Clogged hole - no go! Blow it out for a happy customer.

Since 1980, all unvented heaters, including vent-free gas logs and alternative fires, have been equipped with Oxygen Depletion Sensor Pilots (ODS).  The designs of all makes of these calibrated pilots have a common feature and a common result:  they have a small hole or holes that draw air in to mix with the gas to make the pilot flame.  With the air is also dust and lint which accumulates over time.  Eventually, the accumulation becomes an obstruction which disrupts the proper operation of the pilot flame.  This is common to all vent-free gas log sets, not just Rasmussen Chillbuster or Alterna VF sets.

The typical symptoms that your customers will contact you about include: a) Unable or difficult to establish the pilot light; or
b) Pilot lights, but the burner(s) and/or pilot shuts down after a few minutes of operation.

Action to Take, either by the homeowner or by your service team on a paid call:
1) Gather tools needed:
a) Vacuum cleaner with brush attachment
b) A can of compressed air with a tube (the type that is used to clean computer keyboards) or a drinking straw.
2) Vacuum up all lint, dust & debris from logs, grate, burner(s), burner air intake and air shutter regions (underneath burner, where air gets drawn in), and pilot area. View photo of burners.

3) Using the compressed air or a straw, blow out:
a) Burner ports (where the main flame comes from); View photo of burners.
b) Burner air intake and air shutter regions (end of burner(s) where gas and air mix); View photo of burners.
c) Around the valve knob (the one you depress to light the pilot); and
d) MOST IMPORTANTLY, the air intake holes of the ODS Pilot Assembly.  These small air intake holes are between 1/16″ and 1/8″ in diameter and are located about 2” from the end of the pilot from where the pilot flame originates.  Use the compressed air or straw to blow out these holes.   Repeat a couple of times.

On some ODS, the top hole is covered by a thin metal strip.  Slightly lift the metal strip and point tube or straw directly into the hole and blow out several times.  Be careful not to permanently bend this strip when accessing the hole).

We recommend that customers perform this maintenance annually before the start of the heating season, more often if the symptoms reoccur.  This is a perfect opportunity for dealers to enter into a Seasonal Start-up Maintenance contract with their customers – cash flow!

Electronic Ignition Systems (EIS), also know as Intermittent Pilot Ignition Systems (IPI), are becoming ever more popular, for a variety of reasons. In some cases, it is because of mandates to not install standing pilot systems (usually in new construction installations). In others, consumers feel they are saving resources (both gas and money) by not having a constantly burning pilot (the payback from gas savings versus the cost of the EIS could be as much as twenty years). Another reason is characterized as that of safety, although it is really borne from the consumer’s inherent fear of gas, so they wish to have no open flames at all, no matter how small, when an appliance is unattended.

But regardless of the reason, the function of EIS/IPI systems is the same, and the service issues from which we receive calls mostly fall into two categories:

1. Ground not established; and
2. Sensor is not engulfed by pilot flame during operation.

1) Ground. The EIS system should be viewed as a circuit through which electricity flows. Starting at the control module, this is the path:

Control Module → Orange Electrode Wire → Electrode → Pilot Flame (yes, electricity flows through fire) → Pilot Hood → Pilot Bracket → Gas Log Burner → ** Ground ** → Control Valve → Wiring Harness → back to Control Module.

I’ll address the Pilot Flame in the next section. Establishing Ground can be as easy as scratching off some paint on the burner so that you have metal-to-metal contact between the pilot bracket and the gas log burner. It may be that you need to run a grounding wire from the pilot bracket to a source of ground, such as a gas line, or back to the control valve. Sometimes it’s a matter of trial and error. But regardless of how you achieve it, you must have good ground to complete the circuit.

2) Sensor Must be in the Pilot Flame. The EIS/IPI systems are what I term “Pilot on Demand” systems. When you flip the switch, it starts a lighting sequence, with continuous sparking that lights the pilot gas. The resulting flame must engulf the sensor electrode so that:

i. It competes the circuit (see above); and

ii. It “justifies” the pilot flame to the control module. When the pilot flame fully engulfs the electrode, it is essentially telling the control module that “Hey, we’ve got a flame that can light the main burner, so it’s okay to open the valve and let the gas flow to the main burner.”

If the pilot flame does not fully engulf the electrode, the control module will just keep on sparking, until it gets tired or finds the flame.

Proper positioning of EIS electrode in pilot flame. Note the cherry red color of the electrode tip.

If the EIS successfully completes the lighting sequence and lets gas flow to the main burner, but then later the main flame goes

out, it is because the pilot flame pulled away from the electrode. Causes of this could be:

1. Electrode just barely in adjustment at the edge of the pilot flame.
2. The pilot flame is influencing the pilot flame, pulling it away from the electrode.
3. Natural draw of the fireplace is pulling the pilot flame off of the electrode.
4. Wind has blown the pilot flame away from the electrode.

In the first case, the electrode needs to be adjusted so that it is fully engulfed in the pilot flame from the start. In the other cases, you may need to reposition the pilot and/or provide external shielding to remove flame or wind influence. In any case, the pilot must always fully engulf the electrode in order to provide smooth, continuous operation.

If the main burner flame cycles on and off repeatedly, it is due to the flame touching, then pulling away from the electrode.

Touch, then pull away; touch, then pull away. Correcting this situation is identical to the above paragraph. You must counteract the influences on the pilot flame so that it stays rock steady on the electrode.

The above situations reflect almost 99% of all service calls for EIS/IPI systems. Knowing what causes them is half the battle.  Establishing Ground, setting up the electrode in the correct position during the installation and making the proper adjustments and/or shielding makes up the last half.  And when one “fix” doesn’t correct the problem, try another, because “it ain’t over ’til it’s over.”