Homeowner calls and explains that there is no heat, the air was working fine until we switched over to heat when it got a little cool this fall. We collect as much information as the homeowner can provide before we begin our repairs.

1. We had problems recently and the Service Company installed a new Thermostat.

2. Heat has never been used since then.

3. When we called for heat, nothing works at all now.

Our actions:

The first thing we noticed was exposed wiring at the air conditioner thermostat wires. These were addressed one of the very first things. The weather had deteriorated the insulation on these wires and it was very possible that they had contact with each other so we clipped each wire and eliminated problem areas.

Then after checking the proper voltage in, we began to look at all components and wiring. Looking for any obvious burnt or broken wires or any thing at all that does not look right.

In this case we looked at the wiring on the thermostat one of the very first things. All wires were color coded and seemed to be in the right place and we began to dig deeper.

In the air handler we as stated above inspected for obvious problems. The 24 volt output fuse was hidden under some wiring and it was open or should I say blown. Okay so our immediate thinking is all we have to do is replace this 50 cent fuse and all will work fine. Well you guessed it. NOT

This was only the beginning of a three day affair. It was discovered that between the air handler and the thermostat there was a clump of wires that had been connected with wire nuts. So we clipped away and checked for shorts back to the thermostat. The wiring seemed fine so we rewired properly and proceeded.  Back to the air handler and we disconnected the second thermostat wire out to the air conditioner to isolate the heat form the air. At this point we would check each leg of wire and all components and add new fuse and call for heat and these fuses are beginning to add up. Of course this is not the right way to do this testing, however we wanted to protect the 24 volt transformer and this was the only way we could insure protection here.

Long story short we discovered a weak contactor that was replaced with a spare we had on the truck. It was also discovered that there was a hairline crack in on leg of the bladed contact point on one heat strip. Of course the thinking was that this might be a possibility of why this fuse is still blowing. After cleaning up and soldering the hairline crack, we called for heat again. POP the fuse blows again. This is near a giving up point. Then it came to me that well there is no reversing valve on the air conditioner so I’ll just eliminate the orange wire on the thermostat and the unit as it is not necessary. Pop yes you guessed it.

I hate to be whipped in situations like this. I called in an Electrical Teacher form a local Technical College. After he went thru a couple hours of the same testing that I had already been thru, it was determined that we had a bad thermostat. Remember we had info that there was a new thermostat installed recently. So with this info we went to supply house and picked up new thermostat and back to make the final repair.

Installed new thermostat and called for heat and “POP”.

Now this is personal. Rechecked the thermostat wire a second time. clipped and basically looking for a needle in a haystack. Isolated the heat from the air again and this time we installed the thermostat and called for heat. Checked the wiring at the air handler with meter and was sure that what we would or should find is three wires that were activated with thermostat.

1. red 24 volt supply

2. green/fan

3. white/heat

This should be all it takes to make the air handler operate in heat.

Well the blue wire was also called by thermostat and this is where all the problem with the fuse wound up being. Because blue is the common on this unit in the low voltage supply it was overlooked as necessary at the thermostat.

We removed the blue wire from thermostat, hooked everything back up and called for heat and after four days of troubleshooting the thermostat and heat got along together.

Still a small problem now with the air conditioner, fan works but compressor does not. The blue wire was necessary to the unit outside to complete the 24 volt low voltage circuit that pulls in the contactor.

So after much discovery and relentless determination to get this family some heat we have this system operational and some much needed maintenance that was taken care of in the discovery of the fault.

Also it should be noted that there was inadequate wiring diagrams onsite. Even the internet was very vague and we were unable to find the problem with diagrams that we had found.

Problem: 24 volt low voltage output fuse keeps blowing.

Solution: Removed blue wire from thermostat.

Which One Is Which?

Call comes in from Joe and after the brief greeting Joe ask if you would like to take a look at an HVAC unit that is causing problems on a Commercial building with twenty units. Yes Sir I’d be glad to take a look. Exchange of information includes the following:

1:Suite G Air Unit just quit working Friday and address to building.

It is your first visit to this location and you might think it would be real easy to find the problem to the Suite G unit. That’s the easy part. The problem is where is Suite G’s unit at and where is the main power source deep within the building. The owner probably knows this information, however may not be accessible when needed, so this is now the Repair Technicians problem.  So getting to know the individual system is just the beginning.

Keep in mind there are twenty units not just one involved. Each unit most likely has a disconnect real close to it’s proximity. But where is this power source from? The main power source seems to be a problem as well as something going on in the unit that has caused the total failure.

This actually happened to me recently and it is probably something that every HVAC company has experienced. So it is important for the Owners and the service companies alike to have some sort of sketch, diagram, or means of identifying each of the units on-site.

In this case I will after completion of all pertinent information on diagram, have several copies made and laminated. Distribute for possible posting at a location for the HVAC Company to be directed to in the event of a problem with any unit. This will allow the Technician to grab a waterproof copy and go about his work.

With todays technology this simple diagram can be used in many formats that can easily be included into a mobile app, tablet for viewing. For more advanced in depth information about each unit, one could use a CAD program to create many layers of information to include photos, text files, the list goes on.

Simple works.

So a simple hand drawn diagram will help in the future with the HVAC units at this location. After a couple months and many other similar situations, it is so easy to forget where a particular power source is for say Suite G. It saves time which equals $$$ if your new HVAC Repair Service can go directly to the Unit and it’s pertaining sources. So take the time and have an informational diagram for your HVAC Service Company. It will cost in the front end to do this, however you can see the savings from every visit in the future from another company or technician that is not familiar with your site.

Numbers were added to each unit to correspond with each Suite. With this simple little fix, it is now possible for a Technician that has never been onsite to pick up a copy and quickly make it to his destination without to much input from the owners.

Refrigeration is Refrigeration. Right?

Which One Is Which

Well yes and no. Not all systems are the same. On a call that has several commercial units on the roof of the building and several units @ ground level. What can I do to familiarize myself with each system, so I will be able to address a particular unit and diagnose a problem without re-inventing the wheel every call?

A new client and 15 units. Client calls and says I’m having trouble with Suite G. It just quit working. You make it out to the site and it is very difficult to determine which one is suite G. It’s possible that you begin to diagnose the wrong unit. How embarrassing is that?

Well kinda like never trusting someone else to turn off the current. “Hey Joe, did you turn the current off.”  Yes says Joe. You insert screwdriver and a arc from Hell melts the tip of your screwdriver into oblivion. You yell, “Joe I thought you turned it off.” Joe says “Oh I thought you said turn it on.” Well you get the point.

1.Find out as much about the problems or symptoms from whomever can provide you info on when it quit, what happened, how did it act, did it show previous symptoms that led up to it’s total failure. It will also be helpful in most case’s to have them show you all thermostats, electrical boxes, units, access points. etc.

Now we are ready to start. With all info gathered I figure that I have a good idea of what I need to do next. So the process of elimination starts. I soak up all info I can and then don’t put 100% trust in what info I have is right.  Now it’s up to in the field experience as to what I do next. Or maybe even in-experience.

After several hours and checking all the maybes and what ifs, I have a general idea of this particular system. Now I know which of the very large electrical boxes deep within the building and several hundred feet from the H.V.A.C. unit has the faulty 30  amp cartridge fuses that are being blown with every throw of the switch.

After diagnosing the problem and fixing the unit, it is only now, that if I had to do the same thing again next week with the same unit would I know right where to go and what to do.

Familiarize Yourself With The System.

So that is why I say every system is different. The homeowner or client sometimes may not understand that a ten minute fix may take several hours to  diagnose and perform. Many of the problems are the same but location of electrical panels, faulty wiring, bad components, neglect, and shoddy work from former repairmen often take awhile to diagnose.

2. Take some time with today’s technology and itemize the H.V.A.C . units on a large building like I have mentioned. Label them so it is easy to get to the right unit, easily. A-1, A-2, A-3, Suite B, Suite 4, Suite C, again you get the idea. A simple .txt file with some photos in a directory named Client#1 is simple and will really help next time you have to go out to that particular site. A brief notation of what was done on that unit in Suite G may simplify and save you a lot of time which equals money. The more $$$ you save your clients the more satisfied clients you will have.

This is simple experience that may help you in your H.V.A.C. needs as a customer or as a Technician.

Stay Safe, It’s Up To You. Not Hey Joe

Drair

In order to test a cartridge fuse, you will need a multi-meter. With the tester on turn the dial to ohms on a lower setting. Place one end of lead on either side of the fuse. If the fuse is good, the tester should have little or no resistance showing on the meter. I tested several today and they all measured 0.5 ohms. If the fuse is bad, you’ll see an infinite reading, meaning the fuse link is blown.