Troubleshooting Electronic Zoning Systems

Zoning is a great enhancement to a HVAC system. However, there can be some bugs in implementation if you are not vigilant during installation. Problems we face during service calls normally fall into two classes: 

1. Something is intrinsically incorrect in the application or installation.
2. There is a problem in the system’s operation or a component.

There are two main zoning system types: electronic and pneumatic. The difference lies in how the dampers are closed and opened. The blog discusses the best way of troubleshooting electronic zoning systems.

Start by checking the system first:

Start with checking how the system is performing during full airflow, with all blowers running and dampers open. This is also a good chance to verify that the dampers of the zoning system are not stuck.

After you have confirmed full airflow, observe the result after shutting down a zone. There has to be considerable increase in the air delivery in the rest of the zones. Also, there should be absolutely no more air transported to the zone that has been shut down. Repeat the same test for all of the zones.

Problems you may find:

System zone board

Most of the system zone boards come with an onboard diagnostic LED. Analyze it for potential trouble codes.

Board failure is not a common occurrence. Therefore, when it occurs it is very important that you find out the reason rather than simply swapping the board. For instance, a poor wiring work can be one of the biggest causes of board failures. Another reason behind board failure is inadequate power. Most experts advise that a separate 24V transformer be utilized to power the system. Has a separate transformer been used in this case? Was the transformer sized according to the size of the hardware connected?

Input sensors

These are utilized for measuring return and leaving air temperatures. In case a low or high temperature trip has taken place, did the input sensor reset? What system operation has to occur for causing the sensor to trip? Are you aware of the trip temperature points? Incorrect placement of sensors can also cause trouble. Is the air sensor located at a place where radiant furnace heat can instigate nuisance trips?

Orphan zones

While two-zone designs permit us to fragment system capacity, a third or fourth zone can lead to unintended consequences. For instance, you have a system where zone one takes 35% of the conditioned space, the second takes 40%, and the third zone is 25%. What’s the likelihood of a glitch in the system with merely twenty five percent of the system calling? In case the system obtains a call for operation from only the third zone, the enhanced noise level and air delivery can lead to complaints.

A zoning system helps multiple thermostats to turn off and on the same system; sequence cool, heat, and fan calls. Troubleshooting a zoned system requires knowledge of the logic of zoning. It is best to contact a skilled technician to service a troubled zoning system if you are not well versed with your HVAC. 

How to troubleshoot a gas furnace?

A gas furnace is a piece of equipment that takes in cold air, uses an air filter to clean it, heats it with the help of a gas burner and distributes the warm air through the ductwork. The heated air helps to increase room temperature during the cold winter days. Furnaces come with different efficiencies. However, once in a while these appliances may not work quite right and you may have to troubleshoot them. 

Let's look at the most common problems you may have to face with a conventional furnace.

Gas Furnace does not produce any heat:

Possible causes:

1. Thermostat not working
2. Propane or natural gas control valve is closed
3. Circuit breaker or fuse that is controlling the gas furnace is tripped or blown

Best possible repairs:

1. Check if the thermostat has the right temperature setting
2. Try to move the dial setting down or up a few degrees
3. Clean contacts in a non-digital thermostat
4. If the circuit breaker has tripped, reset it
5. Relight the standing pilot light

Blower is always running:  

   

Possible causes:

1. Thermostat has been fixed to run fan continuously
2. Defective control switch for fan limit

Best possible repairs:

1. Change the fan setting on the thermostat
2. Replace or reset furnace fan control switch

Gas furnace produces less heat

Possible causes:

1. The air filter is dirty
2. The gas burner is dirty or requires adjustment
3. Air flow is blocked to the combustion air chamber

Best possible repairs:

1. Clean or replace the dirty air filter
2. Call a professional service provider to get the burners adjusted.
3. Make sure the furnace has enough combustion air.

Noisy operation of gas furnace

Possible causes:

1. A "squealing" sound caused by slipping motor or shaft bearings or blower belt that requires oiling
2. Slight "rumble" when the burner is off may be caused due to wrongly adjusted pilot light.
3. Slight "rumble" sound when the burner is on is caused by dirty gas burners.

