Goldline GL-235 User Manual

GL-235

Solar Pool Controller

Installation & Operation Manual

G

LD

C

LINE

ONTROLS

www.goldlinecontrols.com

Description

The GL-235 is a differential temperature control for solar heating of pools, spas, and hot tubs. It provides
differential temperature control with an adjustable, calibrated water temperature high limit. Automatic
nocturnal cooling (for pools that overheat in hot climates) and recirculate freeze protection functions can
be enabled/disabled via internal jumpers.

Input power can be either 115 or 240 VAC. The output controls a 24VAC automatic valve actuator. For
older systems with 12VAC valves, an internal jumper can be moved to select 12VAC output operation. The
GL-235 also has a high voltage output for controlling a filter pump or booster pump.

Specifications

Power: 105-130VAC, .5A 50/60Hz.

or

195-250VAC, .3A 50/60Hz

Output: Selectable low voltage 24VAC,

20VA, .85A or 12VAC, 20VA,

1.7A

SPST-NO isolated contact
115VAC 1HP
240VAC 2HP

Sensors: 2 required (thermistor,
10Kohm @ 25C/77ºF).

Differential: on at 4ºF, off at 1.5ºF

Desired
Pool
Temp.: 70-104ºF calibrated scale or So-

lar Off, 75 (24ºC) -104ºF (40ºC)
on some models

Recirculate
freeze: On at <40ºF (4.5ºC), off at > 42ºF

(5.5ºC), Enabled via jumper

Nocturnal
cooling: On when collector 8ºF less than

pool and pool hotter than limit,
off when collector 3ºF less than
pool or pool cooler than high limit.
Enabled via jumper

Installation

Mounting

The GL-235 is designed for outdoor use. Mount the box vertically with the knockouts facing downward.
For safety, the GL-235 must be a minimum of 5 feet (horizontally) from the pool or spa.

Power input

Turn off power at circuit breaker before wiring. Remove the internal panel to expose the wiring connections.
Either 115VAC or 240VAC can be used. Refer to the input wiring diagram (Figure 1) on next page.

WARNING: Applying 240VAC to the 120VAC input terminals will cause permanent damage to the
control.

Grounding

Refer to NEC and local codes for specific grounding requirements. In general, a separate ground conductor
must be run to the ground terminal on the pool service panel.

Low Voltage (LV) output: Solar Valve

The GL-235 controls a single valve. In most applications this is the solar valve, which diverts water through
the collector panels or through the normal pool loop depending on conditions.

2

All controls are shipped with the output voltage set to the industry standard 24VAC. To use the GL-235

g

with older 12VAC valves, move jumper J4, located on the right side of the circuit board.

The GL-235 provides two different types of connections to the pool/spa actuators. For older actuators with
no wire end connector, a 3 position terminal block is used. Connect the wires to the proper terminal block
according to the color code shown in Figure 4. If the valve operates opposite to the way it is supposed to,
reverse the red and white wires. Be careful not to short the valve output wiring. The GL-235 is fused and
shorting the output will require replacing the fuse.

For newer Goldline, Compool, Hayward, and Jandy actuators (with wire end connectors), two 3-pin
connectors are supplied. Plug the actuator into one of the two 3 pin connectors as shown in figures 2 or

3. If the valve operates opposite to the way it is supposed to, disconnect and plug into the other connector.

High Voltage (HV) output: Booster Pump

The GL-235 can control a high voltage booster pump in addition to the normal low voltage solar valve. Note
the high voltage relay contacts are isolated so that the booster pump can be run on a separate circuit, as
required by many local codes. The GL-235 turns on, the valve output will operate first, and then the HV
relay will operate 30 seconds later.

High Voltage (HV) output: Timeclock Override

The GL-235 can also be used to override the filter pump timer. This is very important if recirculate freeze
protection or nocturnal cooling functions are being used. Also, this function can be used on systems where
the system should operate whenever solar heat is available, regardless of the timer settings. The HV relay
will operate approximately 30 seconds after the LV relay.

