HVAC TECHS NEEDED ASAP!

[the gnome]

running a room with a standard heat pump/AC system
w/air handler and condenser unit
the thermostat has a 7 wire hook up and is AA battery operated.
bat/ went out last month , new ones put in and was good.
air handler and condenser unit do not run at all, elec supply is good.
I suspect the thermostat
temps in the 90s+.......

help!

 

[SooperSmurph]

running a room with a standard heat pump/AC system
w/air handler and condenser unit
the thermostat has a 7 wire hook up and is AA battery operated.
bat/ went out last month , new ones put in and was good.
air handler and condenser unit do not run at all, elec supply is good.
I suspect the thermostat
temps in the 90s+.......

help!

When you removed the battery the unit may have reset to a default configuration, you'll need to consult your instructions in order to program it properly for your system.

If you don't have your booklet, google your brand and model and you should be able to find the right setup.

This happened to me last month, plugged in a replacement thermostat after the old one died, the default settings couldn't even flip my A/C on, and temps soared until I pulled my head from my ass and read the instructions.

Does your unit have a digital display? Is there an error message?

 

[the gnome]

thanks for the asap reply sooper

the batteries went dead a few months back with no display,
replaced them and things were golden.

i still had a display on the thermstat andjust replaced bats tonite to check the system... no change.
thinking in my limited HVAC exp. its the themstat f'ing up?

 

[SooperSmurph]

With no error message on the thermostat, it could also be a problem with the unit itself.

But, if both the fan and the compressor are non-operational, the thermostat is the most likely culprit.

No error message at all? When mine was programmed improperly it would attempt to turn the system on, then the word "Recovery" would flash underneath the temperature indicator.

I assume you have had the unit inspected for the summer, and you took care of basic maintenance like filter replacement?

 

[ARTofMAKINGfire]

First of all, a battery going out in a thermostat will NOT reset a unit to "default factory settings". There really isn't any such thing.

It's possible if you have an advanced touch screen thermostat that the thermostat itself could reset the installer settings which tell the stat what kind of unit it is running.

If you have an voltage meter and know how to use it, this is what you do...

First check to make sure no breakers are tripped and you have power to both the air handler and the condenser.

I suspect it is a bad transformer. The transformer takes either 120v or 240v (depending on the voltage of your unit) down to 24v, which is known as control voltage.

Take your voltage meter and check the line voltage (usually wire-nutted) and make sure you have power going into it. If you do, check the "other side" of the transformer to make sure you have the 24v control voltage coming out of it. If you have voltage going in, and don't have it coming out of the transformer OR if it is less than 24v, you need to buy a new transformer and replace it wire for wire the way it is currently installed.

Hope this helps.... Good luck.

 

[ARTofMAKINGfire]

P.S. Check in your thermostat to see if there is a control wire (thin 24v wire) wired into the "C" on the stat. This is the "common" and will power your stat even if the battery dies. So if it is hooked up on your stat, and it lost power, get a new stat. Take note of what color control wire is in each letter on the stat (try to buy the same stat) and put them back the same way they are hooked up on the current stat. This is important or the unit will not operate correctly. I.E. If you put it in cooling mode, it could go into heat mode, etc...

GOOD LUCK!

If you have any more questions you can ask here or PM me.

 

[ARTofMAKINGfire]

One more thing. Check for a burnt electrical smell on the transformer. If you need help locating or identifying the transformer, PM me or ask me here...

 

[SooperSmurph]

First of all, a battery going out in a thermostat will NOT reset a unit to "default factory settings". There really isn't any such thing.

It's possible if you have an advanced touch screen thermostat that the thermostat itself could reset the installer settings which tell the stat what kind of unit it is running.

Most thermostats have multiple settings, one of them is the "default" setting, not sure why this seems so ignorant to you? Basic concepts presented in the user manual for my unit, I guess i'm wrong performing a simple fix which got my unit up and running without calling an overpaid HVAC guy, or am I wrong for suggesting my problem is similar to his? Either way

 

[the gnome]

It's possible if you have an advanced touch screen thermostat that the thermostat itself could reset the installer settings which tell the stat what kind of unit it is running.

If you have an voltage meter and know how to use it, this is what you do...

First check to make sure no breakers are tripped and you have power to both the air handler and the condenser.

I suspect it is a bad transformer. The transformer takes either 120v or 240v (depending on the voltage of your unit) down to 24v, which is known as control voltage.

Take your voltage meter and check the line voltage (usually wire-nutted) and make sure you have power going into it. If you do, check the "other side" of the transformer to make sure you have the 24v control voltage coming out of it. If you have voltage going in, and don't have it coming out of the transformer OR if it is less than 24v, you need to buy a new transformer and replace it wire for wire the way it is currently installed.

Hope this helps.... Good luck.

I have a 110-220 volt meter. i have power to the condenser and air handler.
this was the 1st thing i checked.
I'll get a volt/multi meter and check transformer on the power out side

One more thing. Check for a burnt electrical smell on the transformer. If you need help locating or identifying the transformer, PM me or ask me here...

where is the transformer at? on the air handler?
EDITED:
ok, looked on ehow and its usually mounted in the blower compartment, sometimes behind an inner control box cover panel.

P.S. Check in your thermostat to see if there is a control wire (thin 24v wire) wired into the "C" on the stat. This is the "common" and will power your stat even if the battery dies. So if it is hooked up on your stat, and it lost power, get a new stat. Take note of what color control wire is in each letter on the stat (try to buy the same stat) and put them back the same way they are hooked up on the current stat. This is important or the unit will not operate correctly. I.E. If you put it in cooling mode, it could go into heat mode, etc...

