17
Flow Rates
Companion Flange Connections
The inlet/outlet header flange accepts a 1-1/2" copper
tube or 1-1/4" galvanized pipe as a slip connection
directly into the manifold. The flange is also threaded
for 1-1/2" pipe thread. 1-1/2" CPVC adapters (when
available) can also be used.
DO NOT use petroleum base assembly fluids (such as
petroleum jelly or lubricating oil). If assembly lube is
required, use a silicone-based compound, such as
Amoral, etc.
Pipe Size
Min. gpm
Max. gpm
1-1/4”
20
60*
1-1/2”
20
60*
*When flow rates exceed 60 gpm, an external auxiliary bypass valve
is required. See External auxiliary bypass valve section for details.
Table E: Flow Rates
Inlet/Outlet Header
Flange Gasket
Header Flange
Pipe
Fig. 15: Header Connections
Automatic Chlorinators and
Chemical Feeders
All chemicals must be introduced and completely dilut-
ed into the pool or spa water before being circulated
through the heater. Do not place chlorine tablets or
bromine sticks in the skimmer. High chemical concen-
trations will result when the pump is not running (e.g.
overnight).
Chlorinators must feed downstream of the heater and
have an anti-siphoning device to prevent chemical
backup into the heater when the pump is shut-off.
Unitherm Governor Operation
The patented Unitherm Governor is a thermostatic
mixing valve specifically designed to maintain constant
heater internal temperature between 105 - 115°F
despite continually changing flow rates from the filter
and changing pool temperatures.
This narrow range is needed to prevent damaging
condensation on the burners which will occur if the
heater runs for any length of time below 100°F. It is
also needed to inhibit scale formation in the tubes by
maintaining temperatures well below accelerated scal-
ing temperatures.
CAUTION:
Never install PVC directly into header
flanges. The initial connection must be made with a
high temperature material such as CPVC or Copper.
For IID Pilots: PVC may be utilized immediately after
the initial connections. For Standing Pilots: Copper
or high temperature CPVC pipe and two elbows are
required between the heater and the PVC
connections (heat sinks not supplied).
NOTE:
High chemical concentration from feeders
and chlorinators that are out of adjustment will cause
very rapid corrosion to the heat exchanger in the
heaters. Such damage is not covered under the
warranty.
Outlet
Inlet
Unitherm
Governor
Fig. 16: Unitherm Governor Location
