Lennox Furnance going into Watchguard Mode! Help!


  #1  
Old 01-10-09, 11:31 AM
J
Member
Thread Starter
Join Date: Jan 2009
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
Unhappy Lennox Furnance going into Watchguard Mode! Help!

I have a Lennox G60DFV(X) gas furnace that is a downflow system. It is about 4 years old.

I am experiencing an intermittent problem with my furnace (ugh!).
Most of the time the furnace will operate normally, however, about 2 times per day, the furnace will enter into the Watchguard mode and shut itself off for 60 mins. Upon returning from the 60 minute shutdown period, the furnace will operate normally.

Here is how it gets to the Watchguard mode:
1) Thermostat calls for heat
2) Combustion Air Inducer turns on
3) delay
4) gas valve opens and ignitor lights flame
5) flame stays light for a few seconds, then gas valve closes (no more flame)
6) delay
7) gas valve opens again and ignitor lights flame,
8) flame stays light for a few seconds, then gas valve closes (no more flame)
9)....this gas/ignitor sequence happens for a total of 4 or 5 trys before the furnance enters the Watchguard mode.

I know it is entering the watchguard mode because I translated the status LEDs and timed until it returned to operation.

I checked the primary limit switch, closed
I checked the flame rollout switches, both closed

I haven't tried to clean the flame sensor yet or checked the pressure switches.

My air filter is clean and I always replace it every 3 months.

What baffles me the most is that this problem is intermittent and does not happen consistently.

Can anyone help me troubleshoot this? I am really close to calling someone who knows what they are doing, I just don't want to pay a lot of money for something simple...

I appreciate any feedback!
Joe - Canton, MI
 
  #2  
Old 01-10-09, 11:35 AM
J
Member
Thread Starter
Join Date: Jan 2009
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
More Info

Here are some more pieces of information that I have dug up:

The 2 status LEDs are alternating slow flash when the furnace shuts down after the iginition sequence.
I looked in the manual, this is what it says for alternating slow flash, "Watchguard -- burners failed to ignite OR limit open more than 3 minutes OR lost flame sense 5 times in one heating cycle OR pressure switch opened 5 times in one heating cycle"


When it enters Watchguard mode, I can cycle the primary power to the furnance and it will then operate normally.
 

Last edited by jgasiewi; 01-10-09 at 12:12 PM. Reason: additional info
  #3  
Old 01-12-09, 07:25 PM
J
Member
Thread Starter
Join Date: Jan 2009
Posts: 5
Upvotes: 0
Received 0 Upvotes on 0 Posts
Fixed (I think)

I took some advice and waited until I heard the furnace about to go into Watchguard mode. Just before it went into Watchguard mode, I watched the status LEDs and it showed a code that translated to "Low current output of flame sensor".

I removed the flame sensor and inspected it. It appeared to be fairly clean and in good shape, but I took some steel wool to it to clean it anyway.

I put it back into place and things have been working fine ever since. I am keeping my fingers crossed.

Seeing that I had the sensor out, I took down some numbers that I hope are going to translate into a replacement part number. I think I am going to find a replacement part just incase I need a backup. I have been told that these things only last about 5-8 years before they need replacing.

Joe
Now warm in Canton, MI.
 
  #4  
Old 01-12-09, 08:22 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 4,469
Upvotes: 0
Received 1 Upvote on 1 Post
I wouldn't bother with a spare for the flame sensor. If you clean it once/year, it will be fine.

Having a spare hot surface ignitor is worthwhile. I think that's the part you have heard fails --- which it is prone to do. It's also inexpensive, easy to diagnose as a problem and easy to replace (generally speaking) as long as you don't break it.

So getting one of those as a spare is a good idea.
 
  #5  
Old 01-23-09, 07:27 AM
B
Member
Join Date: Jan 2009
Location: Bellingham, WA
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Question

I have the same Lennox furnace with the same intermittent Watchguard mode issues. I'd like to try Michigan Joe's suggestion of removing the flame sensor, inspecting it and cleaning it, but have no experience inside the workings of my furnace. Is this doable for the average handy type person? The furnace is only three years old and was routinely serviced last year, so I'd prefer to avoid another costly service call if possible. Thanks,
-Bea
 
  #6  
Old 01-23-09, 07:52 AM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 4,469
Upvotes: 0
Received 1 Upvote on 1 Post
Hey Bambi---


Starting a new thread is recommended. It rapidly gets confusing to try to deal with more than one problem on a thread.
 
  #7  
Old 01-23-09, 09:11 AM
E
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
Originally Posted by bhambea
....removing the flame sensor, inspecting it and cleaning it, .....Is this doable for the average handy type person?
Yes. Usually held in place by some fairly accessible screw. On some furnaces it's easier to get to than others, but always doable.

The furnace is only three years old and was routinely serviced last year, so I'd prefer to avoid another costly service call if possible.
If you don't mind, what all did they do, and what did you have to pay?
 
  #8  
Old 01-02-12, 07:44 PM
L
Member
Join Date: Jan 2012
Location: USA
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Joe - had the same issue, in Canton also!
Cleaned the flame sensor with steel wool and it is now working.

Thanks!
 
  #9  
Old 02-11-12, 07:50 AM
J
Member
Join Date: Feb 2012
Location: USA
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Cleaning the Flame Sensor worked for me too!!!
Thanks
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: