Wireless Temperature Sensors for Better Controlled Temperatures

wireless sensors HVAC controls

Wireless temperature sensors make monitoring and controlling your HVAC system much easier.

Wireless Temperature Sensors for Better Controlled Temperatures

One of the most difficult issues a facility manager has to deal with is keeping the temperature within the building consistent. The building occupants complain that their space is too cold, while others may complain of excessive heat, making it clear that the temperature in your building is uneven. This doesn’t mean having to replace the entire system. By placing a few wireless devices throughout the building and minimal installation time, these complaints can be handled.

Temperature Sensing

Wireless temperature sensors are a great way to gain control over your building’s temperatures without opening up the walls and running wires for new thermostats. They play two parts, they not only monitor the temperatures inside the building, but also alert you if the temperature inside the building falls outside a certain range. Many of the wireless systems also inform you when the battery is low, saving you the trouble of waiting for the sensors to stop.

Wireless Sensors for Controlling Humidity

Being able to control the humidity throughout the building is another benefit that can be helped with the use of wireless thermostats. For some industries, it is a requirement to be able to control the humidity levels, for others it is simply a matter of keeping the occupants comfortable. It can also help during seasonal changes and when the volume of the crowd varies.

A building’s HVAC system works hard to keep the space comfortable. If the system isn’t working at top efficiency, you can install wireless devices to avoid the expense of having to install new wires throughout the building. Wireless temperature and humidity sensors and wireless thermostats can help fix the complaints that often come with building HVAC systems.

If your AC needs repair or service in LA or Orange County, please call Graves Heating and Air Conditioning Services, Inc. at 562-944-2118 to set up an appointment.

HVAC System Components

HVAC system components

A roof-mounted compressor is a common placement for commercial HVAC system components.

HVAC System Components

An HVAC system is a complicated collection of equipment that is responsible for controlling the interior temperatures of a home or building. However, most of these can be broken down into three basic HVAC system components:

  • cooling unit
  • condensing unit
  • refrigeration line

Cooling Unit

The part that most homeowners are familiar with is the cooling unit. Installed in a dedicated closet space, basement or attic, the cooling unit provides cooled air to the ducts that carry the air through the building. These functions are handled by the heat exchanger and evaporator coil located within the furnace.

Condensing Unit

The condensing unit is the workhorse of the HVAC system components. Located outside the building, a compressor condenses refrigerant gas that is cooled by heat exchange with the outside air. The refrigerant gas is converted to a liquid by the condensing unit and pumped through the refrigeration line to the main cooling unit inside the building.

Refrigeration Line

The refrigeration line connects the main cooling unit and the condensing unit.

All three components of the HVAC system are controlled by the thermostat, which is wired to the control mechanism of the cooling unit. By preprogramming the thermostat, the three HVAC system components can respond to the predetermined ambient room temperature and cool or heat the building accordingly.

If your AC needs repair or service, please call Graves Heating and Air Conditioning Services, Inc. at 562-944-2118 to set up an appointment.

Don’t Damage your AC System Trying to Make it More Efficient

ventilation ducts

Closing off too many AC ducts can cause damage to your compressor

This tip gives more details on why closing off AC registers can cause damage to your AC compressor and result in a huge repair bill. To read the original tip click here.

A 6 inch duct will carry 100 cubic feet of air per min (cfm). If you close off one register, you might be able to force 125 cfm through another 6 inch duct, but you have lost 75 cfm in the process. You can’t force all the air for the system through one duct. There is too much static air pressure. AC systems require around 400 cfm per ton. Closing off ducts can reduce your airflow to perhaps 300 cfm per ton. This is not enough to give full evaporation to the refrigerant. If this occurs, you can start to get liquid refrigerant into your compressor. Compressors have very low tolerance for liquid inside. The valves are very thin pieces of steel like the thickness of cardstock paper. When liquid hits them, it can break out chunks and cause holes in there. It just breaks them up.

