Inspected to find causality behind no heat and now nothing works...

I noticed, in the first winter of being in my new house, that the heating system didn't blow hot air to warm my (pregnant) wife and I. It would blow air, but nothing was getting warm. I inspected everything I could find online and ultimately ended up bypassing the thermostat and I got hot air. Once. I put everything back together and now nothing works. I only disconnected the two wires, and now, after verifying everything is snug, I can't get anything. I have a completely useless heating system. It is a Coleman LX Series heat pump attached to an Intertherm e2eb-012hb blower, a mortex coil and a honeywell RTH7600D Thermostat. Does anyone know what the wiring should look like for everything to function as it should? I can take pictures and can give you any other information you need. Thanks in advance.

 

There is a good chance that you shorted something while you had the t'stat cables off. If you go to the air handler and locate the control board you should see a fuse on it. Usually 3A although it could be 5A.



Does your air handler have back up heat coils.
Was the outside compressor running when you were checking for heat ?
With a heatpump the two lines on the outside condensor should be warm to hot.

 

You were right, but there is still nothing. I replaced the 5A fuse and it isn't blowing, but I still get nothing.

It doesn't have back up coils that I am aware of. I do not know if the compressor was running or not, I just know it worked once. I don't feel any heat coming from them.

 

You said you bypassed the thermostat and got it to work. How did you bypass the thermostat? You also said you only disconnected "the two wires". What two wires did you disconnect? Has anything recently been done to the system like installing a new thermostat?

 

I disconnected the red and white wire. It worked and I got heat, but nothing has been done to the system recently. I had the breaker shut off and verified with a voltmeter that there was no power prior to messing with any wires and had it shut off before I switched it back too.

 

Was the fuse blown ?
Post the wiring colors/thermostat base.

 

Yea, it was blown. however, it isn't blowing anymore. The wires at the thermostat are as follows:

label / actual color wire
C / Black
G / Green
Y / Yellow
O/B / Orange
RC / jumpered to R
R / Red
AUX / White
E / Brown
L / No Wire

 

Welcome to the forum!! Here is a link to a manual that shows the wiring diagram on page 18 (figure 20):

http://www.nordyne.com/Literature/359a.pdf

 

PJmax,

Upon further inspection, it does have a backup coil. I am not sure if this affects the situation negatively or not.... but if it helps...

 

After replacing the fuse is 24 volts present between r and com?

 

Where would I test that? at the heat pump?

 

If you had the wires disconnected without turning off the power to the heating system, it's possible that you shorted the 24VAC from the transformer. Many systems have an automotive style fuse to protect the transformer from a short circuit. It's possible that the fuse (if one is used) is blown. Something to check. Usually, if a fuse is present, it will be on the control board in the furnace/air handler.


(Moderators note: This post transferred from a second thread on the same topic.)

 

You test for 24vac at the control board where the thermostat wires connect in the air handler.
Check between C and R.

 

I checked for voltage and it registered 27.6VAC and as I was saying earlier, there was a burnt 5 amp fuse inline but I replaced it. It is not burning out any longer and nothing still works.

 

Ok.... then the transformer is good.

Remove the thermostat from the base. Never short any terminal to C.
Temporarily hold a piece of jumper wire on R and G. The fan should run. Yes or no.
Now hold a jumper from R to Y. The outside compressor should run. Yes or no.
Now hold the wire from R to W. The electric heat will come on. It may take a minute. Yes or no.