14
Flex Fuel Owner’s Manual
March 2011
5: Installation
Expansion Tank
Since the Flex fuel is a non pressurized system, an expansion tank is needed to allow the water to
expand when heated.
The Expansion tank should be connected to the furnace through 1” line and should be placed higher
than the top of the furnace. (See Diagram On Page 11)
Your expansion tank should be sized according to the total amount of water in your system. for every 150
gallons of water in the system, there should be room for 5 gallons in the expansion tank. Do not over fill
your expansion tank as it may overflow when the water in the system heats up and expands.
Note: The expansion tank must be vented so that the system will not become pressurized.
There MUST NOT be a valve between the expansion tank and furnace. Failure to vent the furnace
may result to damage to the furnace and/or severe injury or death.
Expansion Tank Kit
The following images shows the basic layout for attaching the site tube and vent cap to your expansion
tank. Installation is the same for both the 10 and 20 gallon tanks. Ensure that the vent is properly used
and that the system is not allowed to become pressurized.
The Expansion tank must be placed higher than the top of the furnace. Ensure that the mounting
location is capable of supporting the weight of the tank plus the weight of the water when completely
full. The sight tube can be on either the right or left side of the expansion tank.
Horizontal Orientation
Expansion Tank (20 Gallon Shown)
0020-247
1” Blk St 90
0020-247
1” Blk St 90
0020-250
1” x 2” Blk nipple
0020-140
1” Pex x 1” MPT
1” Pex Line
1” Pex Line
1” Pex Line
0020-142
1” x 1” Pex
Crimp 90
0020-145
1” Pex Crimp
Ring
To Furnace
0020-273
Vent Cap
0020-145
1” Pex Crimp
Ring