HVAC

Have HVAC questions? Ask an HVAC Expert for answers

Ask an Expert,
Get an Answer ASAP!

I've been working with Billy HVAC. I had a limit switch

Customer Question
I've been working with Billy...
I've been working with Billy HVAC. I had a limit switch problem relative to short cycling which turned out to not be a limit switch.. it has been between 2 to 13 degrees here in Chicago and house stays at 66.
Submitted: 4 months ago.Category: HVAC
Show More
Show Less
Ask Your Own HVAC Question
Answered in 11 hours by:
12/29/2017
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 4 months ago
BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 23,041
Experience: Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
Verified

I am sorry to hear you still have issues. Are you getting a particular blinking pattern on the circuit board light?

Ask Your Own HVAC Question
Customer reply replied 4 months ago
I will look..... My people here think it's a total Duct issue, and I'm not convinced of that of course. My son thinks that maybe I need to get in inline ducts, fans in the crawlspace to equalize the coldness because it's not a finished crawl space. I did see a drop in the elbow of the duct from 75 to 66 as it was going into the crawl space. It was a very big precipitous drop is 10 degrees. You think that could be maybe clogged. It does get pretty hot to 180 and then it stops as you know so that can't be a flame burner dirtyness could it be? Sorry about all the ideas I hope you can knock them all down and I will try to find this thing that you're telling me.
Customer reply replied 4 months ago
I am sure my HVAC guy would have seen that light no..who knows..
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 4 months ago

It could possibly be duct...but usually the duct is in place and the furnace ends up being too big. Same issue but different perspective.

Has the blower speed been increased yet?

Ask Your Own HVAC Question
Customer reply replied 4 months ago
but it didn't show on same day, and now it's 14 to 15 degrees and it seems warmer now. These problems were occurring at -1 to 7 degrees outside
Customer reply replied 4 months ago
Same day, 68, now warmer outside, could that be it.
Customer reply replied 4 months ago
Warmer inside at 71.
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 4 months ago

Has anyone mentioned about just cutting a supply register in for the crawlspace? Not so much to heat the crawl space but to move more air.

Keep in mind....it is not uninsulated crawl space....this is the furnace running too hot.

Ask Your Own HVAC Question
Customer reply replied 4 months ago
What about dirty gas sensors..You did not mention that. That was not checked....I do have a register that was cut just off the furnace out duct.
Customer reply replied 4 months ago
I also saw strange drop at an elbow point at the beginning of the crawl space as it went in from 77 to 65..want to hear your thoughts about the sensor idea
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 4 months ago

Dirty sensors will not have anything to do with a limit code.

LIMIT is a very common condition when filters are restricted, airflow slowed etc.

With your temp readings...you very simply are making more heat than what the system can get blown through.

Analogy - you have a water pump capable of pumping 10 gallons a minute.

Your water hose is only capable of 5 gallons a minute.

This causes backpressure on the pump....

This will not be sensors or electronics...it is just the relation of heat being made by the furnace to the amount of heat the blower and duct can move.

You need either less heat or more air......

Ask Your Own HVAC Question
Customer reply replied 4 months ago
But sensors can deal with short cycling for other reasons?
HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 4 months ago

Yes but these are simply heat activated bimetal switches.

The bimetal reacts to heat and warps..it is a open or closed switch...not a dc signal.

The temps you have mentioned are not low enough to be be shortcycled by a limit.

Lets say furnace is tripping at 120f discharge...that would be a limit switch that is bad.

Lets say you are tripping at 150-180...that is a limit switch acting as it should by limiting the heat load in the furnace.

