Safety fuse blows in cooling mode
#1
06-12-16, 06:42 PM
Safety fuse blows in cooling mode
heating mode everything ok. in cooling mode i can hook up three wires but when i hook red wire to r terminal 3 amp fuse blows. the condenser is currently not connected. what could be the problem
#2
06-12-16, 07:10 PM
Forum Topic Moderator
Some more information would help.
Did this problem just start?
Is this a newly installed system?
Is the control wire to the outdoor unit connected at the furnace?
Make and model numbers might also help us to help you.
A chewed low voltage wire to the outdoor unit is one of many possibilities.
Did this problem just start?
Is this a newly installed system?
Is the control wire to the outdoor unit connected at the furnace?
Make and model numbers might also help us to help you.
A chewed low voltage wire to the outdoor unit is one of many possibilities.
#3
06-12-16, 08:03 PM
yes turned on ac for first time and fuse blew. no this is a system that was installed in 2002 out door condenser is not connected at this time. mode of furnace is395cav048111
the two wires to the left red and white are for my humidifier
this shows the model number it's a bryant
#6
06-12-16, 08:45 PM
When you say the condenser is "not connected", what does that mean? Just off? Or are wires disconnected?
Are the low voltage wires connected at the condenser?
Does it blow the fuse the second you connect to R, or only during call for cooling?
Why were wires disconnected? Did problem arise, then wires were disconnected, or were wires removed and problem showed up?
Are the low voltage wires connected at the condenser?
Does it blow the fuse the second you connect to R, or only during call for cooling?
Why were wires disconnected? Did problem arise, then wires were disconnected, or were wires removed and problem showed up?
#7
06-12-16, 09:03 PM
Group Moderator
There's something missing here. In your picture I see the four wire thermostat cable. I see the red and white wires for the humidifier.
Where is the cable (2 wires) going to the condensor unit ?
They aren't in the picture which means you have a spliced thermostat cable somewhere.
Where is the cable (2 wires) going to the condensor unit ?
They aren't in the picture which means you have a spliced thermostat cable somewhere.
#8
06-13-16, 03:08 AM
the condenser is disconnected at the furnace also i have since disconnected the humidifier. so currently only the four wires from thermostat are connected. i tried connect each wire one at a time and then manually start furnace.i was able to hook up the green blue and white but when i tried to apply the red and try to power the furnace the fuse would pop. i disconnected the wires to condenser and humidifier to try to eliminate the sources.
#9
06-13-16, 03:16 AM
the confessor wires as well as the humidifier wires have been disconnected. i was trying to eliminate the problem.i have no problem with heat but when in cooling i hooked up one wire at a time trying to power up each time. when i attach the red and try to power up the fuse pop right away. i also tried a new thermostat which also had same result.
#10
06-13-16, 04:01 AM
When you say heat works, I assume R is connected then...
Hook up R first with stat off(no call for heat or cool).
Add G and test fan function.
Add W and test heat
Add Y and test...If at this point you blow the fuse, you may have short between Y/C between furnace and condenser. Check low voltage wire outside. I have seen a weed wacker or two take out low voltage wiring....Or mice/dogs/etc.
You most likey have a short somewhere. We can try to narrow it down.
Do you have an electric meter? You can check for short/ground.
If heat works, it is most likely a problem with your Y wire being shorted/grounded.
Hook up R first with stat off(no call for heat or cool).
Add G and test fan function.
Add W and test heat
Add Y and test...If at this point you blow the fuse, you may have short between Y/C between furnace and condenser. Check low voltage wire outside. I have seen a weed wacker or two take out low voltage wiring....Or mice/dogs/etc.
You most likey have a short somewhere. We can try to narrow it down.
Do you have an electric meter? You can check for short/ground.
If heat works, it is most likely a problem with your Y wire being shorted/grounded.
#12
06-13-16, 07:35 AM
Group Moderator
The OP has told us that the fuse blows without the condensor connected at the furnace board.
So... we can eliminate discussing the condensor wiring for now.
The red wire is the power wire to the thermostat. The white, green and yellow wires are switched functions back from the thermostat to the board.
Blower on is R --> G
Heat on is R --> W
Cool on is R --> Y and G
With no thermostat wiring connected at the furnace...try connecting a jumper from R to Y. See what happens. If the fuse blows... you may have a defective control board.
So... we can eliminate discussing the condensor wiring for now.
The red wire is the power wire to the thermostat. The white, green and yellow wires are switched functions back from the thermostat to the board.
Blower on is R --> G
Heat on is R --> W
Cool on is R --> Y and G
With no thermostat wiring connected at the furnace...try connecting a jumper from R to Y. See what happens. If the fuse blows... you may have a defective control board.
#13
06-13-16, 10:00 AM
Forum Topic Moderator
I have seen quite a few people connect blue to B or O/B when it should be somewhere else. Blue should be connected to Y at the stat.
What thermostat are we using?
What thermostat are we using?
#14
06-13-16, 03:08 PM
I bought a meter on the way home tried again putting wire back on one by one and when I did get to blue wire fuse blew. Tried my new meter and the blue was bad. Thank you so much for the help. I picked up some wire and was able to run it down steps to furnace in basement and everything works great. Now I need to run new thermostat wire behind walls. Thank again
#15
06-13-16, 09:03 PM
Group Moderator
