In my last 2 posts, we discussed condensate in 90+% efficient furnaces and the D.O.E. Rules that will go into effect May 1, 2013 for all furnaces. We discussed pH of the condensate and the possible need for acid neutralizer kits. We also discussed how much condensate is formed in a 90+% efficient furnace. The reason, again, for emphasis on 90+% furnaces is this will become the standard in ALL northern tier states on May 1, 2013.
What this means is that you cannot install anything less that a 90+% efficient furnace. Unlike transitions for A/C’s where you could use up your inventory and the restriction was only put on manufacturers and wholesalers not to sell them after a certain date, this says that you cannot install anything less that a 90+% efficient furnace — period!
So, this brings us to the question of venting. Existing chimneys will become obsolete. You can use an existing chimney as a chase to run the PVC vent pipes but only if there are no Catergory 1 appliances also being vented in to the chimney. If there are Category 1 appliances in the chimney it cannot also have PVC pipe vents in it also because they will melt from the heat of the Category 1 appliance(s). (As a side note — you will probably need to install a liner so the chimney is properly sized for the lesser input or you could have real condensation problems in the chimney without the furnace also in it.)
In anticipation of the new ruling, we have had our furnaces recertified to accommodate installations where there may be longer vents (such as condos &/or apartment complexes) and also made a change to allow some atypical vent configurations.
You will probably want to check with your individual wholesaler/manufacturer for their recommendations on venting, but York 90+% efficient furnaces can now be vented in either 2, 3, or 4 inch PVC. The new 4 inch allows us to vent up to 150 equivalent feet of both intake and vent pipe on a 2-pipe system or up to 150 equivalent feet of just vent pipe if you are doing a 1-pipe system and using combustion air from the space where the furnace is located.
When we talk about equivalent feet, we need to look at fittings, especially the type of elbows as they drastically affect the vent length. As you can see by the following table, there ARE different types of elbows. We always recommend the “sweep” els for the best performance and application.
Having these extended vent lengths should make it easier to properly vent the 90+% efficient furnaces in homes that used chimneys in the past.
We also have been certified to vent DOWN. This was never possible with 80% efficient furnaces but, since this is a Category 4 appliance, we can do just that. Here are the RULES you have to follow to do downward venting.
Application of this vent configuration may be very handy when you have a slate or clay tile roof and really can’t go up with your vent. Again, you will need to check with your wholesaler/manufacturer if you can do this with their product. This is approved for York 90+% efficient furnaces. The limitation is the maximum if 16 feet down and making sure you have a drain with a trap at the bottom to get ride of the condensate.
So, keep in mind you have until May 1, 2013 to use up your 80% efficient furnaces because you will not be able to install them after that date. Though there is nothing definite at this point, what I have heard is, “The published information talks about fines and whistle blowing rewards” if you are caught or turned in for installing anything less that a 90+% efficient furnace after May 1, 2013.
Hopefully, knowing there are venting procedures you can use to accommodate the new law, will help your move to the new efficiency standards easier.