I just did a heat exchanger on exact unit. The one I did was from 2013. It only took me about 2 hours to replace once on site. They actually have a 20 year limited warranty
I just found/diagnosed a failed Secondary for a carrier furnace. Customer called us out because she smelt Bad eggs/fish when the furnace would run and thought it was a dead animal. I learned from watching you that I need to look at the Heat Exchanger because you mentioned that
😳 a local manufacturer here in Aus had a older model gas furnace that would notoriously suffer corrosion around the pressure switch tube that went down into the “sealed” heat exchanger… the negative pressure from the blower would then pull combustion gases straight into the supply ducting… Terrifying stuff, a customer of mine recently had one of these units
That style unit is one of the worst as far as heat exchanger failures. I’ve changed a many of them. You will have to reuse the faceplate when changing the heat exchanger. Also be prepared for some screw heads being corroded.
I usually find the cracks on those "Lennox" units within about the first 6" up top were the flames go into the heat exchanger. They were pretty notorious for getting those big oval hot spots on the side walls. And the crack would usually be right in the middle of the hot spot. And usually on either the far right tube or the far left tube 😎👍 Maybe the tsunami caused that unit to roll out! 😮💦💦💦💦💦
Pretty short life, but I know living outside a package unit takes a real beating. I see a newer ECM in that blower, way too clean to be original. Inducer bearings getting noisy, in addition to the bad heat exchanger. That AirEase ain’t so easy on the customers wallet. Another enjoyable video.
Every one of those Lennox style package units I’ve touched seems like it has a bad heat exchanger. Especially In those little divets along the sides of the individual cells. If they not already rusted through, you can usually poke right through them with your bare finger
If you have to replace heat exchanger on package unit then always order the face plate with it as good practice. On occasion, replacing the heat exchanger without the face plate will not be possible because some of them are deteriorated beyond yiability. I have changed thousands of heat exchangers, particularly ICP/CARRIER among others Some were as old as 30 yr old but h o simply refuse to replace system.
Went to a call yesterday where the blower came on at the same time as inducer. It turned out home owner installed a nest thermostat in the summer time, and it was programmed for heat pump.
I have 2 air ease 2 ton gas pack units that I installed myself 15 years ago. I use natural gas from my own gas well. Both units have developed holes in the heat exchanger. In the past I had to change both draft inducer motors and repair the wiring in one gas valve because the crazy little pressure contacts broke off. I wired around them. The holes in the heat exchanger are caused by rust in the dimples of the exchangers. I have replaced one of them with a mr cool unit but only used heat so far as it has been so cold. If this mrcool unit proves satisfactory, I will purchase another identical unit as it takes a unit on both ends of my house. I have sensors in all rooms that detect natural gas and monoxide and the system will turn of all gas coming into the house. Hopefully these new units will be ok.
Hope your change out goes well lol sell them a good unit if not under warranty. we have a lot of problems on package change out with old duct and bad sizing here in southern Kentucky. What a shame your right
Even though I do not know what the original complaint was, since the draft inducer was running continuously, it was probably the gas valve. This is what happens because the valve is monitored by the control board. There are about 4 pressure contacts inside the gas valve and due to metal fatigue, they do not make good contact and even break off. You can wire around the contacts.
@@asintonic hot flue gas goes through that heat exchanger on the inside. Air from the home flows across the outside of it to pick up heat. The two should never mix, but rust makes it so. Then you've got combustion gas inside your home, potentially deadly. And yes the heat exchanger can be replaced, although it's sometimes more economical to replace the whole shebang.
The old click and dip. Yeah, if a rollout is tripped, spend some time inspecting everything. Once had a wasp nest inside a draft inducer that was causing the heat to light, but not induce enough draft leading to a backfire when some of the unburnt gas finally lit.
All outdoor package units condense in the HX. The reason is especially in humid climates, that inside of the HX is always exposed to outside air, it gets in thru the exhaust outlet. If the homeowner keeps the A/C cranked in the summer, so that the internal temp of the HX is well below the outdoor ambient dewpoint, you'd be surprised how much they can "sweat" inside. Coastal areas are even worse, that salt air mixed with water really trashes heat exchangers fast. Back in the 1980's me and my Dad would replace Carrier heat exchangers on a restaurant across the street from the beach, and it was just routine maintenance to replace the HX's on the two rooftop units every 3 years. The restaurant owner could not afford to keep buying new units every 3 years! So was much cheaper to just replace them on a schedule. Even stainless steel can corrode in that kind of environment. The only way to make something last would be to make a HX out of some kind of Cupro-Nickle alloy, but the huge problem with using that is they are very intolerant to repeated extreme thermal cycling and would crack in no time. And a cracked HX is just about as useless as a rusted out one, lol. I guess you could build one out of Inconel out of recycled jet engine turbine blades, but nobody's going to buy a $20,000 furnace, you could buy 7 Aire-Ease for that much. lmao.
#Question ... Nordyne/Miller CMF95 /072 Mobile Home Propane Gas Furnace, 4 years old. When the furnace is cooler & only running once every 3 hours or so, it takes 26 seconds from the "CLICK" of the Hot Surface Igniter to the "CLICK of the gas valve opening & flames coming on, BUT >when the furnace is running every 45 minutes during colder weather, there are only 8 seconds between the igniter "CLICK & the Gas valve "CLICK, would you consider that normal ? The furnace uses a Silicon Nitride type Igniter. I have OCD, so I am inclined to pay attention to this kind of stuff & have been counting the time between clicks for months now, I live in Mass. & noticed as I leave the furnace on full time, versus controlling the firings during the early Fall, it just fell to 8 seconds versus the 26 seconds, & if I turn the furnace off for a few hours, it goes back to the 26 seconds for the first burn. I would have thought the Control board would have a fixed time for such an operation, your opinion would be great. Thanks ... LOVE your videos
Got a question. I'm trying to help a friend. He has a unit that looks just like this one. I replaced a high limit switch. Due to it being all crusty. But there's flame roll out in one of the 3 cells. While it does run a short period of time. The new high limit shuts it all down. My question is why the God awful smell. Almost like a chemical smell. Almost like formaldehyde smell. Is that a clogged heat exchanger?
Yes! What you're smelling is actually acetaldehyde, a byproduct of incomplete combustion. It can have a sickeningly sweet kind of smell to it. Shut it down. You can get a replacement heat exchanger, they usually have a 20 year warranty on them. Even if not under warranty a lot of times they aren't very expensive. These Lennox/airease units I wouldn't though, they don't give you new screws and faceplates etc, and dealing with rusted off screws is a pain in the butt. Also, if you're going to replace the heat exchanger I wouldn't do it without new burners as well. The problem with those style of burners is they get rusty, and the crosslighters get clogged with rust; there's only a tiny slit that lets the flame jump from burner to burner. This can result in delayed ignition or ignition failure because the flame sensor is usually on the farthest burner from the ignitor.
There are a few things that could be wrong, take blower motor out and inspect heat exchanger, check all orfices and gas connections, if it’s a package unit then must be level on pad or condensation will not drain out the inlet of the heat exchanger. Depending on the age chances are the blower is blowing the flame back due to a hole. As the unit warms up the hole will become bigger. Must inspect operation and see what it’s doing if heat exchanger is still in tact. The list goes on, can’t diagnose without actually looking at it
Ahh thats nothing. Ive seen them literally with cracks on bends with rust around the whole thing. People push things till they have no choice but to replace it...
There should be very little to no CO in the house. The pressure from the blower motor on the external parts of the heat exchanger should be greater than the negative pressure inside the HX from the induced draft blower. As long as the induced draft motor is in good shape, which it was. The bigger issue is that rollout switch is going to keep tripping to the point it won't reset anymore, those little rollout manual reset high limits can only be tripped a few times, and then they're junk, they're very cheaply made. Bypassing the limit is a really bad idea, if there's enough rollout it could start a big fire in the unit, and burn up all the wiring etc. I saw one that that happened to 10 years ago, there was not much left of the circuit board, all the wires and transformer, and thermostat wires was charred, compressor contactor etc. This was a 2.5 ton Rheem package unit. I was able to get a new heat exchanger for it under warrranty, but they didn't cover replacing the contactors, wiring harness, 24v transformer, control board. It could have been a lot worse, but managed to save it. The only reason for saving it really, was the compressor had just been replaced the prior year, and the A/C side of things was working very well. If it didn't have a new compressor and indoor blower motor in it already, then it would not have been worth repairing at all.
