Joseph, item M in that pdf addresses it pretty well. If they still have a problem, they can contact HL Tech Services for ideas. Depending on the unit, they may be able to extend the venting to the edge of the deck and power vent it. As it is, it would appear to fail item M for a 12" clearance. Practically speaking, exhausting 500F+ heat into that homemade grille is asking for a new definition of deck BBQ.

If they need a local resource for repairs, they can contact me or FireSide Hearth & Home up in Limerick, Pa. This is not a warrantied item so it would fall onto the homeowner and contractor who did this.

On a more practical point, this unit will probably experience intermittent deoxygenation and sooting as the deck traps flue gases then recirculates them back into the Fp. The air intake for the Fp is the passageway closer to the house while the exhaust is out at the tip of the trapezoid.

Kevin, I can assure you significant CO and water vapor are produced.

Nice location for that condenser, too!

HTH,
Bob

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Keep the fire in the fireplace.