Heat&Glo SLR-D Cosmo IPI Pilot Won't Light

[SantasPants]

Hi. I have a Heat&Glo SLR-D Cosmo (manual) with an IPI pilot. The pilot makes a spark, but won't actually light. The fireplace was installed in 2016 and we're the first home owner in 2021 (house was empty for 5 years). The fireplace didn't light for the inspector and has never lit for us either. The fireplace is NG and horizontally vented right behind the wall it's mounted on. The outside temperature during winter when I try to use it is typically between 0-10 C (32-50 F). Some troubleshooting steps I've taken are:

• Pilot lights fine if I open the glass front for a few minutes (it won't light right away). Will continue lighting fine until it cools off
• Pilot won't light with a lighter
• Pilot lights fine if I cover the exterior exhaust with a bag
• I've hung some shredded tissue infront of the pilot, and while there is a draft with the glass open, there is no draft with the glass closed (at least not enough to move the tissue)
• Pilot won't light with a steel mixing bowl on top to block any possible draft from the top
• Pilot won't light with a shield to mostly block a draft from the bottom (see pictures), even with the mixing bowl on top too
• Spark gap looks good, about 3mm

I called a reputable company to take a look. The tech said the gas pressure was set too high, and a ground wire was loose. But sure enough the next day after it cooled off, it still won't light. The tech found the AC junction box sitting below the unit (see picture) and said it could be used to convert it to an always on pilot (which is a solution I would be happy with at this point), but to me it just looks like an AC splitter and the manual has no instructions for converting to always on. The ignition module doesn't appear to have any switch to change from IPI to continuous mode. There is no remote, just two decora wall switches for the gas and pilot.

The fact that it won't light with a lighter leads me to believe the ignitor is fine and it's more likely something to do with the pilot's gas supply, which maybe resolves when the unit is warmed up a bit by taking the front glass off? I'm also stumped why covering the exhaust with a bag makes it light instantly, but shielding the pilot doesn't seem to do anything. Any ideas and suggestions are welcome. If anyone knows of a compatible ignitor module (SRV593-592) which has a continuous pilot setting I'd be happy with that solution too.

Thanks for your help!

Pilot area without bottom shield. It's fully open on the front side:

Pilot with shield on the front side:

Two small gaps still on the back. Hard to fit a shield in without taking the whole thing apart, so I haven't done so:

Junction box the tech said can somehow be used to convert to a continuous pilot:

 

[Millbilly]

Does your fireplace have a continuous pilot mode?

 

[SantasPants]

After some searching I found that Heat&Glo does have a "Cabin Kit" available which essentially adds a switch and relay to support continuous pilot mode. But it's meant to address cold start issues in cold climates, and meanwhile my fireplace wont light at 12C/53F which isn't that cold. So I want to try finding some other underlying issue before doing this workaround.

After further testing I don't believe there is actually any gas coming out of the pilot (ex it can't be lit with a lighter) until the glass has been removed for a few mins. I found an Intellifire troubleshooting guide and it appears the control module is outputting over 0.98v required to activate the pilot solenoid, the pilot solenoid resistance tests correctly at 37 ohms, and the solenoid can be activated with an external power supply. The valve and pilot appear to be unobstructed as I was able to blow some air through with the solenoid activated. But this is with the unit all opened up and of course I already know it lights fine after the glass is removed for a few mins. Unfortunately I can't access the parts to test everything with the fireplace closed up. I ordered a new control module to try replacing first as it appears to be the most likely failure point despite it appearing to test ok. If that doesn't work I might resort to the cabin kit.

 

[Millbilly]

Are you running this on batteries? Can you show a picture of the control valve and control module

 

[Millbilly]

Air in system, weak spark, ignitor and flame sensor mixed up, failed control valve, pressure issue, pilot set too low. On some systems your voltage to pilot solenoid should be higher to open and then lower maintainance voltage. More pics would be helpful.

 

[SantasPants]

It's plugged in with a 3VAC adapter, but it also supports batteries and it has the same issue testing with batteries. I will open it up again on the weekend when the new control module comes in, but its the 593-500 valve and 593-592 control module. I don't believe the pilot on this valve is adjustable. The pilot voltage is supposed to be 1.05V at first (min 0.98 to activate the solenoid) then it's supposed to drop to 0.49 after it's lit, according to the troubleshooting guide. I tested it at 1.3V so it should be high enough. Probably not weak spark as manually lighting with a lighter doesn't work either. Could be air in the system, but I assume if I make enough attempts to light it should purge and light eventually which isn't the case. It only lights if I remove the glass for several minutes, or cover the outside vent with a bag. Then the pilot and main burner light no problem.

 

[Millbilly]

If you have good gas pressure into the valve and you have good voltage to the orange and you have no gas coming out of the pilot then you likely have a bad control valve. You can try tapping it with a wrench. With the glass off hold a flame to the pilot..even if there is air built up you can see the pressure pushing the flame

 

[SantasPants]

Tapping doesn't work. When holding a lighter, there is no air movement. At least, not until the glass is off for 5 mins then it works fine. I removed the pilot solenoid from the valve and tested it with 1.5V and it activated no problem, and I was able to blow air through the valve inlet and out the pilot. So I have a control module outputting the correct voltage and a working pilot valve, but only when disassembled. I am not sure how to test if the solenoid is opening when it's all together with the glass on as the sound is too low to hear. So without any other theories I will try replacing the control module, then the power adapter, then maybe the valve. If that doesn't work then I can install the cabin kit. This is an expensive approach though so it would be better to know the actual problem.

 

[Millbilly]

I don't think this has anything to do with your venting or glass. Those issues are more of a problem for your main burner flame if there is a venting issue. Maybe the installer put in a propane unit by mistake and your pilot orifice is too small? Im still going with control valve given all your readings

 

[SantasPants]

Yeah, given the temperature shouldn't be low enough to cause cold start issues it probably is the valve or control module. Just some weird issue that the tests don't expose. Just one of those issues that can only be addressed by process of elimination I guess. If I replace those and it still doesn't work, maybe I'll wait until summer to see if it lights then which would at least confirm it's a cold start issue and the cabin kit is actually the required fix. We're basically past winter now anyways so it's too late to use it this season anyway!

 

[Millbilly]

Like I said I don't think cold start is even a consideration.. your pilot should light even if your flu is cold and it's not even that cold. If your valve is getting voltage, and you have gas pressure to the valve, and gas is not coming out of the pilot. Then I'd replace the valve