Furnace acting up... single mom needs help!!

Old 09-27-08, 06:10 PM
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Join Date: Sep 2008
Location: Manitoba
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Furnace acting up... single mom needs help!!

Hi there!!

I have a Nortron 21 FA 20 furnace, Airtemp 12 1-50 A/C unit (ancient - I know) and a Honeywell RTH4300B1018 stat.

I turned on the furnace this week, and the blower and heat will not shut down after reaching the set temperature and the A/C unit is running at the same time??

This is what I have done so far:

Initially, I thought that a relay might be stuck - so I shut the power off at the breakers overnight - nope still runs like crazy.

Flipped switch on stat to off - furnace still runs... odd?

I have recently done MAJOR interior renovations - thought maybe I doused the stat when I was washing walls... pulled it, replaced the batteries, checked connections for corrosion... nothing, put it back on... everything still running like crazy.

Alrighty... perhaps unit is fried?? I put the old stat back on (that I had replaced a year ago - just for a programmable stat, nothing wrong with old one)... NOPE... everything still running like crazy.

Figured, Ok, maybe I put a nail through the stat wire when I put baseboards back on?? So I pulled brand new wire from stat to furnace - reconnected everything - NOPE still running like crazy - except A/C - now it won't come on at all.

Now I'm wondering if I botched my reconnect (you know how it is, you've been staring at wires all day and start to doubt your diagram)... so this is what it looks like right now...

Furnace Thermostat

C ----Black----- ----red---(splice)---black ---- Y
\ /
A/C Unit

G ------------------------green--------------------- G

O {n/a}

R ------------------------red------------------------ Rc

W1 ---------------------blue ------------------------ W
W2 B {n/a}

So, have I wired it back up correctly??

If yes, am I looking at a relay problem?? If yes, which one??

I'm out of ideas.. please help!!GI2
Old 09-27-08, 06:18 PM
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schematic didn't work

I'll try that diagram again

Furnace has C G R W1/W2
Stat has W Y G O Rc/R B

2 wire from A/C unit - black & red
4 wire from stat - black, red, blue, green

Furnace --> wire colour ---> Stat or A/C

C ---> black ---> A/C

no connection A/C ---->red splice to black ---> Y

G -----> green ----> G

R ------>red----->Rc/R

W1/W2 ------>blue-----> W
Old 10-01-08, 06:50 PM
Join Date: Sep 2008
Location: Long Island
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you hit the stat wire with a nail or something DO THIS.... pull the stat off the subbase,and jump the following pairs of wires with a paper clip 24Vs it is cool you won't get shocked. R-G FAN only...R-Y cooling only...R-W heat only.W2 is your second stage of heat if you have it wired at the furnace.if your stat has only a W1 then you need a 2 stage stat(not a major problem right now).when you do this jumper test see if the other systems come on if they do your Y and W are touching somewhere on the run down to the furnace and its not the stat.if everything runs as jumped i listed the stat is the problem..if you need heat right now remove the Y wire color down at the furnace and tape the end off (thats your cool wire out to the condenser).even if it picks up the W call for heat the low 24V voltage on it won't call the condenser in.check down and around the stat location and see if you might of nailed the W and Y together if your not comfortable with taping the Y wire off down in the furnace just go outside and shut the disconnect down for the condenser.the control within will close but the main power will be off so you can run heat without worrying about the condenser running.
Old 10-11-08, 06:35 PM
Join Date: Sep 2006
Location: british columbia
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ooooooh I'm haveing a service fantasy.............and now u guys r 2

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