GOOD LUCK!

If you have any more questions you can ask here or PM me.

when the batteries on the stat went out a few months ago it shut down the air handler, and I think the condenser also.
the digi display on the stat was dead, new batteries got it running again.
the stat now has the display up, i put fresh batteries in last nite hoping the ones in it were old.. and nadda.

bwt, i put the stat into heat mode and nadda.

there is no C hook up on the stat i can see,
unless it was on the the bar for 3 hook ups, only 2 wire went to it, B+R,

as you said, the transformer...

 

[the gnome]

AHA!

AHA!

ok, got me a multi meter and went to check the transformer.

i hear an outside condensing unit running?
walk over and its doing its thing?.
into the room i go and its a lovely 82F down from 92 last nite @ 9pm
check the vents and air is a blowin!

WTF?
I'm not as happy as I should be because i don't know why it shut off and what if it does it again... and again tomorrow, next week next month...

so i go to check out the air handler and then it hit me as soon as i see it.... its an attic unit and lays on its side,
there's a safety overflow cut off switch on the condensate pan with the water nearly 1/3 full and barely draining

after AMF told me to check the transformer i went on ehow to prep myself a bit on it.
it was there something clicked in me but didn't hit home when i read the transformer may be in the blower compartment and some units have a safety cut off for the blower when you open the panel to access it.

I have a Q.... if the transformer did blow would the condenser unit still run if the stat was set to go on ?


at any rate this place is so great!
were lucky to be able to get help quick from knowledgeable people

 

[ARTofMAKINGfire]

If the transformer blew, then nothing would be working...

But!! If your condensate pan and drain is clogged with shit, and you have a wet switch, then nothing would run as well...

That could explain the intermittent non operation. Maybe after a few days the wet switch dried out, or the water level in the pan reduced "if its a float switch type" and then unit began running normally...

Clean out the condensate line and make sure there is no blockage to allow all your condensate to drain out!

 

[ARTofMAKINGfire]

Sooper Smurf - I was under the impression that you were saying that a loss of power at the thermostat could affect the settings of a condenser or air handler, which have no settings. They are made to operate one way only. Never used the word ignorant. Never even said you were wrong. I was simply trying to clarify the situation for the gnome so he could get his AC up and running and continue to grow dank ass flowers.

 

[the gnome]

"if its a float switch type" and then unit began running normally...

i didn't clarify in my last post, its the float type switch.
the condensate line was nearly plugged up but after sitting for a few days it dropped water level enough to start back up.
I cleaned the line out using hydrachlroic acid/drain cleaner...

this experience has made me think i need to get a back up stat, transformer, for the air handler and
capacitor for the condensing unit, maybe a fan motor too.
if i had been 4+weeks in bloom.... maybe would have had moldy buds in the time it was down.


thanks again for all your help!

 

[Smokerman]

If you have a condensate pump and the float switch is wired in the low voltage, air handler and a/c will not come on if float is stuck or condensate line is plugged. Also if batteries were dead thermostat will revert back to factory settings by default. Sole purpose of batteries is to retain program in event of power failure.

 

[SooperSmurph]

Also if batteries were dead thermostat will revert back to factory settings by default. Sole purpose of batteries is to retain program in event of power failure.

This is the same impression I was under, total loss of power usually erases user settings in small simple computers like thermostats.

Luckily gnome's problem was almost as simple as a thermostat reprogram, glad you're back up and running!

 

[the gnome]

if batteries were dead thermostat will revert back to factory settings by default. Sole purpose of batteries is to retain program in event of power failure.

the 2 AA batteries died in april,
the stat was dead in the water, put new bat's in
and started back up no probs with any reprogramming issues

 

[ARTofMAKINGfire]

put new bat's in
and started back up no probs with any reprogramming issues

And FYI, a condensate pump in NEVER wired in any way to the either section of the AC unit. It is simply powered by 120 or 240v alternating current.

A wet switch is different than a condensate pump. It is located in an emergency drain pan below the air handler (where the cold coil is/and sweating occurs) so that if the drain in the air handler gets clogged, and begins to overflow into the emergency drain pan, the unit will cut off and not flood the space below. This is what is usually wired to cut off the compressor via low voltage wiring.

 

[ARTofMAKINGfire]

Sole purpose of batteries is to retain program in event of power failure.

Incorrect. Batteries give you the option of powering you thermostat two ways. Either taking it from the transformer in the AC and connecting a common to use the 24v off the transformer, or simply to change batteries and power the thermostat that way.

Most stats have a low battery indicator light that appears when it is time to replace them.

Most stats that have any type of advance setting also have a small backup battery (commonly a LR44) that will keep the installers settings programmed in. There are very few models like this however and very few models that even require any type of installer input. If you have a standard split system AC and have an advanced touch screen stat hooked up to it, it is overkill. These stats are designed to run multiple stage heating and multiple stage cooling units and are mostly for commercial applications.

The only thing you're going to lose if you fail to replace you batteries on time is you cooling/heating schedule if you have a programmable stat.

 

[SooperSmurph]

If you have a standard split system AC and have an advanced touch screen stat hooked up to it, it is overkill. These stats are designed to run multiple stage heating and multiple stage cooling units and are mostly for commercial applications.

And they're much more expensive, kudos for not upselling the "overkill" item like most installers / retailers.

 

[Hammerhead]

mine is like that. if the batt go dead I lose the program temp set points for the turn on/off times. The clock is also incorrect needs to be put back after battery replaced. I dont have any other back up batt in this unit.