I've been working on two Healtilator GC 300 gas fireplaces located on the 11 th floor of a downtown hotel. Both have developed chronic pilot outages, and I've observed one of them being blown out by a puff of wind when weather conditions have been normal with no untoward winds, although in this exposed location there are always going to be winds of some kind.
This fireplace is the same as the Healtilato GC 100 except it has two sealed glass windows on opposite side of the fireplace, while the GC 100 has one. It was built in 12/96 and has a robertshaw pilot burner, millivolt gas valve and a temperature limit switch connected between one side of the pilot generator and the ground lug of the gas valve.
There is no evidence of any problems with the limit switch (negligible voltage drop), and plenty of voltage to operate the gas valve.
I thoroughly disassembled the pilot burner and cleaned out the Robertshaw pilot burner and orifice. The problem continues.
These fireplaces have a rubber gasket that tends to crack and deteriorate --- these are in better condition than many, although there is a small piece cracked off that breaks the integrity of the gasket.
This is a direct vent fireplace with the supply and combustion gasses taken and vented outside through a factory termination kit.
I've observed a similar problem with GC 100 fireplaces located atop a high condominium in an exposed location. In that case, someone had built a small sheet metal hood to offer protection to the pilot burner. When I removed that hood, the fireplace had pilot outage problems. When I reinstalled it, the problems disappeared. I can't recall the condition of the gasket in those fireplace, since the possibility of the problem being the gasket hadn't occurred to me.
Normally I'd expect this kind of sealed system not to be susceptible to wind, especially with pilot outages every hour or so on days with little wind. Winds ought to affect the inlet and outlet portions of the termination caps in identical ways, minimizing breezes through the fireplace when it is sealed.
With the glass off, there is a noticable cold air breeze through the fireplace. I'm wondering if the damaged gasket is the cause of the problem since it unseals the system and may allow air and wind to flow through the fireplace in ways that wouldn't happen if it were completely sealed.
Apparently this is a problem which has developed over the past 2-3 years, and didn't exist for a number of years after the equipment was originally installed.
Any comments or theories on what might be going on are invited.