19
BYPASS
PLUG & SHAFT
BYPASS SPRING
BYPASS VALVE
Figure 23. Internal Automatic Bypass Valve
5.10. External Auxiliary Bypass Valve
Where Required - An auxiliary bypass valve should
be used when flow rates exceed 125 GPM (473 lpm).
Usually a high-performance pump size larger than
two horsepower will exceed this flow rate. This valve is
required to complement the function of the automatic
bypass valve, particularly when starting the heater in
winter or early spring when the spa or pool temperature
is below 50°F (10°C). It also serves to eliminate needless
pressure drop through the heater and accompanying
reduction in the flow rate to the spa jets, etc.
FROM HEATER
TO HEATER
TO POOL/SPA
FROM POOL/SPA
FULL PORT
BALL VALVE
OR GLOBE
VALVE
BYPASS VALVE
Figure 24. Auxiliary Bypass Valve
5.11. Auxiliary Bypass Valve
Adjustment
To set bypass - With clean filter, adjustment is made by
feeling the inlet and outlet pipes at the heater. Outlet pipes
should be slightly warmer than inlet and comfortable to
the touch. If pipe is hot, close bypass; if cold, open bypass.
5.12. Pressure Relief Valve
Installation
To conform to local building codes, it may be necessary
to install a pressure relief valve. A 3/4" pressure relief
valve, having a capacity equal to the BTUH output of the
model to be installed, is recommended for this heater.
The maximum acceptable pressure relief valve setting is
125 psi.
PRV
Figure 25. Pressure Relief Valve
NOTE:
To avoid water damage or scalding due to valve
operation, drain pipe must be connected to valve outlet
and run to a safe place of discharge. Drain pipe must be the
same size as the valve discharge connection throughout
its entire length and must pitch downward from the valve.
No shut-off valve shall be installed between the relief
valve and the drain line. Valve lever should be tripped at
least once a year to ensure that waterways are clear.
5.13. Plumbing
5.13.1. Water Connection
The heater requires water flow and positive pressure to
fire and operate properly. It must therefore be installed
downstream of the discharge side of the filter pump.
See Figure 29 and Figure 30.
A typical installation is plumbed as follows:
1. The inlet side of the filter is plumbed directly to the
discharge side of the filter pump;
2. The outlet side of the filter is then plumbed to the
inlet of the heater; and
3. The outlet of the heater is plumbed to the return
line to the pool or spa. The pump, filter and heater
are thus plumbed in series (Salt generators and
chemical feeders must be down stream of the pool
heater).
