Question about Superior Lennox Blower Thermal Sensor - BTS

2 Answers

Very loud induced draft furnace

I have a 20 year old Lennox Pulse. It started to make an odd noise so I removed the panel over top of the induced draft motor while it was running. (I out it back on, tightly, of course) Now the motor growls at freakishly high volume. I had a repair guy in and he thinks its fine.

I just can't believe that it goes from not sounding like a lawn mower to sounding like a lawn mower and there's nothing I can do about it.

Posted by on

  • engineer09 Feb 27, 2009

    We have a new Lennox G43UF36B-70 70,000 btu input furnace (92% eff.) installed June 2008 in Columbus, Ohio area. During the heating season, the induced draft motor, when it starts up and continues to run during a heat cycle, creates a low frequency vibration. This can be heard at the furnace location (basement) and in rooms upstairs (single floor home). It is annoying, and after that motor shuts off, the furnace continues to run acceptably quiet. If the refrigerator in the kitchen also is running while the induce draft motor runs, there is a beat frequency vibration that you can hear being generated. That goes away when the induced draft motor shuts off.

    The dealer/installer has replaced the motor twice with a Lennox sent replacement, but it continues to be the same problem. The dealer cannot come up with an answer. I don't think this should be characteristic of the furnace operation.

    I have not seen this problem with another energy efficient furnace installed at another home. It is a Goodman GKS90703BX that has about the same size induced draft motor and exhaust vent piping connection as our Lennox. The furnace is very quiet even when the induced draft motor is running, and no noticeable vibration at the furnace or in other rooms.

    Before our warranty is up, I would like to know if there is a way to know if this is a faulty furnace, or just what causes the Lennox to operate this way. Should I insist that Lennox (or the dealer) show me another home installation of this same furnace to see if it is the same or similar problem?

    Thanks for any suggestions.


2 Answers

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

If it's a pulse furnace most were built with what's called a flapper valve and it is in need of replacement. If 20 years old it also needs to be checked for heat exchanger damage. This will need to be done by trained HVAC tech. There is no way to see inside exchanger on this system and needs to be done on table testing. This furnace at one time had a problem with heat exchangers and Lennox subcontracted this out to a company that did the liners wrong. Customers had no way of knowing there was a split in the heat exchanger until it was too late. And yes there was a warrning sent out to all people who owned one to have it checked. I CAN'T even remember the last time I saw a pulse furnace after that. I've been in the HVAC field for 30 years now. Hope this helped you.

Posted on Nov 27, 2012

  • Level 1:

    An expert who has achieved level 1.


    An expert that gotĀ 5 achievements.


    An expert whose answer gotĀ voted for 20 times.


    An expert who has answered 20 questions.

  • Contributor
  • 27 Answers

When you tighted it it very well could have done damage to the motor or you could have it off kilter 1 of the 2

Posted on Feb 06, 2009

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Need to find a replacement part

Here you go Angela

1149097 Draft Inducer Assembly - AllParts Heating
  1. Cached
  2. Similar
Draft Inducer. 1149097 draft inducer for Heil, Tempstar, Arcoaire, Whirlpool & Comfortmaker brand model furnaces. This part replaces old part number 1008416.

Arcoaire Furnace Motor Parts: Fast Shipping
  1. Cached
  2. Similar
Furnace draft inducer assembly. The draft inducer motor draws air into the burner and exhausts it out the flue. If the draft inducer motor is defective, the furnace ...

Arcoaire Furnace Parts: Fast Shipping
  1. Cached
Furnace draft inducer assembly. The draft inducer motor draws air into the burner and exhausts it out the flue. If the draft inducer motor is defective, the furnace ...

Direct Factory Replacement Inducer Blower Motor Used in 90 ... > ... > Oem Direct Replacement Models > Arco Aire
  1. Cached
  2. Similar
Direct Factory Replacement Inducer Blower Motor Used in 90% Furnaces. ... Comfortmaker, Intercity Products Snyder-General, Heil, Tempstar, Arcoaire Draft Inducer Blower Motor. ... Used in ICP Equipment Models: ... GUH125A016CIN

1149097 - Arcoaire Furnace Draft Inducer / Exhaust Vent Venter Motor ...
  1. Cached
1149097 - Arcoaire Furnace Draft Inducer / Exhaust Vent Venter Motor - Fasco Replacement: Replacement Household Furnace Motors: Industrial ... Draft inducer motor for arcoaire model guh125a016cin Google Search

Nov 27, 2016 | Heating & Cooling

2 Answers

I removed my Fasco 7021-11577S when the bearings went bad and ordered the A225 OEM replacement. I notice that when mounted this new draft inducer it whistles really loud .Is the hole in the back of the...

