Go Back  The Hull Truth - Boating and Fishing Forum > BOATING FORUMS > Dockside Chat
Reload this Page >

Testing White Rodgers Flame Sensor

Notices

Testing White Rodgers Flame Sensor

Old 11-14-2015, 08:10 AM
  #1  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Oct 2010
Location: Weymouth, Ma.
Posts: 2,019
Default Testing White Rodgers Flame Sensor

Model 3098-156 in small Weil McLain CGM gas boiler. Pilot is out and suspect bad flame sensor. Any way to test before buying new one, about $150. Just want make sure first. Thanks
hottoddie is offline  
Old 11-15-2015, 03:54 AM
  #2  
Senior Member
 
Join Date: Jul 2010
Location: Coastal South Carolina
Posts: 2,872
Default

can they be cleaned (do they rust?)
edwardh1 is online now  
Old 11-15-2015, 04:07 AM
  #3  
Senior Member
 
Join Date: Mar 2006
Location: Northern Lower Michigan
Posts: 2,540
Default

If you're talking about a standard flame rod that sits in direct contact with the burner flame...........yes..........they are easily cleaned.
Just remove it and polish it up with some 400 grit paper, fine steel wool or even scrape it lightly with a knife.

But before you do that tell me what your boiler is doing.
s_ebels is offline  
Old 11-15-2015, 04:21 AM
  #4  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Oct 2010
Location: Weymouth, Ma.
Posts: 2,019
Default

A few weeks ago I turned up the thermostat to get some heat and nothing. Checked for pilot flame and it was out. Just removed the flame sensor yesterday am but wanted to test it first. Easy to clean and reinstall so it's [probably worth a try. This part of the house has Jotul gas fireplace with fan that does a nice job so the Weil McClain is actually the secondary heat source.
hottoddie is offline  
Old 11-15-2015, 05:58 AM
  #5  
Admirals Club Admiral's Club Member
 
Join Date: Nov 2008
Location: Somewhere in the middle of Michigan
Posts: 10,369
Default

Yes, you can test a flame sensor. You'll use a DC current meter with a 200 microamp scale and 0.1 microamp resolution.

The flame sensor wire is connected to the controller. Disconnect the wire, connect one lead of the meter to the wire and the other to the controller terminal. Start the flame, observe the DC current on the meter. A good flame sensor typically produces 5-10 microamps of current. Your White Rogers may have different specs, so see if you can find them.

Edit- looks like the White Rogers you have is different than the flame sensors I'm talking about.
yarcraft91 is offline  
Old 11-15-2015, 06:56 AM
  #6  
Admirals Club Admiral's Club Member
 
Join Date: Nov 2008
Location: Somewhere in the middle of Michigan
Posts: 10,369
Default

It appears the OP's flame sensor is a mercury capillary device with a relay controlled by the sensor. The relay has 3 terminals- #4 (Common), #2 (hot and N/O) and #3 (cold and N/C). Here's how I would test it.

With the pilot flame and power off, remove the relay from its socket and use a multimeter to confirm continuity between terminals 4 and 3. Then, attach the meter leads to terminals 2 and 4, confirm no continuity. Start the pilot flame, within 60 seconds there should be continuity between 2 and 4. If not, the flame sensor system is probably faulty.
yarcraft91 is offline  
Old 11-15-2015, 01:00 PM
  #7  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Oct 2010
Location: Weymouth, Ma.
Posts: 2,019
Default

Yes it is a mercury capillary device. I will reinstall and check as you suggest in the next couple of days and report back. Thanks.
hottoddie is offline  
Old 11-20-2015, 06:11 AM
  #8  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Oct 2010
Location: Weymouth, Ma.
Posts: 2,019
Default

Flame sensor bench tests OK. Cleaned it up, reinstalled and pilot would not light after several attempts. Suspect failed gas valve. Opinions?
hottoddie is offline  
Old 11-20-2015, 07:38 AM
  #9  
Senior MemberCaptains Club Member
 
Join Date: Feb 2002
Location: North East
Posts: 5,938
Default

I am no expert but have replaced flame rods before. Last year I had the same problem as you with the pilot light and it turned out to be the valve. Sometimes you can get lucky when they stick and you can unstick them. I was not, had to have mine replaced.
FireFly is offline  
Old 11-20-2015, 07:46 AM
  #10  
Senior Member
 
Join Date: Mar 2011
Location: Cape Fear, NC
Posts: 11,460
Default

Definitely troubleshoot your valve like firefly, sounds like it.
back at it is offline  
Old 11-20-2015, 08:49 AM
  #11  
Senior Member
 
