the most important aspect of HVAC especially as equipment has become more efficient. Next is proper sizing, even on an older home with an existing system never trust what is existing. Most homes I work on have too much capacity and inadequate ductwork. I looked at a home yesterday built in 1992 it has a 5-ton and has a 2.5-ton load. The return air capacity is only sufficient for a 2-ton and the supply ducts a 4-ton.
Once you have determined the proper capacity of the new equipment the components need to be matched to provide he correct airflow, heating capacity and the proper ratio of sensible and latent heat removal. Now comes installation practices which will determine the longevity and performance of the system. Starting with properly built and measured sheet metal ductwork connecting the components, sealing the ductwork so no air or minimal air is lost. Flowing Nitrogen through the copper line set to avoid oxidation, this is much more important with R-410A than it was w/R-22. The evacuation procedures are just as critical and a quality micron gauge needs to be used to verify the depth of the vacuum and that the system starts out dry and clean.
When all of this has been done a the airflow must be checked then the BTU's delivered proven and verified.
The first step is to see what you can do to improve your homes insulation & air leakage. Then move on to what Classical posted.
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Lets ask a simple question:
Would you take your NEW Lexus to the local dirty garage with a toothless redneck for major engine work?
The answer to the question is one word: QUALITY!
Some folks understand it... some folks can only see $$$... They BOTH get what they pay for.
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Quality work at a fair price with excellent customer service.
Nothing wrong with builder grade. With proper maintenance & installation.... looks like yours has lasted 17 years!
Check out how many systems in AOP are being replaced after 10 years or less!
I'll mirror what the others have said.
I will add- linesets must be clean & system dry.
New systems must be evacuated to under 500 microns & have a nitro sweep during brazing.
Seal ducts, properly support unit, correct air flow, system sized for the load, correct charge.
All these things should be done on every install but sadly it's not.
An install can make or break a system.
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Last edited by jpsmith1cm; 08-07-2012 at 04:29 PM.
The installers knowledge/training and expertice are important, but if they are told from above what to do, then all the experiance, etc. is out the door.
Originally Posted by drife678
My last place of employment was only interested in equipment replacement. The salesman had 0 (zero) knowledge of anything. He didn't even know what a TXV was. The boss told me, "what the homeowner doesn't know, won't kill them".
Besides the duct design and load calculation which should be done prior to the install, there are details that must be addressed by the actual installation technician. Purging with nitrogen while brazing the line set connections is rarely done but should certainly be part of any good installer's process (especially on 410a) line set design and installation is important for oil return and compressor longevity and so care should be taken not to create traps in the line. obviously kinks are a big no-no too. TXV installation - care should be taken not to damage the txv during the brazing process which usually means that the txv should be removed prior to the line connections and then re-installed (not always or even often done). I beleive that vacuuming with a micron gauge was mentioned. Simply attaching the vacuum for a perscribed amount of time is not acceptable. A standing pressure test should be done to ensure that the system is leak free, also. Unit and thermostat features should be set up to best meet your application. Some contractors don't even know the features of the unit which they are installing. The blower speed should be set (if psc) and adjusted against static pressure to ensure proper operation for comfort, compressor life, capacity and effeciency purposes. These and a few other details are all things that can be skipped by shoddy install crews and would be completely unbeknownst to an average homeowner. If these details aren't followed you could have problems. This is why it is so often said that the install (from application to installation) is more important than the equipment. Good luck!
When a system is being installed there are the big things that need to be done right, as already stated here, but there are the little things too.
proper electrical work
properly leveling the unit and correct support for both the indoor unit and the duct work
properly done pipe insulation and properly sealing the pipe insulation.
Another big one, touched but not explained, is brazing. Brazing is how two pieces of copper pipe are connected. A very large number of technicians are never taught how to braze right which causes extremely hard to find small little leaks that make you recharge your system once a year, oxidation in the lines, and many other problems.
What I try to teach my technicians and my customers is that HVAC is not just about refrigeration and cold air. It is a controlled system using physics and thermodynamics. An HVAC tech needs to be a plumber, electrician, lobbyist, teacher, engineer, salesman, aerodynamic engineer, thermodynamic engineer, and physicist.
This is why people who love this career love so hard. We have to wear a lot of hats and always learning more. It is also why such a high percentage of technicians are bad at the job.
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