Carrire Gas Furnace blow only cold air

Hi All,

I have a Carrier gas furnace, model number, 58GP-100-111-CA with the control board model HH84AA011. Currently, the furnace only blow the cold air. I replaced with a new control board (compatible, also from Carrier). same problem. There are no current in those thermostat wires (C, Y, GC, GH, R, W)
However, I measured that the PR-1 amd PR-2 is 115V (input to the transformer) and the Sec2 and Sec1, the output from the transformer, is 24V. The new control board has a 3AMP fuse, fuse and circuit breakers are both OK. I don't know what to do next.

If I connect the red "R" wire directly to the Sec 1 wire,(by pass the board) the burner will ignite. Can someone help me wiht this problem?

Thanks a lot

DIY_168

 

24 volts go into the board but not present at the R terminal? if fuse is good, my first thought is the board. is this without any tstat wires connected? where does the wire go to now as opposed tothe SEC1 term that makes it work?

 

Thanks HVAC4U,

Currently, there is a "Ritetemp" programmable thermostat attached. Before I placed the new control board, the thermostat work fine. 2 days ago, the furnace started to blow only the cold air and the fan won't turn off (setting is on auto). a service guy come in and measure the voltage and said, between the GC and the R wire there is no voltage. (supposed to be 24). So I bough a new control board from a local Carrier dealer and replaced the board myself. The same problem exist. The furnace still blow cold air. The new board come with a fuse (3AMP) and it was OK. all the thermostat wires are in their position. I plugged the exact position as the old board.

There are 6 terminals, namely C,Y,GC,GH,R,W
one wire connect to C;
two joint wire connect to Y;
green wire connect to the GC;
No wire connect to GH;
red wire connects to the R;
and white wire connect to W.

 

What happens if you just hook up the R and W wires at the t-stat?

 

When I connect R & W wire, nothing happened. Using voltage meter, I measured the terminal R and W, zero volt. however, between the GH, and W 24 Volt. currently, there is no wiring on GH.

 

by the way, I hit the little black button on top of the heatering unit, and then, I took the thermostat's cover out, I can measure that the between the R and W wire, there is 24 voltage. Does it mean my old wiring onthe thermostat does not match the new board?(still Carrier's upgard version)
However the burn still won't start.

 

I figured out that it was a heat sensor... What that sensor, that is located behind the gas control valve, does is when the burner warms the air and that air get hot enough the sensor switches on the blower to blow the hot air. NOW it seems like everyone here is haveing the same problem as I did...

1. look behind the gas control valve there should be 2 wires connected to something that is screwed into the sheet metal. One should be red and the other should be brown... if you follow them down the brown connects to SEC1 and the red wire connects to LIM1.

2. What I explained in the first part is the heat sensor/switch... I don't really know which one it is.. At the sensor/switch leave the brown wire in and take the red wire out.

3. Take that red wire and touch it to the brown. OR in other words unplug LIM1 from the sensor/switch and touch it to SEC2 on the sensor/switch. When you do this the burners should light up.. if it doesn't then something else is wrong. If you hold it there long enough the air will heat up and the switch will eventually turn the fan on.... Doing this will NOT keep the heater on 24/7... Your furnace will shut off once the desired temp. is reached.

THIS IS ONLY A TEMP FIX!!! BUY ANOTHER HEAT SENSOR/SWITCH... Should run about $20ish.... Part number HH12ZA251A or equivalant.... I think it's a heat switch....

If you want a crude paint shop drawing of what I am talking about e-mail me..

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