1. Remove old furnace

• Disconnect any electrical, gas, ducting, plenum transitions, return drops, and venting from the existing system. 

• Discard any old gas connectors and flue connectors. 

• At no time can pre-made CSST gas connectors be used more than once. 

• If the new equipment is the same size as the old, you may be able to re-use the ducting. So carefully disassemble it. 

2. Install furnace

• Furnaces can be installed in many different positions. 

• Refer to steps 2a-2c for your type.

2a. Scenario 1- Free standing

• Set the furnace in a spot the will give the straightest transition into the supply plenum whether it is vertical or horizontal. 

• If the unit is sitting on the floor, it is preferred that the new unit is set upon vibration pads rather than directly on the floor. 

• For downflow configurations that are sitting on a combustible surface, ensure a manufacturer-approved non-combustible floor base is used. 

2b. Scenario 2- Hung furnace

• If the unit is hung from the ceiling or rafters, use the all-thread and unistrut in a way that the front of the unit will not be obstructed. 

• Ensure all cabinet clearances to combustibles as well as access clearances that are required by manufacturer specifications and local codes are followed. 

• Consider vibration isolation when practical. 

2c. Scenario 3- Garage installation

• If the furnace is installed in a garage, make sure the source of ignition is no less than 18" above the floor surface. 

3. Install filter box

• Whether installing the filter box on the side of the cabinet or the bottom, it is highly recommended that a 4-5" thick media filter is used whenever possible.

•  A minimum MERV 6 filter is required. 

• The filter box should be designed in a way that will not allow air to bypass the filter. 

• Filters shall never be installed inside of the furnace cabinet. 

4. Connect ducting

• Connect supply ducting to the supply outlet of the furnace and the return ducting to the filter box with sheet metal fittings. 

• Use S-cleats and drives to secure any duct seams. 

• Where the duct meets the equipment, use a 1/2" single or double lip to give a good rigid & tight connection. 

• If possible, use a flexible duct connector. 

• Mechanically fasten any seams where drives are not used (S-cleats only) and where the duct meets the unit. 

• Use a minimum thickness of 26ga sheet metal for any transitions. 

• Fiberboard or Thermo-pan shall never be used on a duct system.

5. Sealing duct

• All ducting must be sealed with mastic. Reference the "Air Seal Duct" section of this manual. 

• Ducting that meets the furnace or filter box can be sealed with silicone as long as the connection is a snug fit. If not, seal with foil-faced butyl tape.

6. Reconnect gas

• Reconnect gas with approved materials & methods according to the IFGC and Dominion Energy Good Practices book. 

• A rigid gas pipe must be used to exit the furnace cabinet before any CSST, or pre-made gas flex connectors are used. 

• Always install a new approved gas shut off valve. 

7. Test for gas leaks

• After new gas connections are installed, test all connections for gas leaks with an combustible gas detector at the rate of 1 inch per second. 

• If a leak is detected, verify it with a soapy solution. Tighten fittings that leak and re-test. 

8. Reconnect electrical

• A licensed electrical contractor must do this work. 

• It is required that all furnaces have a service switch installed within 6' and in direct sight of the appliance if one doesn't already exist.

9. Determine  intake & vent termination locations

• At all times, the intake will be run to draw outside air. Never draw air from the CAZ. 

• Vent and intake termination clearances shall be in accordance with the manufacture specifications, RMGA, and local building codes.

10. Install venting

• Size the venting according to manufacturer specifications for the BTU size and length equivalent. 

• Venting shall be sloped back towards the furnace when possible. 

• All joints shall be sealed with a 2-part glue and contrasting primer. 

• Support PVC piping at a minimum of 4' intervals for horizontal runs and a minimum of 10' for vertical runs. 

11. Install condensation drain line

• Follow manufacture specifications for connecting condensation drain to the unit. 

• Run the condensation line to a drain or condensate pump and discharge in an approved method. 

• If the condensation line runs along the floor surface, it shall be in PVC and secured to prevent disconnection or damage.

• If the furnace is outside the condition space, the drain line and pump need to be insulated in a way to prevent freezing. 

12. Test

• Adjust fan speed, to ensure the heat rise and static pressure fall within the manufacturer specifications. 

• Perform a combustion analysis and make necessary adjusts to the orifice size based on your duration calculation or gas pressure, so the flue gas measurements fall within the ranges listed on the "New Furnace Install Checklist." 

• At no time can you peen orifices on the furnace. Orifices must be replaced with new ones that are the proper size. 

• Complete the "New Furnace Install Checklist" and place it in the client's file. 

13. Place Green Sticker

• Fill out and place the Dominion Green Sticker on the door of the furnace. 

• Fill out and place the WAP orange filter sticker on the ducting where it is easily noticeable. 

14. Leave a spare filter

• Leave at least one additional spare filter with the client. 

15. Client education

• Use the Furnace Client Ed Checklist to educate client on the new furnace.  

16. Worst Case Draft Test

• Conduct a Worst Case Draft Test to verify Category I, II and III appliances are venting safely before leaving home for the day. 

• Testing shall be recorded using the WAP Worst Case Draft Test from. 

17. RMGA

• Work must be done by a RMGA Certified Technician

18. Manual J

• All furnaces must be sized correctly to the home they are being installed per Manual J based on post-retrofit dwelling characteristics. (SWS 5.0108.4a)

19. Codes and Specs

• Equipment must be installed according to manufacturer specifications and local codes.