What other furnace brands should I consider? - Canadian TV, Computing and Home Theatre Forums
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post #1 of 14 (permalink) Old 2020-02-05, 10:41 AM Thread Starter
Join Date: Mar 2006
Location: Port Stanley, ON
Posts: 627
What other furnace brands should I consider?

Well, at 8 months outside the 10 year warranty, our Lennox G71MPP 036 - 070 is done.

Contractor came in this morning and discovered the heat exchanger is shot. High CO readings in the house.

In the 10 years we've owned this furnace, the main board, combustion air fan, 24 volt transformer, condensate drain trap were all replaced under warranty.

This is the 3rd Lennox furnace that has failed in 38 years.

Can anyone suggest a furnace brand with some long term reliability? Heat loss study on dwelling shows total BTU heating demand at 40,000 Btu's.

Ironically, we were entertaining going to geothermal this year and are still looking into financial incentives for that.

The contractor has located a replacement heat exchanger for our furnace and it will be replaced in the morning. Don't know the labor costs, but expect it to be around $750.

Thoughts? Suggestions please.

Delhi SFA 1483, Antennacraft Suburban VHF, CM7778

Last edited by 57; 2020-02-05 at 11:13 AM. Reason: Added "Furnace" to title
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post #2 of 14 (permalink) Old 2020-02-05, 12:55 PM Thread Starter
Join Date: Mar 2006
Location: Port Stanley, ON
Posts: 627
It gets better

So my heating contractor calls me back after sourcing a heat exchanger and cannot apologize enough and he says he has more bad news.

It now seems that my furnace is "carboned up" and as such I need to replace,

1. All vent piping.
2. Combustion air fan.
3. Gas valve.

Etc., etc. Total cost to repair this furnace has now all of a sudden ballooned to $2K plus. Why did he not tell us this when he was on site??

Obviously I'm being sold down the river. Another dealer has been contacted to come in to resolve the situation.
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Delhi SFA 1483, Antennacraft Suburban VHF, CM7778
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post #3 of 14 (permalink) Old 2020-02-05, 02:30 PM
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I am interested to know what you'll do at the end but can't you just buy a new furnace for like 2k plus installation?

My furnace is Lennox as well and it's old, like really old, probably 32 years old (original). I called around for maintenance and "Canadian Choice Home Services" gave a me a price for about 5k with finance options. I'm not going to change it until it dies out but will be shopping around to get a better price.

Canadian Choice Home Services told me I'll be saving 30-40% monthly on my gas bill which I don't believe. After doing some research, it looks like 15% saving on new furnaces.

Also, look into that 25% Ontario Energy rebate if you're planning to buy a new unit.
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post #4 of 14 (permalink) Old 2020-02-05, 04:45 PM
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The savings come down to a bunch of factors.

Depending on what type of furnace you had prior. A single stage, vs a dual/tri/multi stage.
A single stage will come on full black, so say 100% input of gas.. and heat up and blow till the temp is reached.
A multi stage, starts at a lower setting (say 30%) for a period of time, and if its reached temp, then stop, if not, ramp up to the next % level). I think these ones can take a little longer to heat, but could reach the heating up target temp with using less gas.
(assuming that your not going from like ice cold.. just a normal few degree change)

And then everything else going on in the house as well.
How good the insulation is in the walls, the attic, etc. The seal on the windows/doors, etc.
Anything that bleeds heat.. the furnace will run more too

We had an old 20ish year old when we moved into our current house. It died within 6 months of moving in. The newer multi stage, we save somewhere between 20-25% difference on the gas bill from when we moved in. (but we also upgraded from the builders crap windows to brand new ones, etc at the time too)

Rogers Ignite Xi6, LG 47LV5400 LED TV, Yamaha
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post #5 of 14 (permalink) Old 2020-02-05, 08:00 PM Thread Starter
Join Date: Mar 2006
Location: Port Stanley, ON
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Originally Posted by liverpool View Post
I am interested to know what you'll do at the end but can't you just buy a new furnace for like 2k plus installation?
I can purchase a tier 2 single stage furnace installed for around $2500, but my gas consumption would be much higher.

When our Lennox G71 was installed in the fall of 2009, it cost us just under $5K taxes in. Due to it's design (full modulating) our heating costs have been low. But keep in mind our house is 1100 square feet in size and when constructed it was built to the R2000 standard. The major complaint I had about this furnace was that our basement was always cold after it was installed. With the furnace running on "low fire" most of the time, we never got the CFM's needed to properly heat the basement.

We owned a house in London ON that had an Olsen furnace manufactured in Tilbury ON (now defunct) and that furnace lasted 38 years before the heat exchanger went. The only thing I replaced on that furnace was the thermocouple which cost less than $20. Granted it was only 60 percent efficient, but hey, it cost us nil in repairs.

Oh how I long for days past.

Delhi SFA 1483, Antennacraft Suburban VHF, CM7778
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post #6 of 14 (permalink) Old 2020-02-05, 08:18 PM Thread Starter
Join Date: Mar 2006
Location: Port Stanley, ON
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I reached out to another Lennox dealer for a second opinion. Here's the verdict.

Another tech came to the house to assess the situation. He discovered the inside back of the heat exchanger was heavily sooted. The combustion air fan has a fair amount of soot and the pressure switches are likely fouled too.

So......we are getting a replacement heat exchanger at no charge but must pay labor costs, fair enough. We've also agreed that we should change out the combustion air fan and pressure switches.

What none of us know yet is the health of the modulating gas valve. The tech said he's never had to replace one yet, but hey, who knows?

I'll chime in next week on my adventures.

Have a good weekend all.

Delhi SFA 1483, Antennacraft Suburban VHF, CM7778
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post #7 of 14 (permalink) Old 2020-02-08, 08:34 PM
Join Date: Jun 2016
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To have soot buildup, you have to have a very serious combustion problem.

It's more likely to happen on propane vs gas, especially if the conversion was not done properly.

Are you on propane?

To have a heat exchanger failure at this point, either it was over-fired or underfired, had poor airflow or another problem.

If you fix it, find someone who is committed to doing a combustion analysis and check gas pressure, temperature rise and clock the meter. (only natural gas has meter to clock) After repair, very important to make sure it's working properly or the next heat exchanger will soot up.

Your problems with this unit are not caused by the furnace being lennox. Any brand will have major issues if the combustion is really off and or ducts undersized.

Lennox has released some really good furnaces as well as junk - the same goes for a lot of other brands. It's best to avoid brand new designs and the G71 was their first modulator. I'm sure they've worked the bugs out by now.

Nothing you buy now will be super-reliable long term. After 10 years, expect to replace some parts; after 15 to 25 years, the entire unit.

The really old stuff lasted 30 to 40 years. The metal is thinner these days to get the efficiency and they're loaded with parts from third world countries.

Repair vs replace:

Sorry to say, a modulator has super expensive parts -> the inducer is variable speed, you have a $1000+ ($500 for the module if motor is still okay but module failed) blower motor on top of that.

If it was me, I would compare the cost of labour with getting a simpler furnace installed. I'm normally for repair, but you could pay $700-$900 now and then another $1000 on parts later for a aging furnace, coming close to half the cost of a new one to get another 5 to 10 years.

A 40 or 44k (lennox/armstrong make the 44k) 2-stage with a fully variable speed or if u want lower repair costs, a x13 (marketed as multi-speed) motor would provide similar comfort to a larger modulator at a lower cost of ownership.

I think 2-stage is the sweet spot when it comes to weighing comfort against repair and purchase costs.

A 44k 2-stage goes down to 28k, a 66k G71 drops down to 25k btu/hr -> not a big difference.

You may miss is very fast warmups though. (the 66k is too large for a house with a 40k heat loss!)

If a 40k 95%+ with 38k output is a little boarder-line and you don't want another lennox product, you can get a 42k rheem.

Just be sure your calculations were done accurately. Using existing gas bills can be unreliable -> it's better to time cycles on high or do a load calculation. If it turns out you actually have a 50k heat loss and you get a 38 to 42k btu out furnace, you'll be very sorry when it hits -25c.

Last edited by user_; 2020-02-08 at 09:14 PM.
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post #8 of 14 (permalink) Old 2020-02-08, 09:42 PM Thread Starter
Join Date: Mar 2006
Location: Port Stanley, ON
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Thanks user_

Another HVAC company came to our rescue on Wednesday. Early Thursday morning I rec'd a phone call from the service manager informing me the replacement parts arrived and they would be at our home around noon.

Here is what needed replacement:
Heat Exchanger (lifetime warranty replacement. $2500 cost for the heat exchanger if you had to buy it) We only paid labor to replace this (4 hours).
Combustion inducer fan
2 pressure switches.

