HVAC

Have HVAC Questions? Ask an HVAC Expert for Answers

Ask an Expert,
Get an Answer ASAP!

HVAC

Gas Furnace TUE060A936K Blower does not stop after gas

Customer Question
Gas Furnace TUE060A936K Blower does not...
Gas Furnace TUE060A936K
Blower does not stop long after gas burning stopped. How to troubleshoot the problem?
Submitted: 1 year ago.Category: HVAC
Show More
Show Less
Ask Your Own HVAC Question
Answered in 5 minutes by:
12/28/2015
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago
Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8,824
Experience: Retired HVAC/ Electrical & Boiler contractor. Industrial
Verified

Hello,

Make sure that the thermostat fan switch is not set to 'fan ON'... if it is set to Fan Auto then the problem is in fan relay mounted in the printed circuit card most likely.

Next please attach a well focused, close up photo of the wiring diagram glued inside the service panel, the picture needs tobe taken from straight on, in very good light.

You can use the paper clip- icon at the right end of the tool bar at the top of this dialog box to attach it here.,Include a picture of the thermostat wire connections to the printed circuit board in the same area.

If you have an error code showing, tell me what the code read out is on the wiring diagram or a sticker next to the diagram please.

If there is no paper clip-icon, look for the '+attach files' link at left of your send button.

I can mark it up with trouble shooting instructions.

We can go from there.

Ask Your Own HVAC Question
Customer reply replied 1 year ago
Hello Phil,
Attached are Wiring and Schematic diagrams of my furnace and Error Code Flashes. It's 15 years old. Recently I replaced a Gas Valve, but now have a problem with the Blower (its motor was replaced in May of this year). I turned off the furnace right now (after the Blower ran about an hour following gas burning stop). When I turned it on to see the status flashes, first they flashed fast (Normal call for Heat) but then the Blower started and after unsuccessful Ignitor light up, flashing changed to 4 Flashes (Open High Limit Device).
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

Hello again

http://screencast.com/t/GQVB16F4U

The printed circuit board has a black plastic fan relay on it, with its contacts welded closed if

it removing the red wire from the 24volt side of the transformer results in the fan still running.

Thanks for letting me work with you. When we are finished,if my answer has been polite, professional, and thorough,please locate the 'rate your expert button' and click one of the ratings .If you still need help let me know!.

Rating will not increase your charges, nor close the question, but is how I earn my living.

Thanks again.

Ask Your Own HVAC Question
Customer reply replied 1 year ago
English is not my native language and for me it's easier to communicate in writing.I've just removed the red wire from the transformer and the Blower did not start running upon turning furnace On. But when I put the red wire back and turned the furnace On it started to work properly: the induced draft blower came up, ignitor lighted up, gas flowed and got burned. About half minute later the indoor blower started.
I turned off the furnace and waiting for instructions from you on how to continue troubleshooting.
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

Hello again, if the furnace now works and the blower does not stay on all the time, then by disconnecting the red wire you may have solved the problem with the electronics. It will be best to wait and see at this point.

If the blower continues to stay on all the time, then replace the printed circuit card that I marked with a big red box.

http://www.furnacepartsource.com

Call them on the phone, all they need is the furnace brand and model number in order to get you a new printed circuit card.

Note: I am attempting to learn spanish, and its been difficult , your written english is perfect, no small feat to say the least, pronunciation just takes time and practice with a good voice coach.

Thanks for letting me work with you. When we are finished,if my answer has been polite, professional, and thorough,please locate the 'rate your expert button' and click one of the ratings .If you still need help let me know!.

Rating will not increase your charges, nor close the question, but is how I earn my living.

Thanks again.

Ask Your Own HVAC Question
Customer reply replied 1 year ago
Phil,
First you suggested to replace the circuit board if disconnecting the transformer wire would not stop the blower and now you're suggesting to replace the board after disconnecting caused the blower to stop running.
Why? What is wrong with the board? And how comes that disconnecting and then again connecting of the transfer wire could solve the problem with the electronics? And how is this problem associated with the "4 flashes" error code?
I don't want to replace the board and see the same problem. So please provide thorough explanations if you have them.
Thank you.
Alex
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

Hello again, so far i am not trying to fix anything, disconnecting the red wire from the transformer, disables the printed circuit card, and if the fan still runs with the power off to the printed circuit card that proves 100% conclusively that the relay contacts are physically burned (welded together).

That was the reason for that test.

However, if removing the red wire from the transformer resulted (accidentally) in a 'fix', that demonstrates an *electroinics anomally in the micro processor chip on the board, those electronics are sometimes influenced at least temporarily by a removal of power.