Best possible repairs:

1. Use a light weight oil to lubricate the blower motor lubrication ports located at the end of the shaft
2. Check for correct belt tension. If it’s loose, make sure you tighten the belt.
3. Adjust pilot light
4. Replace frayed belt
5. Call a technician to get the burners cleaned or adjusted.

Pilot light is out

Possible causes:

1. Dirty orifice, a strong draft, or dirt inside the gas tube can lead to a pilot light going out.
2. A faulty thermocouple may also shut off the supply of gas.

Best possible repairs:

1. Ensure that your thermostat is on "Heat" mode.
2. Find the pilot.
3. In case you have a pilot that has a red Reset button, turn "Off," the gas valve to "Pilot."
4. In case you have a pilot that has no red button, turn the dial from "Off" to "Pilot."
5. Depress the knob or hold the button and light the pilot using a lighter.
6. After the furnace burners ignite, regulate the thermostat to the preferred setting.

Sometimes your gas furnace may act out and may require repair. You can follow the tips mentioned above or call a technician to fix the problem. If the issue seems complicated, it is best to seek professional help.

Tips to help you work with a contractor

Working on your house and performing home repair can be extremely rewarding. However, there will be times when you may not have the inclination, time, or skill to do the repair.  This is when you should hire a contractor. This blog will help you decide when and how to choose a home maintenance or repair contractor.

Decide if you really need a contractor

Deciding to use a contractor is often personal. Here are a few things you need to evaluate before making the decision:

1. Your level of comfort with the project at hand;
2. Your budget;
3. Your time.

If the task is beyond a simple home repair and involves complicated technical installations such as adding a sink or adding electrical circuits then you must first check if you need a permit from a local building department. You will not need a permit for certain home repairs but may require permission for “new work” particularly for heating, electrical, plumbing and cooling. In certain cases, permits require that a skilled, licensed contractor does the work to protect the public’s safety, health, and welfare.

Choosing the right contractor

This may be the toughest task but it’s actually pretty straight.  A great tip is choosing contractors you may also need on an emergency basis before you need them.  This is because if you have an urgent repair and are trying to find a professional quickly (who is also fair and skilled) you will not have the time to go through a very lengthy screening/ selection process.  And the most unwise thing you can ever do is choose someone from the Yellow Pages.

One of the best ways of selecting a possible contractor is by getting references from family, friends, or even a trustworthy realtor.

Evaluating the estimate

Getting bids from a subcontractor or general contractor should be based on the scope of work. Evaluate the estimates on the basis of similar scope. Let’s divide bid evaluation into categories and address every single component individually.

Scope of Work

This will define what the professional is going to do for you. Make sure it covers everything you want. It must be able to spell out any prep work, clean up, and safeguarding surrounding areas, etc.

Evaluating the scope of work of different contractors is essential. For a HVAC expert, try negotiating a fixed price. We advise you to pre-select an expert for emergency tasks. However, expect to pay extra for emergency calls on such repairs.

Choosing the right contractor will help you keep your HVAC system in perfect condition. However, if you feel paying a professional will cost you too much then make sure you are well prepared to take up the task in hand. Either way, it is best to be prepared!

Troubleshooting a high efficiency furnace

A high efficiency furnace is a high technology machine that enables you to heat your house while consuming low energy. However, like any machine it can at times stop working, and when this happens it normally requires calling a ventilating and heating repair shop.

However, before calling an expert, there are a lot of things that you can check or repair on your own.

Thermostat:

The thermostat that controls your high efficiency furnace should be the first thing you check. You must check to see if the machine is operating properly. Some of the possible problems include:

• Fuse blown or circuit breaker is tripped
• Dirty thermostat components
• Loose wires
• Bad battery

Clogged filter:

A severely blocked furnace filter can create a lot of damage.  It can also cause the machine to overheat and frequently cycle the safety switch on and off. Check the filter which is either a paper media or a fiberglass furnace filter or a state of the art pleated paper media filter and make sure you replace it if necessary.

Once you have replaced the clogged furnace filter, turn off the furnace switch for a few minutes and then turn the switch back on. This will help in resetting the furnace electronics.

High limit switch:

A high temperature limit switch is basically a safety device that screens the temperature of the internal furnace and shuts down the gas valve if temperature limits exceed. As soon as the temperature decreases to the lower limit, the gas valves are turned back on turning on the burner.

