Sunday, January 26, 2014

Amana and Goodman Downflow Furnace Control Board Fix.

Unless you are a competent service technician, I would not attempt this procedure at all. However, you may be able if you are a homeowner to clue in the clueless in case your tech is having trouble figuring this out. God forbid he or she is, but it will help nevertheless. As always, I have zero control over the quality of your work. Using tools and working around electrical always has some risk of death, injury, or property damage. Improper service methods can damage expensive parts and compromise the safety and integrity of the equipment you are working on. Make sure you shut off the breaker or switch at the handybox before working on any equipment.
Amana, which is now owned by Daikin, still shares many mechanical and electrical components with Goodman, save that Amana has a stainless steel heat exchanger. Their products are screwed together pretty well, and the materials are decent, but even they can make a mistake once in a while. This one affects their downflow furnaces with the green cabinet made through the late 2000's and possibly beyond. The vintage of this unit is 2008 and like many of these units, they are plagued with intermittent operation that can confound the most seasoned of services techs. Eventually, this furnace will flat out not operate, requiring lots of troubleshooting when it is least convenient.
Usually this is one in the morning with 0 degrees Fahrenheit with -20 wind chills. The problem starts in this case from the factory with the placement of the control board. It's placed on a panel covering the heat exchanger and with time, this heat will damage the board.  You'll need a new board, a 1/8 drill bit and a drill motor, needlenose pliers, a screwdriver and a marker with a fine point.
This is the original board in the factory spot. Note the discoloring cater corner from the main wiring harness.

Here it is from the back. This is damaged.


You need to remove the old board by squeezing the standoff clips holding it to the panel and gently lifting it up. Since the new board doesn't have any clips included, you will need to reuse the old ones. Using your pliers and a screwdriver, carefully pull the clips from their holes at an angle to avoid breaking them. Use the screwdriver to gently pry as you pull them. Put the clips into same box as the new board. If you want to remove all the wires first, you can use the old board as a template to drill four holes into the side of the cabinet to mount the new board. If not, carefully use the new board as one. Make sure that you locate it away from any screws as pictured above and all the wiring must be able to reach the board in its new position. You may need to position the board on the outside of the cabinet to make your marks where the inducer will get in the way of your drill. Carefully drill holes from the outside of the cabinet without hitting anything inside. Once you drill the holes, install the standoff clips to the new board as pictured below.



Transfer each connection from the old to the new board. If you mounted the new board correctly, you can hook these up easily; you may have to remove a zip tie or two to get the wires where you need them.

 
Tie any wires back that could be resting against hot or moving parts including where the old board was mounted at the factory. This was given to me from Goodman's tech support 4 years ago. I've been using it ever since, even on furnaces that haven't had symptoms yet. Another hint: if the furnace won't come on, but if you gently push in the center of the board and it works for a moment replace the board. When you're satisfied everything's connected, turn on the power to the unit, set the thermostat and cycle it to make sure it doesn't need any more work done to it. Thank the customer for the work, hand him or her the invoice and you're done. The customer will be amazed at your skills. Maranatha! :)

Saturday, January 18, 2014

Pushing the Limits on a Lennox

When I tell a customer and discuss it with the coworkers and the boss about a furnace that's oversized, I don't expect to hear from that customer again. However, today I did and this is getting old real fast. The complaint was a 1999 Lennox Model number G23Q2/3-75-1 that was cutting out every time the homeowner, an 85 year old woman, put the filter in. The furnace has a manual reset limit for the heat exchanger, as shown below.

I tested the gas manifold pressure, it was at 2.88 inches of water column (I know this is low). The static pressure was .08 inches of water column at the supply before the A coil, and -1.08 after the filter (admittedly, I'm not the best with this). I inspected the blower wheel and A coil for dirt and debris and they were clean. The opening for the A coil was 6 inches by 12 inches with a plenum that is 21 inches wide by 21 inches deep. The supply ductwork is a transition from 20 inches by six inches into a 6 x 6 square heat run at the rear while the front is a 16 x 7 piece. The return is a 16 x 6 piece hooked to a return drop with no transitions, the return drop is 20 x 8 into a 14 x 20 inch drop elbow. The furnace is 75,000 BTUs with a 60,000 BTU bonnet capacity (this is the heat available to the homeowner that doesn't go up the chimney). The house is a bungalow with 8 foot ceilings that measures 38 feet by 25 feet for a total of 950 square feet not counting walls. There are six heat runs, a double return and two single returns on the main floor. The basement has four heat runs and a trunk cut as well as a return. The heat rise was 71 degrees in the plenum and 92 degrees in the heat exchanger. The temperature was 175 degrees when the limit tripped.

