Tag: caps


Service valves are so basic and we see them with such regularity that we can miss them altogether.

Before I give the tips I want to address the tech who tells the customer it was “probably the service valve” or “the caps were loose” as a plausible reason for a leak without actually doing a proper diagnosis. Don’t make excuses, find the leak.

Now some tips.

#1 – Look before you connect

Look for oil around ports BEFORE you connect your gauges every time. If you have a leaking schrader and cap you want to know that before you connect your gauges and eliminate that leak. Keep in mind that a service cap is NEVER meant to be the seal from a leak, it does act as an insurance policy against a tiny leak in a schrader. If you find a leaking schrader, replace it.

#2 – Be Gentle With the Heat 

No matter the valve make sure you protect it from heat when brazing or soldering (Here’s looking at you Staybrite #8 techs).

The schraders should be out when brazing anyway, but the internals of the valve are also sensitive to heat. Ever see a valve leaking from the stem? Odds are it was overheated at some point.

When opening and closing the valve DON’T CRANK DOWN so hard. We all know you are strong, but when you crank it open and closed like that you can over-compress and damage the seals and mating surfaces. Snug is good, if you need to “put your back into it” it’s probably too much.

#3 – Check Your Seals

A 1/4″ service port is actually just a 1/4″ flare fitting. Technically they don’t NEED a seal if the cap is a flare cap (think Trane brass caps). The only trouble with the brass flare caps is they do need to be on pretty snug to seal.

Most manufacturers have gone to caps with a rubber O-ring seal inside, they seal better and they only need to be finger tight. Before installing these caps get in the habit of checking the seal EVERY TIME. Make sure it’s there and that it’s in flat.

I have seen many leaks caused by an O-ring that got put in cockeyed and depressed the schrader slightly when the cap was installed.

#4 – Try the New Fangled Technology

We used to always advise using a bit of refrigerant oil when making flares and even when reinstalling the top caps on service valves. The oil doesn’t really “seal” anything but it helps you get a snug fit without twisting or damaging anything (the technical term is “galling”).

Trouble is, we are going away from mineral oil and toward POE and POE fouls if it is exposed to the air (humidity) for too long. Granted, a drop of mineral oil on a flare isn’t going to hurt a POE system but IT’S THE PRINCIPLE DANGIT!

I have raged against the use of thread sealants like leak lock in refrigerant circuits for years. I’ve seen teflon tape and leak lock on flare fittings and Chatleff fittings… Teflon tape and leak lock do not belong on refrigerant circuit components folks. They aren’t designed for that purpose and if they get in the system they are gonna cause issues. In many gases gumming up the threads and mating surfaces with these products can inhibit a good seal by getting between the flare mating surfaces.

A product I like is called Nylog it’s a very thick but constantly viscous product (never gets hard) and it won’t hurt the system if a little gets inside because it’s made of refrigerant oil.

You can put a drop on the threads and mating surfaces of all your flares, chatleff connections (the valve connections with the teflon seals), top caps on your service valves, pipe threaded ports…. everywhere.. but just a drop

You can also use it on your hose connections to get a better seal when pulling a vacuum.

Just use a small amount otherwise dirt will stick all over everything.

#5 – Using the Right Wrench and Back it Up 

For those systems that still use flare hex caps its best to use a 9/16 box end wrench or flare wrench (shown above) and use a backing wrench when removing the cap. All it takes is ONE TIME of breaking it off to regret using a big ‘ol adjustable wrench.

— Bryan

 

We’ve all been new at one time or another so there is no need to get all judgy about some of the mistakes new techs make just because they are inexperienced.

However…..

These are some very preventable mistakes that occur due to simple oversight and carelessness that need to happen 0% of the time.

Caps and Seals

Leaving caps off is never OK. While it’s true that Schrader valves and back seating service valves “should” seal completely and shouldn’t be left leaking it is always possible that a little leakage can happen. Besides, keeping bugs and dirt out of the ports is reason enough to keep the caps on.

Bill Johnson (co-author of RACT) made a really good point on a recent podcast. When a system is apparently low (which you can verify through non-invasive temperature tests) you shouldn’t just pull off the caps and attach the gauges. First, look for oil at the ports and leak check them to eliminate port leaks as a possible cause. Once you remove the caps and attach your manifold you won’t be able to know if the ports were a leak point or not.

Every time I remove caps I look inside them to make sure they are in place unless it is a flare hex cap that doesn’t require a seal.