I will comment on some of the 'why's later, and to any extent that you wish.

Now.... this above ... is my statement after a measly 51 years in the business fixing these sorts of problems in HVAC systems of all types, from home style furnaces to multi million dollar systems seen in industry and tall buildings.

It does not mean by any stretch of anyones imagination that I know what on earth has gone on inside the atomic scale micro processor chip.... those are my *presumptions after experience with these since they came out in this industry beginning in the mid 1980's.

Here are some of the 'why's however.. The integrated circuit (the 'chip') is composed of electronics sub components, so small that hundreds of them can fit in a short strand of human hair... these are primarily transistors, capacitors, and resistors... the transistors function by changing state when power is applied to its base, or not applied to its base... there can be *residual charges* that do not abate as they should at times through the resistors and capacitors within the chip, holding the transistor in a switched position that was not intended by the designer.

Where do these charges come from? Only the shadow knows for sure, they can come from static charges introduced to the circuits from outside means, such as electrical surges on the incoming power, or from even touching the printed circuit card itself (there are lengthy articles on these issues if you would like me to provide links to them, or you can search them on google).

Click here for google search results on static electric discharge effects on integrated circuits

Diagnosis of these sorts of sometimes transient conditions is not worth the time and effort in a lab and is often not more conclusive than my abbreviated note above.

However, there can also be permanent effects, some of those mentioned in this series of articles, that occurs when a high voltage static charge causes an arc between circuits that destroys one of the 'wires' (only 6 or 8 atoms wide of gold, silver or sometimes copper)

Here are a few photo's.

You can click on any of the photo's that interest you, and get to the original web site. most often university or manufacturer web sites.

Here is a good book on the very broad topic of what causes these problems in the manufacturing process, and makes chips vulnerable to later damage post manufacture, (I spent 10 years involved in chip manufacturing facilities, for intel, IBM, and Texas instruments addressing this range of topic)

http://www.amazon.com/Dusty-Dirty-Plasmas-Noise-Laboratory/dp/1461357403/ref=sr_1_1?s=books&ie=UTF8&qid=1451370238&sr=1-1&keywords=micro+electronics+damage

Let me know if this addresses any of your questions on the topic and if not, what else you might be in question about.

We can go from there, without time limit,

Ask Your Own HVAC Question
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

When you have the information that you need and are happy with it, please rate my work, it is how I earn my living these days. Thanks

Ask Your Own HVAC Question
Customer reply replied 1 year ago
You wrote:
"However, if removing the red wire from the transformer resulted (accidentally) in a 'fix', that demonstrates an *electroinics anomally in the micro processor chip on the board, those electronics are sometimes influenced at least temporarily by a removal of power."
Why removal of power by disconnecting the red transformer wire might cause another result than turn off of the whole furnace?
Why with the blower running sometimes the ignitor would light up and sometimes would not with error code "4 flashes"?
Since yesterday night the furnace and blower worked properly but minutes ago I raised temperature on the thermostat. The furnace started but when the thermostat was satisfied and the furnace stopped burning gas, the indoor blower continued to run well beyond the fan-off period (fixed at 100 sec.). However it stopped in 100 sec. after I switched the thermostat off of heat.
Do you still believe that replacing the circuit board would solve the problem?
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

Hello again, if you had the time out of your busy to day to read that stack of references I left for you last time, you would know why you are getting these variable symptoms. Even then however only someone with microscopic x ray vision would know the real reason why.

We can do a heat stress test on the printed circuit card however.

Use a hair drier to slowly warm the printed circuit card up to120For a bit warmer, but not over 140F... if there is any change in the error codes or other furnace behavior... the card has a cracked micro circuit that opens and closes as the card expands and contracts... that proves a bad printed circuit card.

No change however does not prove the card is good however... but a change proves the card is definitely bad.

Let me know how that goes.

Ask Your Own HVAC Question
Customer reply replied 1 year ago
I see your point, but do not understand why you exclude the Thermal Limit Switch as the problem culprit. This switch should open at 260 F and close at 230. The error code "4 flashes" indicates that this switch is open. Why do you see the problem in the circuit board rather than in this switch? Or maybe the problem is with hot air output?
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

Hello again, it very well could be a bad high limit switch, it is just that in this case the most workable test sequence is the card first, then the high limit and a few other things,

Ask Your Own HVAC Question
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

The internet has been down in many aspects today, so I am sending this response in snippets to they do not get erased as i am typing.

Do the heat stress analysis on the printed circuit card, be sure you get to at least 120F, 130F would be better. If we get a change of any sort the printed circuit board is bad. It might also be true that the high limit is bad we can check that next.

