The HVAC guy is having some issues with his thermostats burning out and he blames it on the way the furnace was wired. It's a normal 110v residential furnance powered by a 3 wire cord pluged into a normal receptacle. Is it possible for a low voltage thermostat to be burned out by the way the furnace is wired. Also we tested the receptical which reads 120v. (Proper installation)
FAU QUESTION???
- Thread starter joeyman
- Start date
- Status
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: FAU QUESTION???
I dont think so, But is a furnace listed for wiring via plug and cord?
I know this would be a good way in an area that is prone to loosing power allot as it would allow an easer way to power it from a generator. I'm just not sure it is the correct way?
Now don't tell anyone but my own furance has a male pig tail that sticks out of the switch box and the switch is a 3-way which when it is up it's on house power but when it's down it's on the pig tail for generator.
[ August 24, 2004, 09:23 PM: Message edited by: hurk27 ]
I dont think so, But is a furnace listed for wiring via plug and cord?
I know this would be a good way in an area that is prone to loosing power allot as it would allow an easer way to power it from a generator. I'm just not sure it is the correct way?
Now don't tell anyone but my own furance has a male pig tail that sticks out of the switch box and the switch is a 3-way which when it is up it's on house power but when it's down it's on the pig tail for generator.
[ August 24, 2004, 09:23 PM: Message edited by: hurk27 ]
pappysparks
Member
Re: FAU QUESTION???
He probably has a defective trans in the furnace,ask him to check the secondary voltage from the trans..normaly it should be near 24 volts
He probably has a defective trans in the furnace,ask him to check the secondary voltage from the trans..normaly it should be near 24 volts
Re: FAU QUESTION???
joeyman,
Some of the newer furnaces with the diagnostic boards have a diagnostic code that indicates reverse polarity either at the transformer primary or secondary. Now I have seen where this code will appear many years after installation, after a board failure. The unit in question (Goodman/Janitrol) was in fact wired correctly for 7 years, the code was a malfunction of the board. Maybe he got a "reversed twinnings" code and is trying to blame you.
Brian
joeyman,
Some of the newer furnaces with the diagnostic boards have a diagnostic code that indicates reverse polarity either at the transformer primary or secondary. Now I have seen where this code will appear many years after installation, after a board failure. The unit in question (Goodman/Janitrol) was in fact wired correctly for 7 years, the code was a malfunction of the board. Maybe he got a "reversed twinnings" code and is trying to blame you.
Brian
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: FAU QUESTION???
But to say that it is causing the stat's to burn out? Thats a far cry. I just cant see this with a isolated power supply (24v 40ma) Somthing must be wired wrong on the low voltage side for this to happen if it's not a bad/wrong transformer.
But to say that it is causing the stat's to burn out? Thats a far cry. I just cant see this with a isolated power supply (24v 40ma) Somthing must be wired wrong on the low voltage side for this to happen if it's not a bad/wrong transformer.
A
a.wayne3@verizon.net
Guest
Re: FAU QUESTION???
Check the neutral connections.That simple thing has sent 240 through many circuits when a neutral is shared from circuits on 2 phases.
Check the neutral connections.That simple thing has sent 240 through many circuits when a neutral is shared from circuits on 2 phases.
Ed MacLaren
Senior Member
Re: FAU QUESTION???
If the low-voltage thermostat in question has a "heat anticipator", it can be burned open by some testing procedures. The heat anticipator element is designed to be in series with the contacts, and the load (relay coil, zone valve, etc) being switched.
I've seen many thermostats that have been ruined by inadvertantly shorting out the load while trying to test the relay by bypassing (shorting out) the thermostat contacts.
Ed
I wonder exactly what he means by "burning out"?
If the low-voltage thermostat in question has a "heat anticipator", it can be burned open by some testing procedures. The heat anticipator element is designed to be in series with the contacts, and the load (relay coil, zone valve, etc) being switched.
I've seen many thermostats that have been ruined by inadvertantly shorting out the load while trying to test the relay by bypassing (shorting out) the thermostat contacts.
Ed
- Status