I have a Janitrol warm-air furnce which we fitted with a 3 ton cooling coil to cool our downstairs HVAC zone, which is 1200 square feet in Oakland, CA. The heating component works just fine, but the cooling has always been very weak. It seems as though there should be a higher speed on the fan to push more air through in the cooling mode, but I can't find anything about it in the literature. Does anyone know if this is usually the case? Isn't there usually a way to set the blower speed on a furnace higher?

Any guidance would be greatly appreciated.