So this is what I'm dealing with, and the customer says this furnace hasn't caused her any problems until recently (of course) while my field supervisor with the utility company wants me to replace the limit. One of my coworkers also echoed this sentiment two weeks ago. My contention is that replacing the limit will buy us another month or so. I've been doing some figuring and a furnace with an induced draft blower at 75,000 BTUs needs 975 CFM or cubit feet per minute of air to run properly. This is found by dividing the output by 10,000 and multiplying the answer by 130. The house also needs about 1 CFM per square foot, so this is pretty decent as airflow goes.

Now for the ductwork: The return is 16 x 6, which is about 450 CFM, which lower than what this furnace needs. Even at 60,000 BTUs it would still need 780 CFM, which this ductwork can't provide. I would need a return that is 18 x 8 to compensate for this at 60,000 BTUs. The supply duct is 16 x 7 at the front, which is a little over 500 CFM, which is going to be restrictive, but not as much as the return. To put this quite mildly, I'm frustrated. a house this size should need no bigger than a 50,000 BTU furnace, which at 80% will have a 40,000 BTU bonnet capacity. Even a 45,000 80% with a 36,500 bonnet capacity should work more than fine in a 950 square foot house. 60,000 is way overdoing it and looks to me that the installer read the plate off the old equipment, rather than doing his due diligence and doing an actual load calc on the house. At least he could have attempted to size the furnace by the square footage. Now I have a customer who is going to resist every attempt at common sense over what she already has, because in her words, "it hasn't given me any trouble until now." Problem is that this furnace is giving me plenty of trouble in the here and now, and it seems those in charge don't give a damn about it. They'll make up every excuse; tell me it's the right size and "just put a new limit in it." Problem is that swapping parts will not help and in a week, month, or even a year and me or some other poor soul will be back here again, fighting the same problem. In the meantime, it's time to try and get the tire tracks to the bus off my backside. Maranatha!

Update: I installed a new limit in it and it's been in about a week with no callbacks yet. Per the policy of their company, they'll assign someone else if the repair lasts for more than 30 days. It's an auto reset, which came with the furnace from the factory (happily I was wrong). It still doesn't excuse the installer, and hopefully she gets a new furnace or this part holds up for a while.

Friday, January 17, 2014

Old Water Heater, and Condemned A Nordyne Today.

I'll try and get pics on this water heater, but it was installed in 1953 making it 61 years old and was original to the house. Yes, it did finally leak and the customer is going to replace it next week. The Inspector camera has claimed yet another victim. This time a 21 year old Nordyne furnace in Lansing, MI. The original complaint was that the furnace would take a long time to light. Since this used a glow bar, my first thought was that it was going off on pressure switch. I drilled a hole in the side of the plenum with a step bit and within two minutes found a hole the size of a quarter in the heat exchanger. Carbon Monoxide or not, I had to shut it down.  Even though the customer ended up buying from someone else, this camera is a godsend and has saved me countless hours trying to diagnose problems when the furnace is a lost cause. Even though the homeowner is always upset, the fact that they know the problem and the fact that you have saved a life is a good thing. Maranatha!

Sunday, January 12, 2014

A Short Compilation of Venting Issues.

This furnace is also accompanied by a water heater. Neither are vented up to code; even though the homeowner, an 80 year old woman, swore up and down that her installer son did this right. What she needed was a flex chimney liner which is code in my neck of the woods for an 80% efficient furnace with a vent motor. The condensation and acids will eat up a chimney as these vent gasses are not hot enough to get these acids out.

Supposedly, this was installed by a licensed contractor. Note that the vent pipes are taped, not secured with screws. There's a piece of 5 inch single wall into a 4 inch Bvent elbow into a 4 inch single wall pipe. If he was licensed, why not pull a permit?

 Okay, the picture of the water heater shown above isn't just a venting issue. It says right on the side, "for mobile home use". So why am I picking this apart? What few people realize (and I was guilty of this in my house) is that mobile home water heaters come in two versions, inside and outside accessible. These are also known as natural vent and direct vent (not to be confused with power vent water heaters). The direct vent water heaters go inside of a closet and have a sealed combustion intake that feeds under the floor and are almost always in double wides. The natural vents in a mobile home are supposed to be installed in a mechanical room accessed from the OUTSIDE only. If you install a natural vent in this fashion, it will suck all the air out of your living space and even if it doesn't, it won't stay lit or work properly. The homeowner told me that a weatherization company installed this water heater two years ago, but the serial number revealed it was made in 2002. I condemned the water heater straightaway and told the homeowner this needs to be replaced with a direct vent model. So why do people cut corners with these? The answer is money; a direct vent water heater for a mobile home costs twice as much as a natural vent. If this were to cause a fire, your homeowners insurance company may refuse to pay your claim.

