AC condensing unit problem
JackpipE
my AC system. I have split system and I already replaced the 24V
transformer for the fan (the unit an the attic) and got it to work.
However, the condensing unit is still not working. Here is a picture
of the electric parts on the unit: http://e-pixel.net/AC_condensing_unit.jpg
I have power 220V coming into the unit and I have 24V now coming to
the unit from the attic fan. I was trying to follow the 24V on the
condensing unit but it goes inside the coil to the bottom (labeled on
the picture) and I can't find 24V anywhere on the unit. I checked
every other wire with the brown 24V wire and I don't have 24V
anywhere.
Can someone help me out here. What's inside the unit where the blue
24V goes to? What else could be damaged here?
Thanks in advanced for all your help,
Jack
Zyp
You have a CARRIER 38ED high eff. from the 80's. The electronic board is a
"anti short - cycle" timer. Remove it from the circuit. Your unit will
light if you have 24 v from the two wires coming in. You'll have to
'by-pass' the c.b. Good luck.
--
Zyp
Stormin Mormon
--
Christopher A. Young
Learn more about Jesus
www.lds.org
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"Zyp" <nos...@yahoo.com> wrote in message
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JackpipE
So is it the delay timer (electronic board) that got shorted out ? I
would rather replace whatever I damaged than try to remove it from the
circuit and damaged something else.
> You have a CARRIER 38ED high eff. from the 80's. The electronic board is a
> "anti short - cycle" timer. Remove it from the circuit. Your unit will
> light if you have 24 v from the two wires coming in. You'll have to
> 'by-pass' the c.b. Good luck.
>
butwhat
>
> - Show quoted text -
Do you have power coming back from your thermostat when the unit is
calling for air? I would check for voltage at the stat and from the
stat first. If you have an electronic stat you could have blown the
stat board. Do you have heat?
Mikepier
> JackpipE wrote:
> > While replacing thermostat I have shorted out control transformer on
> > my AC system. I have split system and I already replaced the 24V
> > transformer for the fan (the unit an the attic) and got it to work.
> > However, the condensing unit is still not working. Here is a picture
> > of the electric parts on the unit:
> > into the unit and I have 24V now coming to
> > the unit from the attic fan. I was trying to follow the 24V on the
> > condensing unit but it goes inside the coil to the bottom (labeled on
> > the picture) and I can't find 24V anywhere on the unit. I checked
> > every other wire with the brown 24V wire and I don't have 24V
> > anywhere.
> > Can someone help me out here. What's inside the unit where the blue
> > 24V goes to? What else could be damaged here?
>
> > Thanks in advanced for all your help,
> > Jack
>
> You have a CARRIER 38ED high eff. from the 80's. The electronic board is a
> "anti short - cycle" timer. Remove it from the circuit. Your unit will
> light if you have 24 v from the two wires coming in. You'll have to
> 'by-pass' the c.b. Good luck.
>
> --
>
> - Show quoted text -
My thermostat has a built in "anti cycle" feature, in that it will not
allow less than 5 minutes between compressor cycles. I don't know if
that board does the same thing, but just figured I let you know in
case the board is bad, you can use the T-stat as a substitute.
Moe Jones
SOLID-STATE TIME GUARD II CIRCUIT,
protects unit compressor by preventing short
cycling. Time Guard II circuit provides a 5 ą 2minute
delay before restarting compressor after
shutdown for any reason. On normal start-up, the 5minute
delay occurs before thermostat closes. After
thermostat closes, the Time Guard II circuit then
provides a 3-second delay to prevent contactor
chattering.
--
Moe Jones
http://www.MoeJones.info
JackpipE
> calling for air? I would check for voltage at the stat and from the
> stat first. If you have an electronic stat you could have blown the
> stat board. Do you have heat?
Yes I do have heat because I already replaced the transformer on the
furnace that I also have blown.
Yes, I do have voltage on the thermostat.
From the attic unit (fan) there is 24V going to the thermostat. 3
wires white, red and green connecting to RC, G and Y on the
thermostat. There are 24V on the thermostat.
2 wires 24V go to the condensing unit. I do have the 24V on the
condensing unit at the end of the wire, but I can't find the voltage
on the electronic board or any other wire on the condensing unit as I
described in the first message opening this discussion.
I appreciate all your help but most of what you say sounds Chinese to
me. Is there an easy way I can test what's wrong with my condensing
unit? Can someone say with high confidence that it's the electronic
board could have blown ?
Thanks,
Jack
JackpipE
http://groups.google.com/group/alt.home.repair/browse_thread/thread/b0aa15c4a88d6977?hl=en#
I took the condensing unit apart and follow the 24V blue wire inside
the unit. As you can see on this picture: http://e-pixel.net/AC_condensing_unit_inside.jpg
the blue 24V first goes into the "red thing" (don't know what it is)
and then it goes into the green thing. When it comes out, there is no
voltage on the wire. There is voltage (27V) when it comes out of the
red and changes from blue to yellow wire but no voltage coming out
from the green thing.
What is the red and green ? how can I replace it as it seems to be
permanently attached to the pipe?
The yellow wire that comes out of the green goes to T1 on the
electronic board: http://e-pixel.net/AC_condensing_unit.jpg. The other
24V is on T3.
So I have no voltage on the electronic board. Can I skip the green and
red parts inside the unit and connect the 24V wire directly to T1 on
the board?
Jack
M Q
Your posting is quite hilarious if you don't look at the photo
at the same time.
Once I looked at the photo, my guess is that they might be high and low
pressure limit (cutout) switches. They would be there to shut off
the compressor if the system is (way) over- or under-charged.
Do you have a schematic? Usually it is either pasted inside a door
or panel, or hidden inside and envelope inside a door or panel.
If my guess is right, and your analysis is correct (check again),
then you might end up having to hire an HVAC professional to deal
with it. But it really seems incredible that shorting something
at the thermostat would fry anything at the condensing unit.
Typically you would blow a fuse at the air handler.
JackpipE
J.H. Holliday
news:9fd1825f-733d-43e2...@34g2000hsh.googlegroups.com...
Why did you take it apart-- was the system working? If not, what were the
symptoms?
Moe Jones
1. First shut down the 24v power to the condensing unit.
2. Cut the wires going to # 2 pressure switch about 6" to 8" from the switch
and tie them together to bypass the switch.
3. Turn power back on and see if it works then turn back off.
4. If it does then find why the switch was blocking power. Could the switch
be defective or has it sensed defective pressures?
5. If you are not sure what to do then find a HVAC person that knows what
they are doing so you don't do anymore damage to your A/C.
JackpipE
> 1. First shut down the 24v power to the condensing unit.
> 2. Cut the wires going to # 2 pressure switch about 6" to 8" from the switch
> and tie them together to bypass the switch.
> 3. Turn power back on and see if it works then turn back off.
> 4. If it does then find why the switch was blocking power. Could the switch
> be defective or has it sensed defective pressures?
> 5. If you are not sure what to do then find a HVAC person that knows what
> they are doing so you don't do anymore damage to your A/C.
>
I eliminated the pressure switch #2 and it did work.
1. Can I run the system without the switch for now?
2. Are the switches replaceable as it seems to be installed there
permanently (from what I can tell).
3. As Moe mentioned, could there be a defective pressure the would not
let the voltage through the switch?
Thanks,
Jack