It is possible for the high temperature limit switch to suffer damage if it is subjected to frequent tripping because of low air flow and overheating. You can use a multi-meter to test the switch.

• Set the multi-meter to resistance.
• Evaluate the wires travelling to every switch terminal.
• In case the resistance is 0 Ohms then the switch can be regarded as good. On the other hand, if the resistance is infinite the switch needs change.
• It is easy to replace the switch. All you have to do is unscrew the switch plate and change the replacement part.

Obstructed vent pipe:

Another problem that can stop the furnace from functioning properly is an obstructed or clogged flue vent pipe. An obstructed flue gas vent pipe can also make the pressure switch to trip.

Make sure the pipe is sloped properly and is free of obstructions.

Hot surface ignition:

In normal conditions the hot surface ignition will last for three to five years. However, it will have to be replaced eventually, quicker if the oils from your skin get on the element by improper handling.

The HSI achieves 1,800°F to 2,500°F of heat. Once the right temperature is attained, the gas valve opens, introducing gas to the burner which is then ignited by the HSI. Once the flame sensor senses a proper flame, the HSI shuts down.

Knowing your furnace will help you keep it in the best condition possible. However, it is important to get in touch with experts if you find it hard to correct the issues.

The various types of home heating systems

Your house may have one of the many types of home heating systems. These can range from tubing hot water through your flooring to propelling hot air from ductwork.

Whichever type of heating system you choose to have, it will have several benefits and drawbacks. So it's a good idea to have a quick review of how some of the popular home heating systems work and their advantages and disadvantages.

1. Forced air cooling and heating system:

This is the most common form of home cooling and heating system.

Distribution:

Air is heated inside a furnace. It is then distributed from the furnace through ductwork and in the rooms.

Advantages:

• It is the only distribution method that can also be used for cooling
• Air can be humidified
• Air can be filtered
• Inexpensive
• Air can be dehumidified

Disadvantages:

• Takes a lot of space in the form of ductwork
• Moving air may distribute allergens
• Air needs regular maintenance and filtration.

2. Radiant heat:

This system helps in providing the most comfortable and natural heat inside a house. It comes in a variety of forms, from an in-floor hot water piping to pot belly stove. It functions through a process of direct transfer or radiation of heat from a hot surface to a cold surface.

Advantages:

• Even and comfortable heat
• Energy efficient boilers

Disadvantages:

• Slow heating process as it takes time for the surrounding materials to get warm
• Expensive installation cost
• Difficult to maintain.

3. Hydronic:

Very much like radiant heat, the hydronic system makes use of hot water to heat a room by a combining convection and radiation.

Advantages:

• Quiet
• Energy efficient
• Temperature control

Disadvantages:

• Baseboard convection/ radiation units should remain unobstructed and might provide challenges in placement of furniture and drape design.
• Slow increase in temperature.
• Air conditioning requires a different ductwork system.

4. Steam radiant

Steam radiators are not as popular in this day and age. They have cast iron upright radiators that radiate steam and heat. Steam radiants are of two types, two-pipe and one-pipe systems. With one-pipe, steam and water travel in a single pipe but in the opposite direction. In the two-pipe system, while the steam runs in one pipe, water condensate tends to return in another pipe.

Advantages

• Warms the room quickly
• Comfortable

Disadvantages

• Radiators are unappealing
• Radiators may restrict furniture placement
• Air conditioning needs a separate ductwork.

5. Boilers

Boilers are heating plants that are used for creating steam or hot water for hydronic baseboard, steam radiator heating systems or radiant heat. They may use a range of different fuels such as, propane, natural gas, electricity or oil.

Hot water boilers are normally compact, small, low maintenance and energy efficient.

6. Geothermal

Geothermal is the newest heating and cooling technology. Geothermal heat pumps work like refrigerators that have the ability to run in reverse. The heat is basically taken from one source and then deposited in another area. Geothermal Heat Pumps have the ability to save up to 30 to 70 percent on heating and approximately 20 to 50 percent on the cooling costs in comparison to conventional systems.

Knowing your heating system helps you keep it in the best condition in turn helping you keep the maintenance costs low.