Join Date: Sep 2009
Location: Near Wheeling W.V.
Posts: 928
Default

Originally Posted by hottoddie View Post
Flame sensor bench tests OK. Cleaned it up, reinstalled and pilot would not light after several attempts. Suspect failed gas valve. Opinions?
Just to clarify, you are setting the dial to pilot and pushing or depressing it while attempting to light it up?
Bamby is offline  
Old 11-20-2015, 11:29 AM
  #12  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Oct 2010
Location: Weymouth, Ma.
Posts: 2,019
Default

Originally Posted by Bamby View Post
Just to clarify, you are setting the dial to pilot and pushing or depressing it while attempting to light it up?
Yes that is correct. Several attempts to make sure the small gas line purged but still no go. Even tried tapping the valve lightly with a hammer.
hottoddie is offline  
Old 11-20-2015, 11:39 AM
  #13  
Admirals Club Admiral's Club Member
 
Join Date: Jun 2009
Location: Amongst the FL fishies
Posts: 6,658
Default

Boo-o-o-om!!!!
airbrush is online now  
Old 11-20-2015, 11:44 AM
  #14  
Senior Member
 
Join Date: Jan 2013
Location: On the beach
Posts: 2,840
Default

Have you verified good gas supply?
Still Stoked is offline  
Old 11-20-2015, 11:46 AM
  #15  
Senior Member
 
Join Date: Sep 2009
Location: Near Wheeling W.V.
Posts: 928
Default

Page 23 here shows a replacement natural gas orifice available. Since it is removable and replaceable I'd pull it and see if it's plugged up with a bit of dirt or rust, clean and replace it.
Bamby is offline  
Old 11-22-2015, 01:27 PM
  #16  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Oct 2010
Location: Weymouth, Ma.
Posts: 2,019
Default

Today the pilot would light using a lighter. Then the main burner would light when I turned the gas valve on with the thermostat calling for heat. However after the main burner shut down the spark ignition would not relight the pilot which in turn would not fire the main burner. I now assume the problem is with the spark ignition system, either the high voltage transformer or the spark igniter itself. Any way check either or both?
hottoddie is offline  
Old 11-22-2015, 01:49 PM
  #17  
Senior Member
 
Join Date: Feb 2002
Location: NJ & MV
Posts: 3,793
Default

Originally Posted by hottoddie View Post
Today the pilot would light using a lighter. Then the main burner would light when I turned the gas valve on with the thermostat calling for heat. However after the main burner shut down the spark ignition would not relight the pilot which in turn would not fire the main burner. I now assume the problem is with the spark ignition system, either the high voltage transformer or the spark igniter itself. Any way check either or both?
Have you used a brass brush to to clean any scale off the sensor?

Also, a sign that the sensor has scale would be yellow flames after ignition.
No expert but this was explained to me by a technician, when I had problem. Maybe others more qualified might correct me if I'm m wrong and may not be applicable to all sensors.
aubv is offline  
Old 11-22-2015, 03:31 PM
  #18  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Oct 2010
Location: Weymouth, Ma.
Posts: 2,019
Default

Yes I cleaned the sensor with brass brush and 500 grit paper. It is very clean and bench tested OK. Right now the problem is no spark from the spark igniter that lights the pilot that in turn light the main burner, This is my first experience with spark ignition that lights a pilot that then lights the main burner. Seems redundant but that's what it is. I think if the spark problem is fixed then the boiler will work fine. Thankfully I have the Jotul gas stove to heat the area of the house until the problem is resolved. The WM boiler is now used as the back up heat source. I think the DV Jotul stove is more efficient than the WM boiler anyway.
hottoddie is offline  
Old 11-22-2015, 03:39 PM
  #19  
Senior Member
 
Join Date: Feb 2002
Location: NJ & MV
Posts: 3,793
Default

Originally Posted by hottoddie View Post
Yes I cleaned the sensor with brass brush and 500 grit paper. It is very clean and bench tested OK. Right now the problem is no spark from the spark igniter that lights the pilot that in turn light the main burner, This is my first experience with spark ignition that lights a pilot that then lights the main burner. Seems redundant but that's what it is. I think if the spark problem is fixed then the boiler will work fine. Thankfully I have the Jotul gas stove to heat the area of the house until the problem is resolved. The WM boiler is now used as the back up heat source. I think the DV Jotul stove is more efficient than the WM boiler anyway.
The pilot light housing on mine, has two flat surfaces that also need to be wire brushed on occasion.
aubv is offline  
Old 11-22-2015, 03:55 PM
  #20  
Senior Member
 
Join Date: Aug 2009
Location: Bright Side of the Moon
Posts: 3,500
Default

Check the ground connections and make sure they are clean and tight. Is there a spark that doesn't light the pilot or no spark at all?
Mine Now is offline  

Thread Tools
Search this Thread