Dave's Tech Tips

  • R-22 Retrofits  We are in the New Year and the one thing we can be sure of is that the price of R-22 will continue to climb. The EPA still hasn’t decided how much production ... read more
     
  • Head Pressure Controls  We can feel that the temperature is dropping outside and we have moved into the heating season. Though we are swapping our gauge manifold for a manometer, many A/C and refrigeration systems will still be expected to ... read more
     
  • Non-condensables in an AC System  Non-condensables are gases that will not condense into a liquid within the operating temperatures of the refrigeration system. Air and nitrogen are the most likely non-condensables we will see. Air can enter ... read more
     
  • The A/C TXV  The TXV being installed on most A/C systems is a very simple devise that has only a couple of moving parts. They are very reliable and will operate trouble free for years if installed and maintained properly. Overheating the ... read more
     
  • Up Sells  Usually you sell that new equipment, install it, and move on. However, there are a lot of add on items that you might be missing that can easily be sold on every job and not only increase profits but also add value for ... read more
     
  • Conversion considerations for HFCs and POE  HCFCs like R-22 may cause elastomeric gaskets and seals to swell or harden. When the R-22 is removed and replaced with any of the HFC replacements, drop-in or other, gasket and seal shrinkage may occur. This shrinkage of gaskets and seals may cause leaks to develop after the retrofit is complete. This shrinkage is not caused by ... read more
     
  • Have You Seen The Price of R-22?  As you may have noticed by now, the price of R-22 has gone way up! The short version is that the EPA is speeding up the phase down R-22 production. By how much we aren’t sure yet but the price is climbing. What are our options in ... read more
     
  • Transformers  In the HVAC industry we commonly use Class 2 control transformers to lower the voltage to 30 volts or less, with a power rating of 100VA or less. This allows us to run low voltage wiring outside of an enclosure without ... read more
     
  • Silicon Carbide or Silicon Nitride igniters  The Silicon Carbide igniter that has been used by furnace manufactures for a long time is old technology that hasn’t changed much in almost 60 years. They are very fragile, and will break very easily. Grease or dirt can The Silicon Carbide igniter that has been used by furnace manufactures for a long time is old technology that hasn’t changed much in almost 60 years. They are very fragile, and will break very easily. Grease or dirt can ... read more
     
  • OEM or Aftermarket?  A long long time ago…when I was new to this business, a furnace had a gas valve, pilot, thermocouple, fan limit control and blower motor. I carried all of these on my truck and rarely did I have to leave the job to get parts. As advancements have ... read more
     
  • Why can’t I charge with a sight glass alone?  When working on a refrigeration system that uses a TXV you normally have a liquid receiver. This liquid receiver stores enough extra refrigerants to properly feed the TXV under any load condition ... read more
     
  • Compressor Burn Out  There are many things that can cause a motor burn out in a compressor. The best way to clean up after a burn out is to prevent the burn out from happening in the first place. Things such as moisture, non-condensable and overheating are preventable causes of ... read more
     
  • Accumulator or Receiver, That Is The Question  The tank on the suction line between the evaporator and the compressor is a suction accumulator. The tank on the liquid line between the condenser and TXV is a liquid receiver. They do look similar but they serve two completely different ... read more
     
  • Which TXV for A/C?  When should a TXV be used and how do I select it? TXVs for air conditioning are pretty much the same as TXVs for refrigeration. They work off of bulb pressure that opens the valve and increases refrigerant flow to the coil. A combination of adjustable spring pressure and suction pressure ... read more
     
  • I Have Frost On My Suction Line!  Though refrigeration and A/C share the same basic cycle and many of the same components they also have many differences. Frost is a big difference. Normally an A/C coil temperature stays above freezing. Frost on an A/C coil tells ... read more
     
  • Hard Start Kits  Most single phase A/C compressors are PSC (permanent split capacitor) motors that have low starting torque. For many applications this is ok because the pressures have a chance to equalize during the off cycle so only low starting torque is required. Though most PSC A/C compressors don't come with ... read more
     
  • What do we know about flare fittings?  As the mini-split market continues to grow we are finding ourselves working with more and more flare connections as most of the mini-splits use them. A lot of us agree on one thing with flare fittings, they leak! Having worked in the commercial refrigeration industry for many years myself ... read more
     
  • Why do we use a pump down system?... An outdoor refrigeration condensing unit will normally operate no mater how cold it gets outside. If the room thermostat simply de-energized the contactor to cycle the compressor off we would run into refrigerant migration problems.  During cold winter months the refrigerant ... read more
     
  • Zerol Ice becomes A/C Renew... First of all what is Zerol Ice? Zerol Ice is a lubricant that was developed by Shrieve Products Company, manufacture of Zerol alkybenzene refrigeration oil. Though it is a complete lubricant it is designed to be mixed with existing refrigeration system oil at a ... read more
     
  • To flush or not to flush...  When replacing R22 A/C systems with a new R410A system do we really need to flush or clean the old line set if you plan on reusing it? The answer to that is yes, absolutely! For starters we need to...read more
     
  • What is a CPR?  A CPR or crankcase pressure regulator is nothing more than a pressure reducing valve. When installed on a compressor suction inlet and properly adjusted, the CPR will prevent the compressor suction pressure from ever rising above the CPRs setting. The CPR will help...read more
     
  • Why are you adjusting that TXV?  To answer this question we first need to look at the main functions of the TXV. The TXV is designed to keep the evaporator as full of saturated refrigerant as possible while at the same time protecting the compressor from slugging or overheating. This is accomplished by...read more
     
  • Vacuum Facts:  When is the last time you changed your vacuum pump oil? If you had to scratch your head it has been way too long! The oil in your pump absorbs the moisture and non-condensables that you removed from the system. Only clean dry oil will allow your...read more
     
  • Where did the silver come from?  Have you ever noticed that when you clean a condenser coil with acid or “red” coil cleaner the fins turn a shiny silver color? The caustic cleaners, like the red acid coil cleaners (hydrofluoric acid), actually etch or remove a tiny layer of aluminum while cleaning, leaving the fins shiny silver. It looks good but after a coil has been cleaned many times... read more
     
  • R12 is still around - It has been over 15 years now since R12 was phased out, yet Tecumseh’s second best selling unit is still the AEA4440AXAXC which is for R12! Not many of these units are installed with R12 but with one of the many “drop in” R12 alternative refrigerants. R134A, the HFC R12 replacement (like R407C which replaces R22) requires...read more
     
  • Oil creates acid and alcohol - POE oil is very hygroscopic and absorbs moisture like a sponge. POE will absorb 10 times more moisture then Mineral oil, which makes it much less forgiving. When POE oil has absorbed enough moisture it will break down into acid and alcohol that will attack...read more