We recently added a second furance on the first floor. The originel stayed upstairs and just capped off ductword to downstairs but had to reduce blower speed because it was blowing so hard. Now the new down stairs furnace (h9mpvo75f12a) does't blow hard enough. How should the dip switches be to increase blower? 1 & 2 are contin. 3,4,5 are for heating, 7, 8, 9, for cooling. Factory settings were all off. We have a 2 wire prog. Thermastat. Furnace has 1/2 hp dc motor.

You just do not flip the dip switches on those type of units since damage to the motor and control circuits can be caused. You need a manometer/pressure reading device so that the blower controls can be set within the allowable range for your unit. If you read the manual for your unit or service manual for your unit it will be explained there. It is better to be safe than sorry since this could also void the warranty on your new unit.

BTW I cannot find the model number you listed and you also failed to post the brand.

Sorry it is a tempstar here are some charts I attached from the manuel but they don't mean much to me

The contractor/installer ,if experanced with the brand should know what to do,and would not cause you to void the warranty

As mentioned in my previous post these adjustments need to be made by a professional with the proper tools. System damage can happen by the wrong adjustments without the proper tools.