Author Topic: distance between water heater and furnace?  (Read 957 times)

Offline playatwork007

  • Pro Tech™
  • *****
  • Posts: 12
distance between water heater and furnace?
« on: January 25, 2019, 08:02:42 AM »
What is the minimum distance between water heater and furnace?

What is the minimum distance between the furnace and the basement wall vapour barrier? 1 inch?

Offline Admin

  • Administrator
  • *****
  • Posts: 2350
    • HVAC TECH GROUP
Re: distance between water heater and furnace?
« Reply #1 on: January 25, 2019, 12:01:55 PM »
Clause 4.14.2 says an appliance needs 24" clearance where service could be necessary.

In the B149.1-10, Clause 7.26.5 said a direct vent water heater requires 36" clearance on the burner side.  This Clause is not found in the B149.1-15 so it can be ignored when installing appliances after July 1, 2017.

Check the furnace manual for the clearances but most will say the back of the furnace requires 0" clearance.

Offline Porcupinepuffer

  • Pro Tech™
  • *****
  • Posts: 456
Re: distance between water heater and furnace?
« Reply #2 on: January 26, 2019, 07:50:35 AM »
I often see them right up close to each other. It's that front service clearance of 24" for each appliance that's really important. Most furnaces are zero around the 3 sides. In terms of clearance to wall vapour barrier, it depends on what you're talking about with the furnace. It's probably 0 in the furnace manual, but almost always at least 1" from the supply plenum.

Offline Admin

  • Administrator
  • *****
  • Posts: 2350
    • HVAC TECH GROUP
Re: distance between water heater and furnace?
« Reply #3 on: January 26, 2019, 08:21:52 AM »
Good point about the plenum. On the furnaces I install the plenum would only be 9/16” inside the edge of the furnace casing so the furnace should be kept away from the wall slightly.

Offline jhazen

  • ***
  • Posts: 1
Re: distance between water heater and furnace?
« Reply #4 on: February 10, 2019, 07:02:50 PM »
Great site.

Is the clearance to the front of a furnace 24", 30" or 36"?  I'm finishing a basement and don't want to make the furnace room wall too close to the existing furnace or on demand hot water heater that mounted on an exterior wall. 

Offline Admin

  • Administrator
  • *****
  • Posts: 2350
    • HVAC TECH GROUP
Re: distance between water heater and furnace?
« Reply #5 on: February 10, 2019, 07:20:04 PM »
You need 24” clearance to the front of each appliance.

Quote
4.14.2 - An appliance shall be installed with a minimum service clearance of 24 in (610 mm) to any side, top, or bottom where service could be necessary, except where
(a) a greater distance is indicated on the appliance rating plate; or
(b) the distance is not sufficient for the removal, replacement, or repair of a component, an accessory, or any equipment either forming an integral part of the appliance or connected to the appliance, in which case minimum service clearance that is adequate to effect such removal, replacement, or repair shall be provided.
All measurements shall be taken between the outermost projection of the appliance and surrounding structure or property line after the appliance has been installed.

Quote
4.14.4 - A clear and unobstructed passageway at least 36 in (900 mm) high and 36 in (900 mm) wide shall be provided to each appliance.