Ask Your Own HVAC Question
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

To test the limit switch remove both wires from it next time the furnace goes off and sends an open limit switch error, use your multi meter to set on ohms to see if it is open (same read as holding both probes in the open air and not touching)

Ask Your Own HVAC Question
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

You can order a new limit switch or printed circuit card from

http://www.furnacepartsource.com

All they need is the furnace brand and model number as a rule,

Let me know how all that checks out, we can keep going without a time limit, hopefully the web will stay working well as it is right now.

Ask Your Own HVAC Question
Customer reply replied 1 year ago
it very well could be a bad high limit switch, it is just that in this case the most workable test sequence is the card first, then the high limit and a few other things"
What a few other things could be?
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

If you can just do the tests we can get to the bottom of the problem fast, if I spend too much time writing long missives about the business, that takes us off the fast track so to speak,

Other problems can be an oxidized pin in a molex connector. there are a few dozen of those, an intermittent polarity problem at the furnace power supply, electrical spikces caused by intermittent shorts any of the rotating components, blowers primarily,

and over a few hundred things that can go wrong with the printed circuit card electronics.

On this end it is possible for me to loose my train of thought if we skip around during a diagnosis, its best to stay on a linear path, that is generally quite fast and efficient, diversions obscure all that, and I can even forget where I was going. Here at our very reasonable rates it behoves me to be efficient.

I hope you can understand,

Ask Your Own HVAC Question
Customer reply replied 1 year ago
I tested the limit switch circuit, it's closed.
Are those molex connectors on the circuit board?
If there is an intermittent polarity problem at the furnace power supply, what should I replace?
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

Hello, testing various things at random takes days or at least many hours and is generally off on the wrong track, as was the test on the high limit switch... if you tested it with the wires removed from the limit switch ... did you do that? or did you test with the wires connected.

Let me know about that detail it is very important.

All of the white nylon connectors you see are molex connectors, there are many types, you can end up way way off into the tall weeds trying to test those with a meter, because just the act of testing them can correct the flaw... there are other approaches, that work way better.

We were on those paths earlier.

Let me know if you would like me to opt out so that you can work with other of our experts who might want to do this random testing approach.

We can go from there.

Ask Your Own HVAC Question
Customer reply replied 1 year ago
I don't suggest random testing, but I want a full diagnostic plan to nail the problem. So please readdress me to another expert. Thank you.
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago

There are printed full diagnostic plans for many furnaces..but not all furnaces... these are laid out in block diagram form.. and fill several pages, sometimes 6 or 8 pages, and each block will have several trouble shooting steps... it not only takes hours to go through all conceivable malfunctions... and that does not fit our rate or time budgets here, and in most cases it does not fit our customers instrumentation and skill sets.

Beyond that, such charts fail to check the 95% most common failures first, for a ludicrous example, the customer says their house was hit by lightning and a huge fire ball wiped out the TV and set fire to the refrigerator.... and now the furnace does not work.

In that case we can skip directly to a visual examination of the furnace printed circuit card, if that and the thermostat have been burnt to a crisp, in that case it would be ludicrous to do the 4 hour diagnostic block chart procedures.... procedures that our customers rarely if ever have the instruments or experience to execute.

Instead we ask 'how old is the furnace'... if the customer says its 20 years old, we know two things immediately, the furnace is at the end of its normal life span, and two, its not worth the $1,000 or more it will take to sort out how badly the rest of the furnace has been damaged.

I hope that helps, good luck with getting it repaired.

Ask Your Own HVAC Question
HVAC Technician: Phil, Mechanical Engineer replied 1 year ago
Ask Your Own HVAC Question
Ask Phil Your Own Question
Phil
Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8,824
8,824 Satisfied Customers
Experience: Retired HVAC/ Electrical & Boiler contractor. Industrial

Phil is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future.

JimmyBagley, IA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

Phil

Phil

Mechanical Engineer

8,824 satisfied customers

Retired HVAC/ Electrical & Boiler contractor. Industrial

Rick Mather

Rick Mather

HVAC Technician

3,133 satisfied customers

35 years experience, HVAC

Matthew

Matthew

HVAC Technician

2,014 satisfied customers

14 years experience in the HVAC field of service, installation, Manual J & D calculations

Kenton Guidry

Kenton Guidry

HVAC Technician

963 satisfied customers

12 years install/service experience.

Brian HVAC Guy

Brian HVAC Guy

HVAC Technician

953 satisfied customers

I have been an HVAC/R mechanic/technician for 30+ years.