Liquid refrigerant is also a solvent, so it absorbs oil. If you get liquid refrigerant in your compressor, it takes away the oil lubricating the compressor. You end up with an increase in friction, resulting in less efficient operation and probable damage and early failure of the compressor. Interestingly, refrigerant gas will carry oil and the designers rely on this property to lubricate the inside of the compressor whereas the liquid refrigerant will wash it away. You can see scratches inside the cylinder of a compressor where liquid refrigerant has run through it.

It’s very bad for the compressor to restrict air flow through the ducts of your AC system by closing off too many registers. Please exercise caution when closing registers.

If your AC needs repair or service, please call us at 562-944-2118 to set up an appointment.

How to Decide whether to Repair or Replace a Compressor

Commercial HVAC Unit, Graves Heating and Air, Rosa Media Productions

Commercial HVAC Unit Main Switch

Generally compressors are not the point of failure in a system. Many times the failure point is the electrical power and controls supporting the compressor. A compressor may not run, but doesn’t mean it is bad. It could also be burnt wires or a capacitor. These repairs are fairly inexpensive from the part point of view. The labor will be the expensive part of those repairs.

A compressor can be bad in 3 ways:

  1. The motor could be grounded or have open windings. It pops the circuit breaker instantly. The tech will need to check this with an ohmmeter.
  2. It could also be internal overload. This is a device that shuts down the compressor when it is running at high a temperature. This could indicate a low level of Freon or a dirty condenser. Not enough oil in the system can cause more friction, this could also result in an overheated compressor.
  3. A compressor could be a non-pumper – high suction, low discharge.

If a technician is telling you that your compressor is bad, you want to know exactly why. They need to do a pressure test. For instance:

If it is running 250/125 psi, that shows that something is mechanically broken inside the compressor.

If it is 300/20 psi, any tech should know that that is an expansion valve not a compressor.

Compressors get changed out all the time when the problem is not the compressor. It is some other aspect of the unit. Technicians really need to write down pressures if they are saying it’s a bad compressor, either not pumping or worn out.

If the compressor is still running, then you need a solid and specific diagnosis of the problem. If it is not running, then it has to be an open winding, its grounded, has a locked rotor, or it’s simply not bad. If it is not one of the above, it is probably a burnt wire or a capacitor, again, a much cheaper repair. A compressor not running has distinct causes, and the technician should be able to specify the problem in writing.

If your AC needs repair or service, please call us at 562-944-2118 to set up an appointment.

Let the Buyer Beware

Repair techs should clarify exactly what is wrong with your system before you move forward with repairs.

Repair techs should clarify exactly what is wrong with your system before you move forward with repairs.

Here are some consumer advocacy tips to help you keep from “being had”:

  1. How many flyers did you get last year for a $70 AC “routine” maintenance? That kind of deep discount offering is likely to be a fishing expedition for big ticket repairs. The fact is that it takes more than $70 to keep a typical AC repair truck and technician on the road for the amount of time it takes to do one-off “routine” maintenance calls. This is often the old bait and switch technique, so be careful.
  2. Expect your repair technician to specify the diagnosis of the problem before you spend any money for a repair. You can easily end up with a repair that is more than is necessary for the situation. Our technicians go out of their way to explain why a part is bad and to explain the repair needed.
  3. Don’t be afraid to slow down and get a second opinion.

If your AC needs repair or service, please call us at 562-944-2118 to set up an appointment.

4 Hot Tips on Thermostats

programmable thermostat

Thermostat technology has advanced greatly in recent years.

Thermostat technologies allow the home or business owner to optimize for comfort, efficiency, convenience, or some balance of the three.

Here are a few tips that relate to thermostats:

  1. Programmable thermostats allow you to keep the home at a temperature that is easier and quicker to cool than if you turn the system completely off while gone. Set your away time on your thermostat to the highest temperature you want to feel when you walk into your home.
  2. Thermostat technology has grown tremendously over the last few years. Units range from the old manual type, to units with daily, weekly, and weekend vs. weekday timers, to units that can be accessed and adjusted over the Internet while you’re away.
  3. Many brands are offering thermostats that you can control from a computer or mobile device while away from home. Be sure to buy one that is compatible with your system.
  4. When you are deciding on a new thermostat, consider how likely you are to actually set up and use advanced features before paying extra money for the latest and greatest technology.

