Welcome to our first Blog post Hopefully, the first of many....
Well folks its getting to be that time of the year again. The trees are slowly changing color and losing their leaves, the evenings are slowly getting cooler and our attention starts turning toward staying warm and cozy in our homes. Netflix marathons and other solid reasons to hibernate and it is easy to see why so many people feel comfortable tucked in at home at this time of the year.
It recently dawned on me, just how much we take that mystery box in the basement or attic for granted. Of course I am not referring to your secret stash of whatever it is you wish to keep secret surreptitiously tucked away in the rafters, or stealthily hidden behind the hot water heater. I am of course talking about our furnaces. We ask a lot from these mysterious machines. and your average homeowner is as mystified by their heating equipment, as a caveman discovering fire for the very first time was.
In the summer we call upon our furnaces to keep us cool and in the winter, nice and warm. We ask this without so much as a second thought. Turn the dial on a thermostat and we expect an almost instant result.. That is of course, unless you have been unfortunate enough to suffer through a mechanical breakdown in either season....Not fun and can be quite costly to boot.
I think we have all been guilty at some point or another, of furnace neglect, skipping an inspection, or forgetting to change the filter on a regular basis... At least I know I am guilty as charged. Either intentionally or unintentionally,of committing such furnace related atrocities. I am sure I am not alone here either. especially since there seems to be so much going on this time of the year. What with. Halloween thanksgiving and ultimately Christmas right around the corner, it is easy to lose sight of the important maintenance tasks around the house.
A Furnace inspection in my humble opinion, is a necessary evil.... Just like going to the doctor or or getting your oil changed..But did you know, an annual furnace inspection can actually save you money? As an example, a dirty furnace can run between 10% and 25% less efficiently than a well maintained furnace. bottom line...a dirty furnace will cost you more to operate..which is part of the reason why, it shouldn't be overlooked.
An inspection if properly executed, will also catch any potential issues before they arise.. Something as simple as a dirty flame sensor, can leave you shivering in no time. So its best to have your furnace professionally checked before each and every season.
Well you might ask, what does a good furnace safety inspection consist of.? I thought you would never ask....
Depending on the age of your furnace, a good quality furnace inspection should consist of at least 15 points, including the following. (*caution Furnace maintenance should only ever be performed by qualified service personnel*) we do not recommend you try this yourself unless you know what you are doing. there are dangerous voltages present inside your furnace, which pose a risk of injury or even death.
1. Check the igniter by using an ohmmeter. Measure the resistance through the igniter. If the furnace has a silicon nitride igniter, you should see 11 to 17 ohms. If the furnace has a carbide igniter, you should see 50 to 100 ohms. If the reading is outside these parameters, the igniter should be replaced. Remember that you need to test the igniter when the igniter is cold and furnace is not firing..
2. Check and clean the flame sensor (if present). Hook up your multimeter in series with the flame sensor and the sensor wire. Fire the furnace into the heat cycle. Your readings should be 1.5 to 4 micro amps (some manufacturer’s control systems only need 0.5 micro amps, so check the manual for the system you’re testing). When sensor tests at less than 1 Micro amps (or less than 0.5 micro amps on some systems) you’ll see nuisance problems, and soon it will stop sensing completely.
3. Pull and clean the burners. The most common failures associated with burners are contamination and misalignment. Many of today's in-shot burner designs incorporate the carryover mechanism into the burner itself. There may be slots or "wings" in the burner, which align with the burner next to it. Inspect these to make sure they’re free from debris that could disrupt the flow of gas and air.
A stiff brush can be used to clean superficial rust or soot from the burner face. Use air pressure to blow out the burners and burner vestibule area. A dirty crossover can cause delayed ignition, which in turn can cause high carbon monoxide (CO) on start-up and during the first 60 seconds of operation,. Replace severely rusted burners.
4. Inspect the heat exchanger for excessive rust, cracks, or holes. Visual inspection is always the best, but requires training and practice. There are tools available to assist, such as inspection cameras and dye penetration inspection systems. Inspect the metal flue for rust or holes, and make sure it’s supported properly.
5. On condensing 90%+ furnaces, clear the condensate line. Remove or blow out the P-trap and pressure tubes to remove debris. Condensate lines have become the source of a common issue for 90%+ furnaces: long run times in very cold weather can cause the pressure switch to lock out. Then, by the time the service technician gets to the house, the water has drained out and everything is working again. This is one of the little items that can cause homeowners to become frustrated when they pay for a cleaning and problems like this occur.