This is another shot of that furnace vent in the 80 year old woman's home. Again, no flex liner and there was no inspection sticker on the equipment, which was the case with all of these. The inspector would have failed all three of these straightway. In the case of the 80 year old woman, I noted her belligerence as well as the venting methods and a leaking dielectric union on the water heater I fixed. In the case of the mismatched venting, I noted and suggested to the customer to get this fixed soon. She was grateful and appreciative, which made my day. Again, if you want to do this for yourself or a friend, at least take the time and spend the few dollars to do it right. I would at least pull a homeowners permit if this is allowed in your area, but a licensed contractor SHOULD pull a mechanical permit. Every one of these venting situations is an accident waiting to happen. Maranatha!

Saturday, January 11, 2014

GMC Envoy 4.2L Alternator Replacement.

I imagine if you have a Saab 9-7x, 2nd generation Olds Bravada, Chevy Trailblazer, Izuzu Ascender, or Buick Rainier with the Atlas 4.2 liter I6, this procedure will be the same. As always, with any car repair work, there is a risk of injury, death or property damage. Use common sense when working on any electrical or moving part and implement any and all safety gear or procedures at your disposal. Tie back long hair and secure loose clothing. Wear gloves and other protection to prevent cuts and scrapes on sharp parts. The fan and clutch are expensive if they break as a result of mishandling. The wire harness to the fan clutch is particularly vulnerable to being caught in the fan and broken, wrecking some very pricey parts. Use extreme care and do this and any other repairs at your own risk.
The GMC Envoy is a body on frame panel truck that seats five to seven people, and the XUV version sports a retractable roof and a mid gate along with a weird looking behind. These are available in two or four wheel drive which is much more common. The version we're working on today is a Four wheel drive, 2003 Envoy SLE with the garden variety body that seats five. It has about 166,000 miles as of this writing. It also has the Atlas 4.2L I-6, which also more common than the 5.3 liter V-8. My dad replaced the battery a few days ago because it was over four years old and died in the extreme cold this past week. The engine sputtered and stalled when the heater was switched on. I found the voltage to the battery with the engine on varied from zero to fourteen and a half volts, and despite an "ok" from AutoZone, it was time to replace the alternator. They admitted they couldn't test the voltage regulator, even though the same was installed inside the part. Thanks, NOT!
To replace this part, you'll need an hour to do this job. You'll need a serpentine belt tool, a ten and fifteen millimeter wrench and sockets with a breaker bar and socket wrench. You can also hook wrenches together to get more leverage, but a breaker bar will be better. A socket wrench will be mandatory to get the alternator bolts out of the alternator boss as these are extremely long.

The mount above the alternator has 4 bolts, with the fourth
underneath the mount screwed to the engine. This is the space you
have to get the alternator out.

 
Remove the belt from the alternator and if it's sketchy, now is the time to replace it. The guide for threading it is molded on the fan shroud. IF you're saving the belt, take the loop off the alternator pulley only. The next thing to do is remove the NEGATIVE battery cable. The upper mount pictured above needs to come off and the fifteen mm bolts will be a PITA to remove. Use a breaker bar to get the two front ones and underneath the mount off. The ten mm bolt just needs an ordinary socket.
There are three fifteen mm bolts holding the alternator directly to the engine; two are on top and one on the bottom. If you're careful, you can use a socket wrench to get these out without breaking the plastic fan. Just let the fan move freely as you carefully swing the wrench back and forth. Loosen all the bolt, then remove the bottom first and the top ones last. Unclip the voltage regular connector and remove the wire from the battery terminal with a ten mm wrench. Carefully wiggle the alternator out between the fan, shroud and air conditioning hoses. This part is big and heavy, so taking your time is critical. You can also remove the intake plenum, help on by two clamps and two ten mm bolts, and move the wire harness out of the way to help out. However, this will only get you a minimum of clearance. You could also remove the fan and shroud, but this will add an hour to the job.

I would suggest making sure the battery is fully charged before putting the new alternator in service as this is not designed to change the battery per se. The alternator provides electricity to run the accessories, including the heater, seat warmers and other technical wizardry as needed while topping off the battery. It is not designed to charge the battery on a modern vehicle. You need to disconnect the battery on BOTH SIDES to charge it or you may fry the electrical system. Installing the part is the reverse of removal, but make sure the belt is seated on the pulleys and the tensioner retracts and moves freely. Again, if this or the belt are sketchy, they need replacement. When you start your truck, the engine will idle weird for the first time. Take a look at your work and make sure the tensioner holds steady and doesn't bounce. Also run the heater, lights and other accessories; the idle should not change any appreciable amount, nor the charging gauge change a whole lot.
Road test your truck and you're done. Maranatha!

Why You Should Call a Pro.

Happy 2014 and sorry for the lack of posts, but if you live in the Northeastern United States you know what the situation is. We've had the double whammy of power failures AND double digit lows without even factoring in wind chills. This means furnaces have been working overtime and if something is going to fail, it will. The result is that I've worked 60+ hours this week and the past several weeks getting these furnaces to rights. As a side note, if you have a Lennox Whisper Heat, or any Lennox product with the Dura Curve heat exchanger, get it inspected as soon as possible. You may have a health hazard at best and a death trap at the worst. These furnaces start with the model numbers G8, G12, G16, and G20 and were made from the 1970's (to the extent of my knowledge) to the late 1990's. I use an infrared camera to inspect these, but taking the duct off the top and using a mirror can also suffice, unless it's a counterflow model. Since I got this camera, every furnace with these heat exchangers I've scoped has had a failure; EVERY ONE OF THEM! Even if yours hasn't failed yet, it will! Of course this is the same deal with the Lennox G14, and G21 (Pulse) models. These are very efficient for their time, with 97% not unheard of, but these furnaces are over 20 to 30 years old. When these fail, it will be difficult to start and you will left with a no heat. Best to either test the heat exchangers every few years or just get rid of them. Nothing against Lennox because they made a good product (although parts are expensive and the present models are over engineered) but this is what I've been seeing folks. As you will soon learn, if you haven't from me already, all manufacturers make a few mistakes. I've had issues with every brand across the board, and some more than others.

Counterflow Lennox Whisper Heat with Inspector Infrared Camera.

One brand I've been seeing more and more of are the Nordyne family. Tappan, Gibson, Frigidaire, Thermal Zone, and Miller have had their share of issues. In the case of a two year old Gibson, I had to remove the control board to clean the flame rod; not a good design here folks. You shouldn't have to remove anything other than the flame sensor to clean or replace it. This is double for the igniter. On the 90% models, the drain fittings to the vents always break, but these aside, with proper installation and care, they'll last you a good ten to fifteen years.
One trait of these furnaces is the fact that many can and will buy them without a license or pulling a permit. Instead of doing a proper load calculation, which is measuring the square footage, windows, and ductwork to properly size the equipment, they'll look at the BTU ratings of the old furnace and buy a new one with the same ratings. This is not the proper way of doing things, but I digress. Another is that these same people will try and play Mr. Fix It; installing used, substandard or the wrong parts. I was in a home that was hacked, and not in a good way. This was the way to get to the basement, and yes, this was a shed roof made of OSB about 2 feet over an open stairwell.



 

The stairwell was pretty hacked too.
 

 
The furnace was even worse :(
Sorry for the blurry pic!
 
This is the way they jury rigged the drain fitting
that broke off.


To make a long story short, I found this furnace with a blown board, a worn vent motor and a jury rigged drain fitting. The customer replaced the igniter, which touched the frame and shorted out the board the minute it fired up. I installed a Glowfly, re-replaced the board, the inducer, and installed a proper drain fitting. It took me three hours because I had to get another board, replace the igniter, plus grill them about the mess they made so I had a clue as to fix the damn thing. I gently reminded them that since you have an appliance service plan or ASP, call and I'll be happy to fix the furnace. It cost almost $1200 to fix this mess by the time I factored in two boards, the inducer, the igniter, and the drain fitting with pipe. If the customer had called when the igniter quit, the cost would have been less than $500, but because he elected to take this upon himself, he made an additional $700 of work for me to do. The moral of the story is that you can be handy all you want, but there are some special skills that are required when trying to fix anything electrical. I have many years of training, and thousands of dollars of tools that require updating and replenishment regularly. My multimeter alone costs $200 and the camera I use for the heat exchanger is close to $3000. Most importantly, I've been doing this on and off for nearly 28 years. This is why I add those disclaimers and implore you to use caution in your work. Maranatha!