DIY Home Improvement, Remodeling & Repair Forum

DIY Home Improvement, Remodeling & Repair Forum (http://www.houserepairtalk.com/forum.php)
-   HVAC (http://www.houserepairtalk.com/f8/)
-   -   Faulty Valve Controller (http://www.houserepairtalk.com/f8/faulty-valve-controller-8004/)

seamaj 11-18-2009 02:40 PM

Faulty Valve Controller
 
Hello,

I seem to be having a problem with my gas furnace, and I am just debating wether or not this is something I can do, or if I should call a professional.
I do have an inclination for electrical, plumbing, and other house repairs so I am comfortable with doing repairs.
The problem I am having is, my digital thermostat says that the heat is on, but when I check the unit in my basement, itdoesn't fire up. The pilot is running just fine, but no gas going to the rest of the unit. So, from process of elimination, I took the cover off the gas regulator (Im not sure what it is actually called) and used a slot screwdriver to switch it to on, and it fires up no problem.
When I try to use the thermostat to turn it off (after I manually turned it on) it doesn't work either.
So, I am thinking that it is probably the valve controller.
I am going to try just replacing the digital thermostat, but in the meantime, is there any advise or ideas out there that someone can suggest?
It is a honetwell control unit, and a very old furnace. I would put the model numbers up, but I am at work currently, and will post them when I can if they are needed.

Thanks

travelover 11-18-2009 04:57 PM

I'd try a new thermocouple before I bought a new thermostat. If the thermocouple doesn't sense a flame ('cause it is defective), the gas valve will not open.

kok328 11-18-2009 07:09 PM

Travelover is correct and with no prior history of the thermostat being a problem, I too would suspect a bad thermocoupler. However, verify that 24VAC is being sent to the heat circuit (white wire) from the transformer (red wire) via the thermostat. If you have 24VAC from ground or common to the white wire when "calling for heat", then the thermostat is working.

seamaj 11-18-2009 07:39 PM

Thanks, where would this part be located
 
Ok. This is some good information.
After looking at some images on google, I suspect that this thermocoupler would be located comming out of the gas valve, and place above or beside the flame above the flue? I did see this a metal tube-like piece comming out of the gas valve and it is closed off at the end, located kinda to the side of the flame?

I appreciate the advice...

travelover 11-19-2009 05:49 AM

Quote:

Originally Posted by seamaj (Post 36911)
Ok. This is some good information.
After looking at some images on google, I suspect that this thermocoupler would be located comming out of the gas valve, and place above or beside the flame above the flue? I did see this a metal tube-like piece comming out of the gas valve and it is closed off at the end, located kinda to the side of the flame?

I appreciate the advice...

yes, the thermocouple should be a copper cylinder located within the pilot flame envelope. It is attached to the gas valve by a thin copper tube. You can buy them at big box stores - they are a universal part.

seamaj 11-19-2009 09:33 AM

3 Attachment(s)
Quote:

Originally Posted by travelover (Post 36919)
yes, the thermocouple should be a copper cylinder located within the pilot flame envelope. It is attached to the gas valve by a thin copper tube. You can buy them at big box stores - they are a universal part.

I tried to look for a copper cylinder, but all I could find was a metal type one. Here are a couple of pictures of the unit.
There is what appears to be a copper cable attached to the envelope, but it is covered, so I am not 100% on that one.

Thanks

seamaj 11-21-2009 04:06 PM

Update
 
Just thought I would post an update to what I've found.

This unit is not compatible with "univeral" thermocouples.
This is a very specific unit, and I guess I will have to do a little more searching to find what I need. It actually connects via a wire from the gas valve directly to the stay on pilot. I am not sure where I am going to find this, I may just have to purchase a new furnace all together. This unit is a Honeywell CS 82 that I guess were made back in the 60's. This unit has worked very well for me since I purchased the home 2 1/2 years ago.

Thanks.

travelover 11-21-2009 06:11 PM

Sorry to hear that. The photo looks unlike anything that I have experience with, but I'd suggest doing some on line research on that furnace model and or the valve model to see if parts are available. It seems likely that you can fix it for much less than replacing it.

mikeysab 11-28-2009 10:28 PM

Okay, I'm at my wits end with my heater, and I can't help but to post my problem here. If anyone can help, it would be greatly appreciated. I've spent hundreds of dollars on repairmen that have done nothing. I've had thermocouples replaced many times, and nothing helps. I can't pay for the "professionals" anymore, and figured this would be a better place to seek help. So here's the issue:

Pilot won't stay lit, and now I can't get it lit at all. I've had it lit, but it usually only lasts for about 3 days. My neighbor looked at it (he has the same unit, as do all my neighbors) and messed around with the flame rollout switch. I've pressed in the button on the flame rollout switch and got it to light, but the pilot just blew out. The unit is a Laars jvs 75c, which I believe was changed from electric ignition to pilot. Could this be a faulty flame rollout switch, or a wiring problem, or a faulty gas valve? I really need help with this one, because it's alaready cost me close to a thousand dollars, and I've gotten nothing accomoplished. Someone please help me with this problem.

Jeffthrow 11-26-2010 12:23 PM

I have the same exact problem, seems the switch to light the pilot(on Honeywell gas valve) may be failing me. Been acting up for a while now, when I depress the switch everything fires up flawlessly.. I turn the switch to on and no matter how long or little I hold it in, entire system powers down. After much research and studying of what i have (thermocouple, ignighter, and pilot seem to perform great. The Pilot switch? seems to be very loose as if its tripped off.
Basically i can clamp switch in the on posision, depressed slightly furnace and thermostat run flawlessly but obviously do not think running it this way is safe so I do not.. sometimes I can get it to work for days after holding it down forever and releasing ever so carefully.. sick of the cold nights and times are tight to make a worthless payment to a pro to troubleshoot for days on what I know works fine.
Can this be Fixed by opening up the gas valve, common problem??


All times are GMT -6. The time now is 06:54 AM.