How JustAnswer Works:

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

Ask Rick Your Own Question

Rick
Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 13135
Experience:  40+ yrs. experience as a licensed oil & gas technician.
Type Your HVAC Question Here...
Rick is online now
A new question is answered every 9 seconds

Hi - I have two Goodman furnaces, but Im having a problem

Resolved Question:

Hi -

I have two Goodman furnaces, but I'm having a problem with one. I keep getting a pressure switch stuck open/closed error. We switched the control boards between the units (it was the same board) and I still get the same error. Do you have any other ideas as to why the pressure switch error keeps happening?

Thanks.
Submitted: 5 months ago.
Category: HVAC
Expert:  Rick replied 5 months ago.

Rick :

Welcome, my name is XXXXX XXXXX X will do my best to help you with your issue.

Rick :

You could have a bad pressure switch or there could be a blockage in the exhaust vent

Customer:

HI

Rick :

Or your draft inducing fan could be weak and not provinding adequate draft

Customer:

when the unit comes on we hear the click in the switch

Customer:

doesn't that mean it's working?

Rick :

I don't think your hearing the pressure switch click

Rick :

You might be able to hear it if the fan wasn't running

Rick :

but the fan makes too much noise for you to hear the switch

Customer:

yes...we do hear a click when the service panel is open and you put your ear next to the switch

Customer:

yes the fan does make some noise, but if you listen carefully i hear a small click

Customer:

is there a way to test the pressure switch?

Customer:

or to test the draft inducing fan?

Rick :

You can check for continuity through the switch with an ohm meter. You need a manometer to check the draft

Customer:

this is a Goodman high efficiency furnace

Rick :

Same procedure no matter what furnace you have

Customer:

the unit works if we replace the switches with ones that have lower gauges

Rick :

"lower gauges"?

Customer:

lower sensitivities

Customer:

there is a number on the switches

Rick :

Then that could be an indication of a draft problem

Customer:

ok...what types of draft problems should I check for?

Customer:

the exhaust vent is clear

Rick :

How do you know that? It could be a blocked vent (including any sags in horizontal vent piping runs) or could be a weak fan (only a manometer test will confirm this)

Customer:

the vent is made of 3 inch pvc piping

Rick :

sags can fill with water (condensate) restricting the air flow

Customer:

the piping is rigid so any condensation should drain

Rick :

BotXXXXX XXXXXne is you need a manometer to be sure. The fact that the unit runs with a switch that has a lower pressure rating indicates a draft issue. If you are sure there are no vent obstructions then the fan is the most likely culprit or possibly too long a vent run. A too long vent run doesn't always cause a problem at first but it can show up as the fan output weakens a bit over time

Rick :

One other possibility and it might not apply to your unit

Rick :

Some unit have a condensate drain at the beginning of the run. If the drain is (partially?) plugged this too can affect the draft. The only other possibility could be a (partial) blockage where the vac tubes connect to the furnace (not the switch)

Rick :

You can try poking a straightened paper clip into the hose port on the furnace (not the switch)

Customer:

there are two tubes...on going into the furnace and the other into the fan?

Customer:

what can clog the tubes? water?

Rick :

Water can clog the tubes but it usually shows in the tubes and you said you cleaned them. Blocked ports are rare but they do happen. They can get blocked by debris as well

Customer:

ok...I'll try cleaning the ports...if the manometer shows the fan is too weak...how much of a stronger fan would I need?

Rick :

You should replace it with the OEM (original equipment) fan. The only reason the orignal fan wouldn't do the job is because the run is too long

Customer:

if the run is too long what would be the corrective action? moving the furnace?

Customer:

the holes in the unit are for two inch pipes and we put three inch

Rick :

Take a different shorter route with the vent.

Customer:

so i though the three inch pipe would compensate for the longer run

Rick :

The size of the vent piping is determined by the furnace btu input and the length of the run. I only mentioned the length of the run as a possibility. I wasn't saying it was likely

Rick :

The vent length limits are listed in the installation manual

Customer:

ok...i'll double check the limits for the length of the run...so to recap it good be clogged ports, a weak fan or the run might be too long...any other possibilities?

Rick :

Check the vent condensate drain (if you have one) for blockages. It could also be the original switch too is faulty. Even though you hear it click doesn't mean it's making good contact. You need to check for continuity through the switch while the fan is running or check for 24 volts (to common) in and out of the switch while the fan is running.

Customer:

the unit is only two years old...do the switches go bad that often?

Rick :

These switches work on extremely low pressure so they are very sensitive. Consequently they can fail at any time. It's not common for a switch to fail in 2 years but it does happen

Customer:

if it's a switch issue, should I replace both at the same time?

Rick :

It's best to determine which one is the culprit in this case. If your unit was 20 years old I'd say replace them both.

Customer:

so since the unit works with switches with lower pressure ratings then would the more probable cause be the switch instead of the fan?

Rick :

No way to know from that alone. Could be either one

Rick :

are you still there?

Customer:

yes

Customer:

ok...the problem is recurring as well

Customer:

we were able to get the unit to work by resetting the control board, the unit works for sometime and then the problem happens again

Customer:

does this indicate anything?

Rick :

Could point to a balky pressure switch. Sometimes it works sometimes it doesn

Customer:

what do you mean by balky?

Rick :

sometimes it works sometimes it doesn't

Customer:

i see...ok...thanks for your help

Rick :

You're welcome!

Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 13135
Experience: 40+ yrs. experience as a licensed oil & gas technician.
Rick and 4 other HVAC Specialists are ready to help you

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. Jimmy Bagley, IA
< Last | Next >
  • 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. Jimmy Bagley, 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!!!! Alex Los 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. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, 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. Esther Woodstock, 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. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • gotoman for ac's Avatar

    gotoman for ac

    HVAC Technician

    Satisfied Customers:

    4657
    51 years of experience install design and repair of all makes and models of AC
< Last | Next >
  • http://ww2.justanswer.com/uploads/SE/ServiceTechRus/2012-6-7_2119_056.64x64.JPG gotoman for ac's Avatar

    gotoman for ac

    HVAC Technician

    Satisfied Customers:

    4657
    51 years of experience install design and repair of all makes and models of AC
  • http://ww2.justanswer.com/uploads/AL/alumalite/2012-5-10_234018_shutterstock506249951forJA500.64x64.jpg Phil's Avatar

    Phil

    Mechanical Engineer

    Satisfied Customers:

    3888
    Retired HVAC/ Electrical & Boiler contractor. Industrial
  • http://ww2.justanswer.com/uploads/skibum0101/2008-12-16_015819_just_answer.jpg Rick Mather's Avatar

    Rick Mather

    HVAC Technician

    Satisfied Customers:

    3132
    35 years experience, HVAC
  • http://ww2.justanswer.com/uploads/RY/Rygis20/2011-5-7_3143_DSC5324.64x64.JPG Matthew's Avatar

    Matthew

    HVAC Technician

    Satisfied Customers:

    1994
    14 years experience in the HVAC field of service, installation, Manual J & D calculations
  • http://ww2.justanswer.com/uploads/KE/kentguidry/2011-9-26_214316_0059.64x64.jpg Kenton Guidry's Avatar

    Kenton Guidry

    HVAC Technician

    Satisfied Customers:

    962
    12 years install/service experience.
  • http://ww2.justanswer.com/uploads/solarman1947/2009-12-13_223915_phpkKBcXq_c2PM.jpg Rick Ridley's Avatar

    Rick Ridley

    UK Heating Engineer

    Satisfied Customers:

    871
    Retired But have had 30 years on the tools, Ex CORGI
  • http://ww2.justanswer.com/uploads/Ironheadfan/2009-12-18_222416_pump_005.jpg Tom's Avatar

    Tom

    HVAC Technician

    Satisfied Customers:

    770
    16+yrs HVAC/R service. Residential Commerical Industrial