HPC Fire · Installation
How to Load Lava Rock + Glass on an HPC Burner (and why over-loading triggers Code 2)
Too much lava rock or fire glass on an HPC burner causes an Over-Temperature (Code 2) fault AND chokes the flame pattern. HPC's spec: use #657 standard lava rock as a base coat and any larger rock or decorative glass as a top coat only. Here's how to do that right the first time.
By Ash · Updated November 10, 2026
What you need
- HPC Standard Lava Rock #657 (base coat)
- Decorative media of choice (large lava, fire glass, ceramic logs) — top coat only
- Disposable gloves
Step by step
Lay the #657 base coat first
Pour the standard HPC lava rock (#657) directly onto the burner plate. Fill to just cover the burner surface — about 1/2 inch deep. The small rock fills the air gaps around the burner holes so flame distribution is even.
Add larger lava or glass as top coat only
Over the #657 base, scatter your decorative media. Larger lava chunks, colored fire glass, or ceramic logs can go here — their job is cosmetic, not structural. Keep the TOTAL depth to about 1 inch over the burner surface. Spread any excess outward toward the edges of the pan, not up over the burner.
Confirm the air-mix is in the right position
Below the burner plate there's an air-mix fixture with six holes. For Liquid Propane (LP): the fixture must be CLOSED over those six holes. For Natural Gas (NG): it must be OPEN. Install it wrong and the flame will burn yellow and sooty on LP (starved) or too lean on NG.
Test the pattern on first light
First light will purge the gas line of air — expect a 1-2 second delay before flame. Once lit, inspect the flame pattern around the whole burner. Dead spots, concentrated towers, or yellow tips mean the media loading is interfering. Shut off, adjust media distribution, try again.
Common mistakes
- Loading large lava as the ONLY media. Without the #657 base, large chunks sit directly on the burner and block individual holes. You'll see random dead spots and uneven flame. Every HPC burner specs a base + top coat two-layer loading.
- Loading 3+ inches of media "to hide the burner". HPC's cap is 1 inch over the burner surface. Deeper traps unburned gas (Code 2 risk) and chokes the flame cosmetically — you'll have less visible fire, not more.
Hands-on tips
- Buy more #657 than you think you need — it compacts over the first few burns and you'll want to top up.
- Fire glass looks dramatic but fragments can crack from thermal shock. Replace broken pieces immediately so sharp edges don't catch fingers.
- Take a photo of the as-loaded burner on first install — if flame pattern changes later, the photo tells you if media shifted.
Questions people ask
Can I mix fire glass and lava rock?
Yes — fire glass as the top coat over the #657 lava base is a popular combination. Keep total depth at 1 inch max.
Does the media need to be replaced on a schedule?
#657 base rock lasts years with no maintenance. Fire glass can crack from thermal cycling — replace fragmented pieces annually.
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