Sensor Mounting and Wiring

Most installations use a PC sensor to measure the pool temperature and another PC sensor to measure the
solar temperature. Alternatively, an SC-¼ sensor can be screwed into the pump strainer basket to measure
the pool temperature.

Pool Sensor: Drill a 3/8” (or 5/16”) hole in the PVC pipe. Remove burrs around the hole. Check that the
O-ring is seated on the PC sensor and then insert sensor into pipe. Tighten hose clamp over the sensor to
make a seal—DO NOT OVERTIGHTEN.

Solar Sensor: Use a screw or silicon adhesive to attach the sensor near the solar collector array. The sensor
does not have to be attached to the collectors. It is only important that the sensor be exposed to the same
sunlight as the collectors. Additionally, the underside of the sensing element may be covered with silicon
to minimize wind cooling.

Other 10K ohm Goldline sensors may be substituted. Wire should be twisted pair 20A WG. Sensor wiring
run outdoors must be rated for outdoor use and ensure that the wire connections are protected from the
weather. Do NOT run sensor wir es in the same conduit or multiconductor cable as the valve actua-
tor wires or any 120/240V circuit. For long runs or runs near other electrical wiring use shielded cable
(Belden 8428 for outdoor use). Ground the shields to the GL-35/LV ground screw.

EARTH

GROUND

240 VAC

input power

high

voltage

output

{

EARTH

GROUND

115 VAC

input power

high

volta

output

{

e

Figure 1

3

Freeze Protection

If you are relying on the collectors naturally draining to provide freeze protection, it is very important that
you use a non-positive seal valve or drill a hole (1/8"--1/4") in the diverter of a positive seal valve to
allow the collectors to drain. Alternatively, the GL-235 control can provide recirculate freeze protection.
If enabled, when the GL-235 senses a freeze condition at the collector sensor, it will allow circulation of
relatively warm water from the pool to the collector panels.

The GL-235 will allow recirculation when the collector temperature falls below 40ºF and will stop
circulation when the collector temperature rises above 42ºF. While this type of freeze protection has proven
to be adequate in relatively mild climates, it is extremely important that the sensors be properly placed and
that the homeowner realize that the system is unprotected in the event of a power failure. Recirculate freeze
protection is NOT recommended in climates where freezing temperatures are common or last for extended
periods.

Goldline strongly recommends the use of GC-3 freeze snap switches if freeze protection is being utilized.
Snap switches should be wired in series with the collector sensor. Placement of the snap switches at the
coldest point of the collector array and exposed plumbing will help assure that freeze protection starts early
enough to protect the system.

The GL-235 is shipped from the factory with recirculate freeze protection disabled (the jumper is present
but installed on one pin only). To activate recirculate freeze protection, install the jumper across both pins
marked “RECIRC”, located near the top right of the main circuit board.

If recirculate freeze protection is to be used on a GL-235, either:

•

The filter pump must be set for continuous operation or

•

The GL235 High Voltage Output must be wired for Timer Override function.

Nocturnal Cooling

The GL-235 has nocturnal cooling logic, which can be enabled/disabled via a jumper on the main circuit
board. During nighttime hours, when enabled, the GL-235 will circulate relatively warmer water from the
pool to the collector panels, thus cooling the pool over time. The GL-235 will circulate water when the
collector temperature AND the pool temperature is hotter than the high limit setting. Circulation will stop
when the collector temperature is 3ºF less than the pool temperature OR the pool temperature is cooler than
the high limit setting. The GL-235 is shipped from the factory with nocturnal cooling disabled (the jumper
is present but installed on one pin only). To activate nocturnal cooling, install the jumper provided onto the
two pins marked “COOLING” located near the top right of the main circuit board.

If nocturnal cooling is to be used, either:

•

The filter pump must be set for continuous operation or

•

The GL-235 High Voltage Output must be wired for Timer Override function.

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