# HVAC installation questoin



## cjw615 (Aug 16, 2013)

i Got a new goodman 15 seer 3 1/2 ton gpg 15 and i installed all the ductwork, and the high voltage wires. the unit and thermostat i had before only used 4 wires, white, yellow, green and red(the red in the thermostat was jumped from rc to rh) i hooked up the wires to how there supposed to be hooked up and the compressor comes on then after like 10 min. it will turn off and nothing will happen(thermostat is on cool and set to 69 and fan is on) someone told me i have to get a dual stage thermostat for the unit to run?


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## beenthere (May 30, 2009)

That unit can be controlled by a single stage or 2 stage thermostat. So the thermostat is not the problem. The 3.5 ton model is a single stage cool.


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## WyrTwister (Jul 20, 2013)

Traditionally ;

Red - 24 VAC power or " hot " 

Green - Fan

Yellow - Cool 

White - heat 

Blue - return - Common - other side of the 24 VAC power


This is a cool only , not a heat pump . The older cool only condensers had 2 wires going to the condenser .

The furnace / fan coil unit should run continually when the tstat is " calling " for cool .

Is this an old mercury bulb tstat or an electronic tstat ? If electronic , does the paperwork call for a 5th wire ( blue - common ) ?

God bless
Wyr


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## beenthere (May 30, 2009)

WyrTwister said:


> Traditionally ;
> 
> Red - 24 VAC power or " hot "
> 
> ...



The GPG is a package unit, so its all one unit, no air handler.


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## preeti (Oct 22, 2013)

The goal for HVAC system is to provide proper air flow, heating, and cooling to each room.finding hvac contractors in los angels,orange county & other areas of california its not so easy.


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## WyrTwister (Jul 20, 2013)

Back in the days of mercury bulb Tstats , I have seen a different type of Tstat used for a heat pump , compared to an A/C with gas fired heat .

Remember at least one extra wire ( Orange ? ) going to the change over valve ?

I normally run 8 conductor Tstat cable for heat pumps . Some times all are needed , some times 1 or 2 are left over as spare wires .

God bless
Wyr


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## tenbears (Nov 11, 2013)

When the compressor drops out, check for 24 vac across yellow and common at the control board to see if it's dropping out from t-stat. If you still have 24 vac at the control board you're gonna have to dig deeper.


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