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IN007 Rev
J
1.4 GROUND WATER
Under no circumstances should water be allowed to be drawn into the inlet of the HS Series Fan as this
may result in damage to the unit. The HS Series Fan should be mounted at least 5 feet above the slab
penetration to minimize the risk of filling the HS Series Fan with water in installations with occasional
high water tables.
In the event that a temporary high water table results in water at or above slab level, water will be
drawn into the riser pipes thus blocking air flow to the HS Series Fan. The lack of cooling air will result
in the HS Series Fan cycling on and off as the internal temperature rises above the thermal cutoff and
falls upon shutoff. Should this condition arise, it is recommended that the HS Series Fan be
disconnected until the water recedes allowing for return to normal operation.
1.5 CONDENSATION & DRAINAGE
(WARNING!:
Failure to provide adequate drainage for condensation can result in system failure and
damage the HS Series Fan).
Condensation is formed in the piping of a mitigation system when the air in the piping is chilled below
its dew point. This can occur at points where the system piping goes through unheated space such as an
attic, garage or outside. The system design must provide a means for water to drain back to a slab hole
to remove the condensation.
The use of small diameter piping in a system increases the speed at which the air moves. The speed of
the air can pull water uphill and at sufficient velocity it can actually move water vertically up the side
walls of the pipe. This has the potential of creating a problem in the negative pressure (inlet) side
piping. For HS Series Fan inlet piping, the following table provides the minimum recommended pipe
diameters as well as minimum pitch under several system conditions. Use this chart to size piping for a
system.
Pipe
Diam.
Minimum Rise per Foot of Run*
@ 25 CFM
@ 50 CFM
@ 100 CFM
4"
1/32 "
3/32 "
3/8 "
3"
1/8 "
3/8 "
1 1/2 "
*Typical operational flow rates:
HS3000, or HS5000
20 - 40 CFM
HS2000
50
-
90
CFM
All exhaust piping should be 2" PVC.
Run
Rise