Rick Ridley

Rick Ridley

UK Heating Engineer

871 satisfied customers

Retired But have had 30 years on the tools, Ex CORGI

Tom

Tom

HVAC Technician

770 satisfied customers

16+yrs HVAC/R service. Residential Commerical Industrial

< Previous | Next >

Related HVAC Questions
Having a problem with our fireplace... looking for some
HI, having a problem with our fireplace... looking for some assistance in troubleshooting … read more
Iohn Keffer
Iohn Keffer
HVAC Tech
Associate Degree
27 satisfied customers
I purchased a RTH2300B thermostat I have only 2 wires coming
I purchased a RTH2300B thermostat I have only 2 wires coming from old thermostat blue and white not sure how to connect . don't trust colors … read more
Billy
Billy
Journeyman Service Technician
State Licensed Mechanical Contractor
9,330 satisfied customers
Im having trouble switching my thermostat to heat i have a
Hi, Im having trouble switching my thermostat to heat i have a hunter thermostat model 44860 … read more
Gaztech
Gaztech
Technician
Vocational, Technical or Trade School
1,080 satisfied customers
I have a Payne furnace model #PG8MAA that seems to have lost
I have a Payne furnace model #PG8MAA that seems to have lost power. The blinking light is off, and auto pilot light does not light the pilot light. … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
Goodman two stage gas furnace, 3 years old, currently is
goodman two stage gas furnace, 3 years old, currently is code in system status code says LO , its firing up but not staying on? … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
Which symbol on the Friedrich heating/cooling unit is for
Which symbol on the Friedrich heating/cooling unit is for heat? Thank you! … read more
Airheatman
Airheatman
Heating & Air Conditioning Contractor
6 years college
1,836 satisfied customers
My boiler has E04 code but the reset wont work it apears
my boiler has E04 code but the reset wont work it apears that some water may have gotten to the display board … read more
Webb-Guy
Webb-Guy
tech.
73 satisfied customers
My furnace came on at 6:00 am when it was suppose to still
my furnace came on at 6:00 am when it was suppose to still be set at 62. Nothing I did could get it to shut off … read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
I would like to hook up a New Digital Themostat. Since I
I would like to hook up a New Digital Themostat JA: I'll do all I can to help. How long have you been dealing with this? Customer: Since I woke up this Morning JA: Do you plan on doing the work yourse… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
I have a Honeywell L8148E aquastat that the transformer ran
I have a Honeywell L8148E aquastat that the transformer ran hot on and started leaking oily wax from. … read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
Rheem Criterion II. Sometimes doesn't start. Inducer will go
Rheem Criterion II. Sometimes doesn't start. Inducer will go on and off and start sometimes but next time inducer motor will cycle on and off again before it starts … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
I have a question about refilling my steam boiler. Just
I have a question about refilling my steam boiler JA: I'll do all I can to help. How long have you been dealing with this? Customer: just today JA: Do you plan on doing the work yourself? Customer: ye… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
My lennox heater is not heating. The thermostat is set. I
The thermostat is set. I did not check the filter, but it is only 10 months old and the fan is running, when I just trun on the fan … read more
Airheatman
Airheatman
Heating & Air Conditioning Contractor
6 years college
1,836 satisfied customers
Carrier furnace 58mcb080-20 gas valve will not open... i
carrier furnace 58mcb080-20 gas valve will not open... i confirmed 24 volts going to valve... replaced the valve and same problem... i jumped 24 volts from the transformer and it opens no problem... n… read more
Billy
Billy
Journeyman Service Technician
State Licensed Mechanical Contractor
9,330 satisfied customers
I have 30 year old gas furnace (no air conditioner). the
Hi, i have 30 year old bryant gas furnace (no air conditioner). the problem is that the fan doesn't stop. searched internet and learned that mostly the problem is with the fan limit switch. however, i… read more
Webb-Guy
Webb-Guy
tech.
73 satisfied customers
My thermostat is cycling on and off vert frequently, about
my thermostat is cycling on and off vert frequently, about 20 to 30 seconds each … read more
HVAC Guru
HVAC Guru
Service Technician
Associate Degree
682 satisfied customers
My unit is only 2 months old, just tried heat because of
My unit is only 2 months old, just tried heat because of cold weather. All it does is blow cold air, even if set on 80 degrees … read more
Phil
Phil
Mechanical Engineer
8,824 satisfied customers
Can the AC run if a thermostat is blank and the switch with
Can the AC run if a white Rogers thermostat is blank and the switch with gas on one side and electric on the other is in the middle, which would appear to be the unmarked off position? … read more
gotoman for ac
gotoman for ac
HVAC Service manager and owner
Associate Degree
4,135 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x