Total cost $1577. Far cry from the original quote.

The reason for the soot was the cracked heat exchanger. CO levels at the exhaust prior to repairs were in the 1700 ppm level. After the repairs, CO levels 17 ppms low fire, 15 ppms high fire. So the cracked heat exchanger resulted in the soot build up. Gas valve checked out okay.

The original dealer wanted $4K - 5K for a new furnace install which I said "NO" as I don't want to fork out $5K every 11 years for a furnace. That's obscene!

One might be better off to just install a Bryant or Goodman, etc. as there is no long term reliability in these things anymore. Save your money.

One final note:
The plan is to go geothermal in 5 years or less as significant advancements have been made in geothermal which drastically reduce the cost.

Delhi SFA 1483, Antennacraft Suburban VHF, CM7778
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post #9 of 14 (permalink) Old 2020-02-08, 11:07 PM
Join Date: Jun 2016
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A cracked heat exchanger normally won't cause sooting unless really, really bad, depriving the burners of oxygen in which case the pressure switches should not close and rollout in extreme case would have tripped.

Cracks allow extra air to leak into the heat exchanger, they don't always cause high monoxide production.

It can take flame impingement on metal to get soot production. Burners may have been replaced with heat exchanger, correcting problem.

It's completely abnormal to lose a heat exchanger on a 10 year old unit - it takes overheating, overfiring, flame misalignment to do it.

They don't crack in 10 years unless abused or there's a very severe flaw in the design.

This is not a "lennox problem".

Bryant BTW had tons of problems with their secondary heat exchangers - that has since been resolved. No brand is immune. I don't recommend getting a bryant/carrier due to parts costs and some other things i won't get into here.

Carrier/bryant is in the same league as lennox, trane, etc.

Electricity is far too expensive to do geothermal in ontario if you have gas available.

Last edited by user_; 2020-02-09 at 01:51 AM.
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post #10 of 14 (permalink) Old 2020-02-15, 06:50 PM
Join Date: Oct 2008
Location: S.W. Ontario
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I may as well chime in. In 2004 my insurance company informed me my oil furnace and tank would have to be re-certified because it was over 25 years old. Extremely expensive. So I switched to gas, which had recently been installed in my subdivision. I got a few quotes and a local contractor gave me a good deal on a new furnace and removal of the oil tank. The furnace was a Weather King, which I'd never heard of, but turned out to be a Rheem high efficiency. I have a maintenance contract with Reliance and in the 15 years I've had it only a few little things needed service, nothing major. When I asked the tech about the brand, he said they were very reliable.
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post #11 of 14 (permalink) Old 2020-02-23, 10:26 PM
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^Rheem is good stuff but i don't like the company because they manufacture nearly everything in mexico.
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post #12 of 14 (permalink) Old 2020-02-24, 10:25 AM
Join Date: Oct 2008
Location: S.W. Ontario
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Mine was made in Arkansas.
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post #13 of 14 (permalink) Old 2020-02-24, 09:32 PM Thread Starter
Join Date: Mar 2006
Location: Port Stanley, ON
Posts: 627
Well, it turns out my Icomfort board now has issues. Furnace is generating persistent E273 errors (loss of flame sense on low fire) which the contractor has isolated to the Icomfort board.

This will be the third board installed in this furnace in 11 years.

Tell me again user_ how this is not a "lennox problem"?

Delhi SFA 1483, Antennacraft Suburban VHF, CM7778
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post #14 of 14 (permalink) Old Today, 10:33 PM
Join Date: Jun 2016
Posts: 90
Did your contractor check the flame sensor current or just assume it's the board?

Is the problem intermittent or can it be reproduced each cycle?

You may have a not so good ground, dirty burner face, bad connection, etc.

If flame signal may be marginal it may drop slightly when on low fire, enough to throw a flame sensor error.

To go through 3 boards, either something external (power quality?) is killing them or it's been misdiagnosed and re-seating the connections when changing the board each time solved the problem.

If the boards were all junk there probably would have been a product bulletin or something by now. The g71 is not new.

The installation and maintenance has more to do with lifespan than the manufacturer. The control boards for all furnaces are only made by like 2 to 4 major companies. The boards are not made in house by lennox.

A furnace is not like a self contained plug-in appliance -> it needs to be properly sized, installed, setup/commissioned and maintained.
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