It’s a good practice to keep all caps and screws together and in the same place on every call. This helps to ensure they don’t get accidentally knocked into the dirt, lost or forgotten.  Put those caps back on, finger tight for caps with seals and snugged up with a wrench for hex flare caps (Trane residential units for example).

Leaving Disconnects Out / Off

Obviously, nobody TRIES to forget the disconnect but it still happens all the time and it’s almost always because the tech gets in a hurry or distracted and usually both, and it can be eliminated easily by some best practices.

Most often the disconnect is left off or out during maintenance or during very simple repairs. This is because the tech will often run test the equipment, then perform the maintenance or minor repair and leave without run testing again. This order of test first then clean / repair isn’t my favorite for several reasons will silly mistakes being one of them.

I advocate for performing the comprehensive run test at the very end of a repair or maintenance meaning you are observing the system running right before you leave with the last action being resetting the thermostat or controls back to the desired setpoint. When you run test last you don’t forget silly things that prevent the system from running.

Always do a final walk of the job before leaving and check disconnects, setpoints, cleanup and check for tools.

Making Poor Electrical Connections 

I see it all the time. Capacitors tested and the spade connections left loose, contactor lugs not properly torqued, stranded wires with some of the strands cut off to make the wire fit, crimp connections on solid wire…. the list goes on and on. Here are the top mistakes to avoid.

  • When forcing on a female spade (on a capacitor for example) it should be very snug. If it is loose at all, pull it off and pinch down the spade sides a bit to ensure it’s a snug fit
  • When making a crimp connection only do so on a stranded wire and use an appropriately sized connector. Position the jaws so that the indent crimp is made on the side of the connector OPPOSITE the split in the barrel. Even better is to use a crimper specifically designed for insulated terminals that compresses the entire barrel.
  • Never cut strands of wire to make a conductor fit under a lug. Use the proper connection (termination) type for the conductor.
  • Never leave exposed wire, strip back insulation only to the length required to make the connection and no more.
  • Don’t leave connections under tension. Use straps and zip ties to keep tension away from connections so that they aren’t left under a pulling/disconnecting force.
  • Make appropriate connections for the job, never leave connections open to the environment unless they are rated for it.

When making any electrical connection always pull the connection to make sure it is a snug fit before walking away.

Failing to See the Obvious 

So much is made of good workmanship (how things look) and diagnosis (figuring out what’s wrong) and rightfully so. However, for a new tech, nobody expects you to do the best looking work out there or to diagnosis the super difficult situation. You are expected to use common sense and spot things that are out of the ordinary or that can lead to issues. Here is a quick list of things to look out for that you can see with little to no experience.

  • Look for refrigerant oil stains, often oil stains or residue can lead you straight a refrigerant leak.
  • Use a mirror and a flashlight and look for dirty evaporator coils and blower wheels. You may make a diagnosis but if you leave the system with a dirty coil or a blower wheel you still look silly.
  • Check the air filter and let the customer know you checked it. A home or business owner may not know much about HVAC but they know what an air filter is and reporting the condition back helps give them confidence.
  • Watch for rub outs on copper lines, feeder tubes, external equalizers and sensing bulbs and wires. You can often find or prevent a problem just by looking for areas of contact between tubes and/or wires.
  • Inspect control wiring for cuts or UV damage outside. If the weedwhacker doesn’t get the wire often the sun will.
  • Look for past workmanship that may be done incorrectly. Just because that fan motor or capacitor is new doesn’t mean it is the right size and wired properly. Always double check your own work as well as work done by others.
  • Before making a repair double check the previous diagnosis and check that the part you have is actually the correct part. There is NOTHING worse than removing a compressor t find out the one you have isn’t the correct one. ALWAYS double check the diagnosis and the part.

There are many other things that could be added to the list, but for a new tech if you do the following you will be on the road to success even if you are green.

  • Read product manuals and never stop learning
  • Listen carefully to senior techs and ask lots of questions
  • Help other techs when they are in a pinch
  • Smile and treat customers with respect
  • Compete with yourself to do each job better than the last
  • Walk  every job before you leave to make sure everything is buttoned up (Screws, caps, disconnects)
  • Ask every customer is you have done everything to their satisfaction and if there is anything you can improve.
  • Do all the little things with exceptional detail. Cleaning drains, washing condensers etc… always do it with a level of detail that exceeds your peers and you will build a reputation for excellence.

If you do these things your co-workers, customers, and managers will generally overlook the mistakes you make just because you are green.

— Bryan

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