DIY Air Conditioner Maintenance

Your air conditioner is an expensive and complex piece of machinery and needs professional care and service to keep it working properly and to extend its working life. Any compromises here could increase the chances of major fault developing and the resulting large repair bills. That being said, there are a few simple actions you can take to keep your air conditioner clean and in good condition. You don’t need to be an HVAC expert or have any special tools to do this. A little common sense and a few basic tools that are found in all homes are all that is required. Here are a few things that you should do once a month during the season that the unit is being used. The specific location of the components mentioned below will vary depending on the type of air conditioner installed and the make. Your user’s manual will have diagrams and details of where the components are.

• Turn off the power: Before doing anything, always turn off the power to the unit by tripping the circuit breaker. This ensures that you are safe from the risk of electrical shocks.
• Clean the compressor: If the compressor is covered by a thick layer of dust and grime, it will run excessively hot and this will increase the chances of it failing. The compressor is one of the most expensive parts of the air conditioner and replacement will make a big hole in your pocket. Remove the dirt with a brush.
• Clean the condenser fan: The fan get dirty easily and besides the layers of dirt placing an extra load on the motor, the air circulation is also affected. Use a brush to remove the dirt.
• Lubricate the fan motor: If the fan is noisy or has developed a vibration, remove the fan from the motor by unscrewing it. The oil ports for the motor should be visible. Lubricate the motor using the oil given in the user’s manual in the specified quantities.
• Service the air filter: A dirty air filter will collect fungus and bacteria and circulate it. The airflow will also be restricted leading to loss of cooling and more load on the unit. Remove the filter every couple of weeks, and wipe it with a clean cloth. Then wash it with nonabrasive soap and water. Allow it to dry completely before reinstalling it.
• Clean the ducts: Use a vacuum cleaner to clean dust and debris from the ducts.
• Check the connections: Check the fuses, breakers and visible wiring regularly to catch loose connections and incipient short circuit issues before they become major ones.

These are all basic maintenance tasks. They can, at most, supplement the regular maintenance that should be done by an HVAC maintenance company. If you are in doubt on how to go about them, or feel that there is a specific problem that needs to be addressed, call an air conditioning expert to check the unit and attend to the problem. Remember that the best way to keep you air conditioner running well is to have it maintained by experts. Also keep in mind that if a unit that is not serviced regularly it may consume excess electricity and inflate your utility bills.

Learning how to troubleshoot your central air conditioner

Central air conditioner units can work without problems for years if serviced and maintained properly. In case they don’t work properly, call up a skilled technician. However, before making the call, make sure the problem is not just a minor glitch that you can fix on your own.

The unit stops to work:

If you get your system cleaned and inspected annually, it must run with no trouble. However, if the air conditioning system stops working and you are not sure why, troubleshoot the problem before calling a professional:

1. Check the fuse box or circuit breaker to find out if the system has power.
2. Check the fuses near the condenser, to ensure there’s power.
3. Clean or replace the furnace filter.
4. In case the condenser coils are covered with debris or dust, clean them off with a garden hose.

The unit won’t stop running:

If the system won’t quit running then here’s what you should do:

1. Turn the thermostat up.
2. By setting the thermostat a little higher, you will save a lot of money on energy bills.
3. Take the lid of the condenser off and check if something is blocking the flow of air.
4. Vacuum the condenser’s interior, and then clean it with a garden hose.
5. In case the fan blades are dirty or bent, clean them or get them straightened.
6. Check the blower and furnace filter to see if there is any blockage. Make use of a vacuum cleaner to clean the dirt and dust around or on the blower.
7. Get the filter replaced if required.

The system freezes:

In case the high pressure lines from the evaporator coil or furnace to the condenser are iced up, then make sure you shut the unit down:

1. Either pull the switch outside or turn off the breaker within the control panel.
2. Call a professional for help.
3. Water begins to pool below the evaporator

In case there is water under the evaporator, the drain may get clogged. Although it can be cleared, the best thing to do is to replace it.

1. Take the trap off, and in case it’s plastic, cut the pipe and do away with it.
2. Pour bleach-water or a vinegar-water inside the drain. This should help in removing algae and debris.
3. In case you have flexible tubes, clean them. You can also use a wire to scrape the tube walls. Make sure you perform this maneuver gently.
4. Reassemble the trap and tubes.

Although its isn’t rocket science to troubleshoot a central air conditioner, if you find the whole procedure tiring and cumbersome it is best to hire an expert to do the job for you.