Upon arrival, system was locked out on code 7 for excessive limit circuit trips. Hooked up manometer for gas pressure and thermometers for entering and leaving temperature. Initial fireoff in low stage showed manifold gas pressure at 1.8inwc with 90F temperature rise, while specifications list 1.3-1.7inwc manifold pressureand 30-60F temperaturerise. Increased to high stage and high stage pressure is at 3.8inwc with 80F temperature rise, while specifications list 3.2-3.8inwc a d 40-70F temperature rise. Adjusted manifold gas pressures to bottom end of specifications, 1.3inwc for low stage, and 3.2inwc for high stage. During operation test for both stages it is noted that while the temperature rise is within range for both stages, 55F for low stage and 65F for high stage, the new Merv 14 air filter causes a high amount of restriction on airflow, also contributing to higher temperature rise. Merv 11 is the highest recommended Merv rating. Due to the inability to adjust airflow on this fur
