ACI Northwest Blog: Archive for December, 2011

A Question from Worley: What Does a Furnace Fan Limit Switch Do?

Friday, December 9th, 2011

When researching your Worley home’s furnace and potential problems it might have, you’ve probably run across a few references to the fan limit switch. And while you know that it can break in a number of ways, do you know what the switch does and what you should look for when checking your furnace its air handler for problems?

What the Limit Switch Does

To put it very simply, the furnace fan limit switch is a control that tells your furnace’s fan when to turn on and off. So, when the furnace isn’t on, it tells the blower not to operate (and send cold air into your home) and when the furnace is on, it tells the blower to turn on and start circulating the warm air.

While the primary function of the limit switch is to turn the blower fan on and off, it also has a safety role. When the temperature in the air supply plenum gets too hot, the limit switch turns off the furnace boiler to keep there from being any damage from overheating. This is handy if there is a blockage in the air vents or the controls are messed up due to water damage or improper adjustments to the settings.

Looking for Problems

Most of the time, when there is an issue with your furnace turning off or on frequently, the limit switch is one of the first things you will check. Because the switch is electronic and is attached to a thermostat which measures temperature in the air supply plenum, a small problem can result in it not working properly. So, you can easily check it by temporarily bypassing the switch and seeing if your device turns on or off properly.

In many cases, if the limit switch is the problem, you will still need to call a professional for replacement, but you can avoid a lot of headaches related to tracking down the source of the problem. If you suspect a limit switch problem, make sure to call someone immediately, because it does provide an important safety function and because without it your furnace won’t cycle on and off properly.

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High Efficiency Furnaces and Chimney Concerns in Mead

Wednesday, December 7th, 2011

When upgrading to a high efficiency gas furnace, you may need to make some upgrades to your Mead home’s chimney. Older chimneys built for standard furnaces with normal exhaust needs are not built to the specifications needed by today’s high efficiency models. Not only is it unsafe to leave it as is, but the cost of repairs if you don’t have it upgraded can be substantial.

Down-Sizing

A common concern when upgrading to a high efficiency gas furnace is the issue of condensation and draft. Because the amount of exhaust being vented is reduced by a high efficiency furnace, your current setup is not sufficient for the new model. So, it needs to be reduced in size by a professional to avoid backup of exhaust. Proper chimney sizing is a complex process that requires professional guidelines and careful measurements of all appliances in your home.

Because the chimney often isn’t used at all for a high efficiency furnace (often PVC pipe used instead), the extra airflow in the chimney can become a major issue.

Chimney Condensation

The biggest concern for the chimney when changing the furnace efficiency is condensation. Specifically, acidic condensation droplets can build up in the chimney if not properly stopped. A new chimney liner must be placed in the chimney to avoid excessive corrosion due to the acid droplets. Keep in mind that the efficiency of your new furnace will determine whether you will use the traditional chimney for exhaust or if a new line will be installed to vent your furnace.

When to Take Action

If you have your furnace replaced, your technician will likely discuss the chimney situation in your home with you. Keep in mind that this might be necessary and that there might be an added cost involved because of it. Modern furnaces are not designed to accommodate aging chimneys and your safety and the integrity of your house are at risk if you don’t retrofit the chimney if necessary.

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Hope HVAC Contractor Tip: Poor Heating Performance with Your Boiler

Monday, December 5th, 2011

You don’t have to be a rocket scientist or a Hope HVAC contractor to troubleshoot – and possibly diagnose – the problems with your boiler when its heating performance is erratic or non-existent.

The good thing about boilers is that they are typically reliable and long-lasting. There aren’t a lot of working parts that can break down and cause problems, compared to other home heating equipment. When problems do arise, they are usually related to the expansion tank or circulating pumps. But a problem can be much simpler – like a tripped circuit breaker.

The most common problems can be noise, no heat, or poor/erratic heating. Before calling a heating contractor, take a moment to see if you can figure out the what’s wrong.

If you have a noisy boiler it might be because of two things – a faulty circulating pump or water trapped in the return lines. If the pump breaks it will make a loud noise when its motor runs. Water can be trapped in the return lines, which may require “re-pitching” the lines to allow for a flow back to the boiler. You may be able to adjust the flow by positioning hangers on the piping but replacing a pump is better left to a professional.

If your boiler is producing no heat, it could be because of something as simple as a circuit breaker being tripped or a fuse being blown. Check your circuit breakers and fuse and reset or replace if necessary. Is your boiler thermostat in the heat mode? It should be but if it isn’t, make the switch. If your boiler has a standing pilot you should check to see if it is lit and if not, re-light it.

Other problems would take a professional to fix. For example, no heat can be traced to low water levels in the boiler. The boiler should always be half-full of water and if it isn’t, it is likely because of leaks or a faulty pressure reducing valve. Don’t try and fix the problem by yourself.

Low water levels may not cause the boiler to lose its heating capabilities, but may cause fluctuations in its heating capacity. Again, it is advisable to call a professional to diagnose and fix the problem. Poor heating can also be traced to mineral deposits in the boiler. Consult your owner’s manual on instructions how to flush out the boiler.

As always, read the owner guide or operating manual for your boiler. You should get some good tips on proper maintenance and troubleshooting. And have the phone number of a qualified professional taped to your boiler – just in case.

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How Heating Zone Control Can Save You Money

Friday, December 2nd, 2011

The costs of heating your Rathdrum home have risen dramatically over the past couple of decades, thanks to higher energy costs and price increases for heating equipment. Despite the strides made in energy efficiency, there seems to be no end in sight for the steady rise in heating equipment operating costs.

Now add in the cost of heating unoccupied areas of your home, such as basements, hallways, or extra bedrooms, and the energy costs go even higher. Most of these costs are unnecessary and avoidable if you have the time and a small investment in a well-planned heating “strategy” for your home. This strategy involves using heating zone controls to make the most efficient use of your heating system.

In a nutshell, here is how heating zone control works. The rooms in your home are connected to your heating system by a series of ductwork, which carries heated and conditioned area to all corners. But some of these areas may not need to be heated as much – or possibly at all – compared to other rooms in your home. For example, do you need heat in your kitchen but not in your basement? Most people would answer yes. Or they may say they need more heat in the kitchen and some, but not very much heat in the basement.

Or try this: do most people in your house spend more time in one room, such as the family room, and less time in their bedrooms? If so, why would it be necessary to heat the bedrooms all of the time? In order to deliver heat to areas in your home that need it the most, the ductwork to these rooms should always be “open.” Ductwork to other unused areas of your home can be “closed” during various times of the day.

Opening and closing of ductwork and airflow is achieved by zone controls. A zone control is installed in the home which electronically or wirelessly opens and closes “dampers” in the ductwork, depending on the heating demand. You can divert heat to areas of your home using zone control and dampers while decreasing the heating load on your furnace. This type of heating zone control will move heated air to where you want it. Simply put, you are not heating areas of your home that don’t need the heat.

The heating zone controls can be programmed for various times of the day, too. For example, you may not need any heat in your basement while you sleep or when you are away from home. You can program the damper in your basement’s ductwork to remain closed or partially open during these times. In a sense, the heating zone control in your home acts like a programmable thermostat – only it uses a series of dampers to control indoor temperatures.

The next time you walk into an unused part of your home, think about how much money you are spending to heat it. It makes sense to consider heating zone controls. The initial costs of installing zone controls and dampers are minimal and the payback in energy savings and comfort are substantial.

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