Ask Your Own HVAC Question
Was this answer helpful?
Ask BillyHvac Your Own Question
BillyHvac
BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 23,041
23,041 Satisfied Customers
Experience: Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics

BillyHvac 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

6,938 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
I have a Model M3DH30B2A Maytag Dehumidifier. The fan's
I have a Model M3DH30B2A Maytag Dehumidifier. The fan's running, the bucket's empty, but there's no water coming out. Is there anything I can do? … read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
I have an estimate for a new HVAC system. Could you take a
I have an estimate for a new HVAC system. Could you take a look and see if reasonable in your judgment? My home is approx 13500 square feet with three bedrooms, two baths, and he is going to put an ad… read more
Gaztech
Gaztech
Technician
Vocational, Technical or Trade School
1,808 satisfied customers
I have a Trane 5-ton, 2-speed 16 SEER unit and a 4-story
Hello. I have a Trane 5-ton, 2-speed 16 SEER unit and a 4-story home that was installed with a Honeywell 4-zone thermostat system. Is this a proper installation? … read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
I just got a DSZC160481 and blower MBVC2000aa-1 Im running
I just got a DSZC160481 and blower MBVC2000aa-1 Im running three zones off this system. with one zone on I'm getting way to much air. How can I cut the system back to 2ton unit and 33% of air and two … read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
The thermostat reads no signal after changing batteries. The
The thermostat reads no signal after changing batteries … read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
Robertshaw RS6220 thermestat turned off today. I replaced
robertshaw RS6220 thermestat turned off today. I replaced the batteries and it came back on, however now the AC nor the Fan will kick on at all … read more
Gaztech
Gaztech
Technician
Vocational, Technical or Trade School
1,808 satisfied customers
I am receiving a if code on my pool heater we had a bad
I am receiving a if code on my pool heater we had a bad stor, … read more
Gaztech
Gaztech
Technician
Vocational, Technical or Trade School
1,808 satisfied customers
My main ac unit just stopped today. The fan on the unit
My main ac unit just stopped today. The fan on the unit won't spin. We had the roof replaced today as well so I'm curious if they accidentally broke something. … read more
Gaztech
Gaztech
Technician
Vocational, Technical or Trade School
1,808 satisfied customers
Every a couple weeks or so, The boiler shuts off and give
Every a couple weeks or so, The boiler shuts off and give E18 error … read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
I come in from work and my house is a hot 85 degrees. My
I come in from work and my house is a hot 85 degrees. My thermostat is blinking cool on. … read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
We have a couple of XB1000 (one 4 ton and a 5 ton) that need
We have a couple of XB1000 (one 4 ton and a 5 ton) that need to be replaced. They are loosing Freon pretty quick. Repair guy said they need to go. We live outside of Memphis TN. Money is tight with th… read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
We have a gas C Heating system we wish to connect radiators
We have a gas C Heating system we wish to connect radiators to a wood burning fire with back boiler. … read more
Plumbers_Mate
Plumbers_Mate
General Manager
Vocational, Technical or Trade Scho
2 satisfied customers
I have just purchased a fridigidare 5,000 btu window AC.
I have just purchased a fridigidare 5,000 btu window AC. It's installed but when looking at the front I am noticing condensation forming on the left front bottom. Where there is a metal bar the runs a… read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
Do I need a return built in every room of the house with a
Do I need a return built in every room of the house with a new A/C system? Ours is super old and getting a new one put in.… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
Trying to locate thermostat panel on Carrier Comfort 13
trying to locate thermostat panel on Carrier Comfort 13 48ES-A … read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 satisfied customers
I recently viewed a potential home to purchase.
Second opinion] I recently viewed a potential home to purchase. ?Coincidently?, the 900 sq ft basement was flooded by what the seller reports that as due to the float in his humidifier getting stuck a… read more
HvacmanSean
HvacmanSean
Owner
HVAC
233 satisfied customers
How much water will dump from the humidifier if float was
How much water will dump from the humidifier if float was “stuck” for a 24-48 hr period? This was my second walk through (first was before the storm) then less than 48 hours after, the basement is wet… read more
Rick the plumber
Rick the plumber
Owner
9,857 satisfied customers
I have a 50D50-842 direct spark control using the spark rod
I have a 50D50-842 direct spark control using the spark rod for flame detection. When the demand for heat is applied, the spark starts, the slow open Honeywell valve delivers gas, the main burner igni… read more
Phil
Phil
Mechanical Engineer
Degree, Mech Engr Technology
6,938 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