Raypak 106 Installation & Operating Instructions Manual page 15

If there is any possibility of back-siphoning when the
pump stops, it is recommended that a check valve (or
valves) also be installed in the system.
Internal Automatic Bypass Valve
A built-in automatic bypass valve is provided in the
In/Out header. The internal bypass valve automatical-
ly responds to changes in water pressure in the piping
system. The proper amount of water flow is maintained
through the heater under varying pressures dictated
by the conditions of the pump and filter.
Bypass Disc
Spring
Fig. 12: Internal Automatic Bypass Valve
External Auxiliary Bypass Valve
An auxiliary bypass valve must be used when flow
rates exceed 70 GPM (265 LPM). Usually a high-per-
formance pump size larger than one horsepower will
exceed this flow rate. This valve is required to comple-
ment 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
Full Port
Ball Valve
or Globe
To Pool/Spa
Bypass Valve
Fig. 13: Auxiliary Bypass Valve
Bypass Body
Valve
From
Pool/Spa
NOTE: Do not use a gate valve as an auxiliary
bypass valve.
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 comfort-
able to the touch. If pipe is hot, close bypass; if cold,
open bypass.
Pressure Relief Valve Installation
To conform to local building codes, it may be neces-
sary to install a pressure relief valve. A 3/4" (1.9 cm)
pressure relief valve, having a capacity equal to or
greater than the BTUH input of the heater to be
installed, is recommended for this heater. The maxi-
mum pressure relief valve setting is 125 psi (862 kPa).
This relief valve needs to be installed on the outlet pipe
from the header as noted in Fig. 14 below.
PIPE ONTO DISCHARGE SIDE OF PIPING
Fig. 14: Pressure Relief Valve Installed
If required, this needs to be installed in a field-supplied
fitting external to the heater. The valve shall be
installed in a vertical position. Do not over-tighten.
Install the pressure relief valve hand tight plus 1/2 turn.
WARNING: To avoid water damage or scalding due
to relief 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.
The valve lever should be tripped at least once a year
to ensure that waterways are clear. If the relief valve
does not function properly, replace it immediately.
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