Heatilator Gas Fireplace Intellifire Ignition Problem

[Chris5601]

Hello. I'm new to this forum, so please forgive me if I'm asking a question that has already been answered. I searched the forum and couldn't find an answer to my question. I have a Heatilator Novus gas fireplace (Model NDV4236I) that was installed in 2009. I've used it very little over the years and not at all for the last several years. I recently tried to start it up again, and I'm having a problem with the Intellifire ignition. The fireplace wouldn't start when I turned on the wall switch, so I followed the troubleshooting guide in the user manual. The symptom I identified in the user manual is, "Pilot won't light, there is no noise or spark."

Here's what I've done:

1. Checked voltage at switched outlet located under firebox. Voltage is 120V AC.
2. Checked voltage of transformer at spade connectors on control module (Dexan Industries Wiring GM-6KA) with module fully connected. Voltage is 3.28V AC.
3. Visually inspected all wiring connections, including module ground wire. All appear to be good. (Haven't checked continuity of each individual wire yet.)
4. Removed ignitor wire from control module and grounded I terminal on module. This created a spark, but not every time.
5. Thought this might mean a bad control module, so ordered a replacement, but replacement wouldn't spark at all. Replacement was same module but was labeled RevB - original module isn't labeled RevB.
6. Connected everything back up with original control module, and ignition worked, but not sure it's going to continue working.

So my problem seems to be that the control module is working intermittently. (I don't have batteries in the backup power source that's wired into the system.) I'm thinking I should check continuity of each individual wire, but I'm not sure how to do this. I have a basic multimeter. Can anyone please provide instructions on how to check continuity? Also, any suggestions on what else I should try?

Thanks!

 

[DAKSY]

Is the spark going to ground before it gets to the igniter in the pilot assembly?
It could be arcing thru cracked igniter wire sheathing below the burner, or
the ceramic encasing the igniter could be compromised...

 

[Chris5601]

Thanks for your response!

To update my previous post, I tried to restart the fireplace this morning, and it was back to the ignitor not sparking when I shorted from the ignitor terminal on the control module to ground. I figured out how to check continuity with my multimeter, so I checked continuity of all seven wires in the wiring harness that connects to the control module, and they're all continuous. I also checked continuity of the ignitor and sensor wires from the control module to their tips at the pilot assembly, and they're both continuous too. Does the continuity check of the ignitor and sensor wires rule out the problem you suggested of the spark going to ground before it reaches the pilot assembly?

I read a troubleshooting guide for my control module that I found online. It suggests mostly the same troubleshooting steps as my owners manual, but it also indicates that the control module can become "locked out". How would this happen, and how would I unlock it? I can find instructions to unlock a control module that has the remote control feature, but mine doesn't have remote control. I'm wondering if I'm somehow causing the module to lock out and then accidentally unlocking it without knowing what I'm doing. This might explain why the problem is intermittent.

I'm also wondering if I'm operating my wall switches incorrectly. I have two wall switches for the fireplace. One controls the 120V power to the power outlets installed under the firebox. The other connects to the switch wires in the wiring harness that connects to the control module. I've been turning both switches on and off at the same time to try to turn the fireplace on and off. It seems like I could just leave the 120V power switch on all the time and just operate the other one when I wan to turn the fireplace on and off. Could the way I'm operating the wall switches be causing a problem?

Finally, as I mentioned in my original post, I bought a new control module because I thought the intermittent nature of my problem could mean my control module was bad or going bad. The new module didn't spark at all when I installed it. The new module is labeled RevB (with a sticker on it). The original module isn't labeled RevB. Could the different version of the new module be causing it not to work at all?

Any suggestions would be much appreciated.

Thanks!

 

[DAKSY]

Hmmm. First of all, the install instructions for your fireplace indicate
that it is to be connected to UNSWITCHED 120VAC.
So turn that switch on & leave it on.
Secondly, take a look at the OTHER wall switch.
Pull it & pull the Tstat wires off of it.
Check the wires & the switch for continuity.
I've seen wall switches go bad, & when they do they
cause intermittent outages & starting problems..
Another way to check the switch is to jump the switch wires together.
If the fireplace comes on & stays on, the switch is the culprit.

 

[Chris5601]

DAKSY, I owe you one! It was the wall switch. I checked continuity of the switch wires, and they were good. I checked continuity of the switch and it was iffy - fine one time and not the next. The fireplace started up just fine when I shorted the switch wires to each other. So, I replaced the switch, and the fireplace is working great again. I'll keep the 120V AC switch on all the time as you recommended and just operate the other one. Thank you very much for your advice!

 

[kc2cag]

DAKSY, I owe you one! It was the wall switch. I checked continuity of the switch wires, and they were good. I checked continuity of the switch and it was iffy - fine one time and not the next. The fireplace started up just fine when I shorted the switch wires to each other. So, I replaced the switch, and the fireplace is working great again. I'll keep the 120V AC switch on all the time as you recommended and just operate the other one. Thank you very much for your advice!

Exactly same problem here! After troubleshooting as much as I could at the fireplace, I removed the wall switch and checked the resistance across the terminals. With the switch off, resistance was infinite. With the switch on, the resistance varied from infiite to a few ohms. I rapidly opened and closed the switch a number of times, and the pilot lit, so I apparently "cleaned" the contacts a bit by the rapid switching. Next step is to get a new switch.

This could also explain a mystery from the last heating season: The flames would randomly cut off, and cut back on fairly quickly. Not what I would expect from an "overheat" condition. The poor contact in the switch may have been the culprit.