Do you have a favorite thermostat tip? Please share in the comments below.

If your AC needs repair or service, please call us at 562-944-2118 to set up an appointment.

When to Buy a New AC Unit

Electrical cord strangling wallet

Time your AC replacement with a big repair need.

This advice is especially true for our older customers. You only want to buy one more unit in your life. The best way to only buy one more unit is to not buy it yet. Wait until you need a major repair like a compressor failure or a major freon leak. Don’t change it over a $200 or $300 repair. Change it over a $1,500 or $2,000 repair. The cost of that big repair can go into your new equipment.

We don’t recommend changing equipment just because it is old. Much of the old equipment was made from sturdier stuff than the newer equipment. What has been lost in strength has been gained in energy consumption. Today’s heating and cooling unit’s are much more efficient, but much more complex. All the “moving parts” like additional sensors, printed circuit boards, and the like make for more complex repairs.

Other factors to consider are: noise, environmental concerns, looks. You have to weigh in those factors into your decision. However, as a general rule, we do not recommend changing out equipment in lieu of relatively low cost repairs.

If your AC needs repair or service, please call us at 562-944-2118 to set up an appointment.

2 Signs that your AC Unit may be low on Freon

service and shut off valve on new AC condenser unit

Refrigerant is not consumed in the air conditioning process. If you suspect a leak, you should see if your technician can find it and repair it.

Refrigerant stays constant in your unit. It is not consumed during the air conditioning process. It only needs to be replaced when there is a leak in the system. Getting the ‘freon’ or refrigerant recharged in your system should not be a part of regular maintenance if your system is working properly. Two signs that your unit may be low on freon:

  1. You are not getting the 20 degrees difference between the supply and return air. See our tip on checking to see  if your system is functioning properly for more information on this.
  2. You see oil around the unit.


If you suspect that your unit requires a repair, don’t take a chance, give us a call at (562) 944-2118.

Important Reason NOT to Close AC Ducts for more Efficiency

AC vent

Closing too many AC vents can damage your compressor

Closing registers or supply vents is recommended by some as a way to save on energy costs. Unfortunately, this idea can actually backfire on homeowners if they close down too many vents.

AC systems are designed with a certain amount of air flow in mind. When a user closes vents, it reduces the amount of air flowing through the system. If too little air flows through the ducts and over the evaporator coil, the refrigerant fails to heat up and evaporate into its gas state properly. The amount of airflow is critical to boil the refrigerant from a liquid to a gas. It has to absorb enough heat out of the house in order to change into a gas.

If the refrigerant stays in liquid form and gets into the compressor, it can cause serious damage to the compressor. Replacing a compressor is usually an expensive repair.

Poor airflow can also result from a dirty filter. See our tip on changing your filter here.

If your AC needs repair or service, please call us at 562-944-2118 to set up an appointment.

6 Steps to Clean your AC Condenser

Clean your condenser annually. For most condensers this is simply a matter of hosing off the condenser unit. The units are a network of metal tubing and fins designed to dissipate the heat that your AC has removed from your house. You can usually find your condenser outside in the backyard. These units are designed to be out in the weather, but dirt collects in them. This cuts down on AC efficiency.

AC compressor

Clean your condenser annually to ensure better AC performance

To clean your condenser, follow the steps below:

  1. You will need a garden hose, a spray nozzle and a water source.
  2. Turn off electricity to the unit. The disconnect is sight of the unit.
  3. Do not disassemble the unit for cleaning.
  4. Spray the unit vigorously across all the fins but be careful not to spray directly on the motor.
  5. Look for large chunks of spider webs or leaves getting stuck and not coming out. Sometimes spraying water from another angle will break those up so they will wash away.
  6. The unit will dry itself.

This type of cleaning can be done by a trained professional, or you can have your installer or service technician show you how you can do this yourself. Always keep the area around the condenser free of debris so it will have proper airflow.

If your AC needs repair or service, please call us at 562-944-2118 to set up an appointment.