[patrocle]

Hello!,

So everything was fine and then this morning wake up about 5.30 am and i notice some cold wind coming out of my vents! Looking on my phone at the Sensi app and it say 63'f, and it suppose to be like 70'f+ at that hour based on my schedule. So i turned the heat of to see if the fan stop and it did not! I went to the thermostat Emerson UP500W (installed 3,4 weeks ago new) unplug it from the wall and the fan still working, so i went to the fuse panel and turned fuse to off for the A/C and all stopped.

So at this point not sure whats going on. I have Carrier
Model: 48SX-036080321AA Witch is cambo heating & a/c system, here is some manual:
http://dms.hvacpartners.com/docs/1009/Public/04/48SX-4PD.pdf
or this link:
http://data.manualslib.com/pdf/3/256/25593-carrier/48sx.pdf?301cb48f6bd77f0f1fee95ae3b3e5b71.

I have attached some pictures,of the unit and the side witch i think there is the heat pump or something.

Also reading around,some talk about a "Limit switch" that something maybe wrong with it!? and needs reset, but not sure witch one is it exactly.

Any advice on this will appreciate.

Thanks,

 

[roughneck]

Are those pictures all from today? If so why is the condenser fan running? Is there a call for heat at the unit?

 

[patrocle]

Oh, sorry that picture with running condenser fan was from few months back (summer) when i had other problem with my a/c unit.

Now fan not running.

Writing now an update,what i found...reply will be posted within few minutes....

 

[patrocle]

So i turned everything on, it is on heat , the fan kicked on but no heat !
I go in top of the house and before i open anything to see if there are any error light codes i put my had on the right side vent and i fill heat coming out.
I open the metal plate i see on the panel the red light does not blink so that means there is no error codes, and the burner motor and flame is running. Wife come out and said that the heat is coming in the house!
So at this point not sure exactly what it happen. Maybe a dirty filter? Is there a filter by the burner there?

Thanks for advice.

 

[patrocle]

Here is a video too:

Still researching why it stopped working and then worked again.

 

[planomateo]

I just dealt with some furnace issues myself, I ended up swapping control boards to fix my issue where the igniter would light but no gas unless I wiggled the cables.

Quick summary of what I've learned about the sequence of operation (cliff notes version) below...

1- Induction fan turns on
2- Igniter lights/sparks
3- Gas ignites via igniter
4 - blower motor engages 30-45 secs later

Decent video on the sequence of operation

 

[beenthere]

So i turned everything on, it is on heat , the fan kicked on but no heat !
I go in top of the house and before i open anything to see if there are any error light codes i put my had on the right side vent and i fill heat coming out.
I open the metal plate i see on the panel the red light does not blink so that means there is no error codes, and the burner motor and flame is running. Wife come out and said that the heat is coming in the house!
So at this point not sure exactly what it happen. Maybe a dirty filter? Is there a filter by the burner there?

Thanks for advice.

Probably a filter in your return grille, see if it is dirty. Could also be that your A/C coil is dirty and causing low air flow.

 

[patrocle]

I just dealt with some furnace issues myself, I ended up swapping control boards to fix my issue where the igniter would light but no gas unless I wiggled the cables.

Quick summary of what I've learned about the sequence of operation (cliff notes version) below...

1- Induction fan turns on
2- Igniter lights/sparks
3- Gas ignites via igniter
4 - blower motor engages 30-45 secs later

Decent video on the sequence of operation https://www.youtube.com/watch?v=9OaLbNy9RoM

Thanks for that video! Good to know how a furnace works!

 

[patrocle]

Probably a filter in your return grille, see if it is dirty. Could also be that your A/C coil is dirty and causing low air flow.

So normally the return filter is at highest point? in my case in the upstairs on the hall. I do have a filter on the first floor too.
Now for that A/C Coil is it this one here,see attached picture.

Thank you!.

 

[roughneck]

That's the condenser coil, which appears dirty. The evaporator is the other coil mounted in the middle of the unit. Both are used during air conditioner operation. Sometimes packaged units also have a filter, or a spot for a filter, in the return section of the unit.

 

[patrocle]

Thank you for your advice.

I may have to get someone professional to check from a-to-z to make sure everything is 100% clean and the way it suppose to work.

Thanks,

 

[patrocle]

Well it was working fine and this night it happen again. Had to turn off/on A/C breaker to make the heat go again.

 

[roughneck]

That's a safety shutdown of some kind. Do not allow the unit to keep operating that way as it could damage something.
Time to get out your tools and start diagnosing, or get a service call.
Make sure the flame rod is clean. And the burners are firing correctly at the correct gas pressure.
Some of the diagnosing work involves working with live electricity and natural gas.

 

[patrocle]

Thank you! Will get ASAP the pro.

Regards.