carrier gas furnace problems

[hadvisor]

First of all - this is my first stab at a furnace. Our house is going on 3 years old - I haven't touched the furnace since I moved in(besides changing filter and dusting) We decided to turn on the furnace for the first time today and nothing happened. The fan would blow on when on the on poisition but nothing else. <br /> I took off the access panels and cleaned everything off - nothing. <br /> Turned off power then went over all the connections on the main board and followed wires to check for anything strange(checked the fuse and taped the door switch down) <br /> I set thermostat on 80, reset the switch on the inside of the furnace and turned on the power. The fan kicked in, the ignitor got red hot but it seems like the gas was never released(is there supposed to be a series of clicks like a gas grill?). It shuts off and starts the blinking light process. <br /> What should I be checking next? I assume the control valve isnt opening - either the circuit control board or the switch? Hopefully someone out there knows a bit about this - Thanks!!!<br />Don

 

[steamboatwilly]

Re: carrier gas furnace problems

Put the fan switch on auto.Set the stat.low like sixty.Theres a relay that clicks.The fuel supposed to start flowing,then the igniter kicks on.Then the burner comes on.When the fire box gets about 160 %,the big blower comes on.The stat.ONLY will turn burner off.

 

[D Grass]

Re: carrier gas furnace problems

I would make sure that the gas supply is on. there won't be a series of clicks like a grill. the ignitor gets hot, then there should be one "click" that would be the gas valve energizing, followed by ignition of the burners. If you can, take note of the code the blinking lights are telling you. count the number of slow flashes then the number of fast flashes. there is a chart on the back of the furnace door that will tell you why it is faulting. more than likely it will be the failure to detect flame code but it could be something else. Again, make sure your gas supply is on, the switch in the gas valve itself is on. if you have L.P. tank full?(sorry but you never know) I hope this helps, sorry to ramble on.

 

[hadvisor]

Re: carrier gas furnace problems

I verified gas is on - I did get a code for checking the wiring in the 24v system. When I get back from work I'll run it again and count the blinks. Thanks

 

[SS MAYFLOAT]

Re: carrier gas furnace problems

Is the furnace a 80 or 90% efficient? The 90's have a ventor/burner blower. If it doesn't close the airflow proof switch, the pilot gas will not come on preventing the main gas valve from coming on. This is a safty and should never be bypassed.<br /><br />The airflow switch is a small tuna can sized componet with usually 2 wires and a small air line going to it. Some models have a sail switch, but they are not used widely in residential units.<br /><br />Chain of sequence:<br />Call for heat<br />Venter/blower motor comes on<br />Proof of airflow<br />HSI (Hot surface ignitor) comes on<br />Pilot light comes on<br />Proof of pilot established<br />Main gas valve comes on<br />Finally flame roll out to all burners.<br />Blower comes on to present temp of exhanger.<br /><br />NOTE" 80% units usually have a large exhaust that goes into a chimmney where the 90's have a small 2" plastic exhaust.

 

[dhud64]

Re: carrier gas furnace problems

While my unit is not a Carrier, and I'm not a HVAC person, I had a similar problem on my unit. After paying a service call I found out there is a flame sensor that was dirty. This is simply a small electrode looking thing near the burners. One screw removes the electrode and wire. A light cleaning of this with emery paper does the trick. Maybe you have a similar set up?

 

[hadvisor]

Re: carrier gas furnace problems

It is an 80% unit. This weekend I'm gonna go thru and clean everything out - I read about the dirty sensor and could see that being the problem. There is(was) a lot of dust and buildup in there. One of my wifes friends has a hvac husband - i might flip him some cash...I'll let you know what happens.

 

[BassMan283]

Re: carrier gas furnace problems

Might want to consider having your dealer do the annual checkup. Mine charges 75 bucks to check everything out, clean what needs to be cleaned and check the CO output. Dirty flame sensor is a strong possibility.

 

[hadvisor]

Re: carrier gas furnace problems

Had someone come out the other night - 25 bucks and he cleaned off the whole system and ended up rewiring some at the furnace itself - He took a blue wire out of the picture and he installed a new control unit we purchased. I wasn't home when he came - he told my wife it was mostly installer error - he ended up changing some wiring on the a/c system too. Oh well, 25 bucks well spent. Thanks for all the input!

 

[dhud64]

Re: carrier gas furnace problems

$25 buck is a bargain!!!