6. Check the system static pressure. Determine if you're working on a system with a non-variable-speed motor or a variable-speed motor. A system with a non-variable-speed motor will have maximum design total external static pressure (ESP) of 0.50-in. water column. A system with a variable-speed motor will have a maximum design ESP of 0.80-in wc. On an 80% induced-draft furnace you need 130 cfm or cubic feet per minute of supply air, per 10,000 Btu. On a 90% furnace you need 150 cfm of supply air per 10,000 Btu. Refer to a fan chart to set the correct cfm for the furnace so you can complete setting gas pressure and proper heat exchanger temperature rise (if the system has a bypass humidifier, make sure you close the damper during this process).
7. Read and record the temperature in the supply and return plenums. The supply air plenum temperature on condensing and induced-draft furnaces should be 60F warmer than the return air temperature; the difference on a natural-draft furnace should be 75F. The flue temperature should be 170F warmer than the supply air plenum temperature on an 80% induced-draft furnace, and on a 90% condensing furnace it should ideally be equal to or greater than the supply air plenum temperature.
8. Check and adjust the gas pressure. Gas heat content is lower than typical design. Manufacturer’s installation manuals for natural gas furnaces list the maximum Btu' per hour input, which assumes a certain heat content in the gas at 3.5-in. water column manifold pressure. The best way to measure the gas pressure is to clock the meter to verify that the orifice is the proper size and you can set the correct gas pressure (note that it isn't possible to clock a meter with an LP furnace). Furnace manufacturers typically list in their installation manual for natural gas that a range of 3.2 to 3.8-in. wc is needed for proper combustion because of the variation of gas Btu content. As it usually isn't very easy to have the proper assortment of burner orifices, you can typically achieve proper combustion for maximum safety and efficiency by adjusting the gas pressure.
9. Check for gas leaks. You can use either soap bubbles or an electronic leak detector, but keep in mind that some electronic leak detectors will produce a false-positive from certain brands of pipe dope and soap bubbles.
10. Look for proper support of the vent pipe. On condensing furnace installations, low spots will accumulate water and retard venting, possibly resulting in trips of the pressure switch. Pipe-support hangers should be placed every 3 ft. on PVC. Also inspect for leaking or loose fittings. If the PVC exits the side of furnace and has a rubber boot attaching the PVC to the inducer, be aware that boot isn't designed to support the pipe and should have a support strap directly outside the furnace.
11. Set the heat-off delay. For best reliability and maximum efficiency, set the heat-off delay to the longest time available, which is typically 180 seconds.
12. Lubricate the blower motor (Where applicable). Most modern furnace blower motors are sealed and require no lubrication, they do however tend to get "Gunk" around the shaft and bearings. This if left uncleaned, can cause the blower motor to draw more amperage than a clean motor should. This is why it is important to remove any dirt and debris from around the motor shaft.
13. clean the Furnace vestibule. Some people may argue this point with me and say it is not necessary. but, as my dear old Mum would say, everything should be "ship shape and Bristol fashion" meaning everything should be clean and tidy. My reasoning for this part of the inspection is this.... A dirty furnace vestibule will harbor dust, which can be sucked into the burners during the combustion cycle or end up on the motor shaft and bearings. Either way not good. a good cleaning with a shop vac and or slightly damp rag will go a long way here.
.14. Clean or replace the air filter. This is kind of a no brainer as they say.... The importance of changing or cleaning your furnace filter every 60 days, cannot be understated. Even if the filter looks clean, it should be changed religiously and without fail. I find it easy to remember to change the filter by setting a recurring reminder on my smart phone or PC. The furnace filter is the lungs of your system, without proper airflow the system will labor to get the job done, causing it to use more power and ultimately cost you money.
.15. Check electrical connections. Furnaces are subject to both extremes of temperature and in some cases vibration too. Either way this can be bad news, especially if you are an electrical connection. Changes in temperature cause metals to expand and contract add vibration and your connections could work lose over time. this is why, this step should be an integral part of any annual furnace inspection..
These points should ensure that you have a safe an trouble free heating season. We hope you found this post useful and or informative. Please leave us your comments questions and thoughts on today's blog. If there is a particular subject you would like us to write about just drop us a line.
Apologies if this post was a little long,...
Britannia Home Services
Hi My Name is Bruce Kenny and I am the owner and founder of Britannia Home Services. I am married with 3 kids and reside in Naperville Illinois.