There should be a gasket between the mounting flange of the inducer motor and the furnace. If you do not have that you can use a small bead of blue or red silicone caulking to seal it. Hope this helps you. Thanks

Mar 29, 2011 | York Furnace Draft Inducer Blower Fasco #...

1 Answer

Lennox pulse 21 furnace - nothing runs on but control board tries

you will need to verify voltage from the board to the inducer. If you have the installtion manual there is a flow chart for the sequence of operation of the furnace.
The basic sequence is:
1. thermostat calls for heat
2. inducer motor starts and runs for a pre-set amount of time
3. the pressure switch closes and allows for ignition trial
4. ignition is proved back to the board allowing the system to operate.

Verify 120VAC to the inducer motor upon call for heat from stat, if you have 120 at the leads that connect to the inducer and it does not start , the motor is faulty. If the inducer starts use a voltmeter across the pressure switch terminals, a voltage reading of 0 VAC will verify contact closure and ignition should occur.

The pulse furnace was under a factory recall due to breaches in the heat exchanger, unfortunately for you, the Lennox Corp. has ended the program that allowed for an allowance / furnace for replacement. To test the heat exchanger a special kit is required from lennox that will verify integrity of the heat exchanger. (If the heat exchanger seal has been comrimised the pressure switch will not prove and the igniton sequence will be interupted and cause the system to go into "lock-out" mode).I know this is probably not what you wanted to hear. Hope this helps, please list as "very helpful" if it did

May 08, 2010 | Heating & Cooling

1 Answer

When the furnace comes on after recovering from low thermostat setting, we can hear a loud noise, something akin to a wooden bead that's being blown around inside the unit. Once temperature is reached, the...

Could be correct, or you may have something in your fan that either fell into or crawled into your fan through the exahust duct.Since you have a service contract, have they actually been out to look at it or did they tell you that on the phone. It might be worth removing the fan and clear any forign matter. The problem is the labor to do that would be the same as to replace it. What does your service contract cover??

Feb 24, 2010 | Omega Trane Furnace Draft Inducer Blower...

2 Answers

The fan motor went out and the furnace is not even 5 years old.

I have an Amana High Efficiency furnace that I purchased 5 years ago this past October (2009). My furnace started making a horrible noise last night and then stopped working. The repair person, told me my draft inducer motor needed replaced, and showed me where the plastic fan blade inside of the inducer was "chewed up." Of course my first question is, "How can a 5 year old furnace need such a costly repair already?" The only answer I received is that it will cost me close to $500.00 to have the situation remedied (service call, parts, labor). I started looking around on the internet today, and discovered that high efficiency furnace inducer motors are usually encased in plastic and the motor fan blades are made of plastic rather than metal like the lower efficiency models. Turns out that these plastic blades over time can't withstand the high heat generated and in time (they estimate 3-4 years) break. The damage to the blades causes an imbalance in the way they spin, which in turn, generates the resulting problem of a damaged draft inducer motor. Appears this is a design flaw. Yeah! I'll say. I spent $3100.00 for a brand new furnace and 5 years later I'm paying another $500.00 and apparently can look forward to doing the same in 3-5 more years! Maybe this answers in part your question?

Dec 07, 2009 | Goodman Furnace Draft Inducer Blower ...

2 Answers

I have a Lennox Pulse furnace. It's making a

The bearings are bad. You need to replace the motor. Motor cost $75 to $125. Labor is on avg. $150 to $400 with an decent A/C Company . You can try to oil it but its not recommend by Lennox. That furnace at the time they build it was top of the line. Good Luck.

Oct 14, 2009 | Heating & Cooling

1 Answer

Noisy Amana furnace

Remove the flue pipe from the top of the induced draft motor. Check to see if there any obstructions in it. If so remove them. If not replace the motor assembly.

Jan 02, 2009 | Honeywell Power Humidifier: Furnace...

Not finding what you are looking for?
Computers & Internet Logo

669 people viewed this question

Ask a Question

Usually answered in minutes!

Top Superior Computers & Internet Experts

Brandon Berry
Brandon Berry

Level 2 Expert

407 Answers


Level 1 Expert

16 Answers

Milton Scott

Level 1 Expert

23 Answers

Are you a Superior Computer and Internet Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides