Solar Control Unit
The Goldline GL-30 differential temperature control is designed to provide maximum operating efficiency and flexibility to effectively manage today's innovative solar energy systems. It is a continuation of the advanced electronic technology which produced the popular C-30 and CM-30 controllers - standards of the solar industry since 1975, with hundreds of thousands of units installed worldwide. With an adjustable high limit of 50º-104ºF, the GL-30 is capable of handling most differential temperature control functions for operation of domestic water heating and sophisticated space heating and cooling. The GL-30 is designed to control recirculation, drain-back and closed loop systems.
Replacement unit for CM30 and C30:
• Control does not include power cord or sensors [must be purchased separately or in a package]
• Two SB-10K sensors may be required. [sold separately]
NOTE: TD-GL & DIX-30 Temperature Displays are discontinued
Three highly visible LEDs show:
• Power to control
• Power out from control
• Power out from control due to a recirculation mode to protect
• the system from freeze damage.
The GL-30 output is rated at 20 Amps and is designed to directly
operate a pump or fan for heat collection when the controller is sensing an appropriate temperature differential.
The GL-30 has an adjustable differential with a range of 8º to 24ºF. Solar systems with long pipe runs normally require a higher
turn-on differential temperature, and open loop systems with short pipe runs usually require a lower turn-on differential temperature for optimum performance. The GL-30 offers versatility to tailor controls to numerous specific systems designs.
Storage High Limit
The GL-30 allows you to set a high limit storage temperature from 110º to 230ºF.
Recirculation Freeze Protection
Recirculation freeze protection, when enabled, turns the GL-30
output on to circulate warmer storage water through the collectors when near freezing temperatures are reached at the collector sensor.
System Test Switch
The system test switch manually switches the GL-30 to ON, AUTO,
or OFF for complete control over the system at all times.
Product Application: Solar Domestic Water Heating System
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A complete typical solar domestic water heating system components and layout is shown below.
• Differential temperature control
• 8-20ºF adjustable turn-on differential
• 4ºF fixed turn-off differential
• 110-230ºF adjustable high limit
• 120/240 VAC input
• 20A, 2HP output
• Input power: 120 VAC or 240 VAC
• Output: SPDT powered contacts 1HP@115VAC, 2HP@240VAC
• rating @ 240VAC: 20A on NO contacts ; 10A on NC contacts
• Differential: 8/4 to 24/4°F
• High Limit: 110° to 230° F
• Environment: 15° to 130° F; 0 to 95% rH
• Accuracy: +/- 1°F
• Dimensions: 5.875" x 4.875" x 2.375"
• Temperature Sensors: Thermistor 10k @ 25°C/77°F not included
View the following manual for installation and troubleshooting
Download » Product Installation Manual
Download » Goldline Warranty
General Control and Sensor Trouble-Shooting Tips:
All of the GoldLine (formally Independent Energy) controls (including C30, CM30, G30 and GL30 series) and some of the Heliotrope General (HG) DTT series controls incorporated the use of 10k sensors. Some of the earlier HG controls and some other lesser known brands used 3k sensors.
To determine the type of sensor, the resistance must be measured in ohms (using a volt/ohm meter) when the sensor is at 77 degrees F. 10k measures 10,000 ohms and 3k measures 3,000 ohms. As the temperature goes up, the resistance goes down.
Resistance can be checked at any temperature, and then
convert the ohm reading measured to the temperature equivalent
by using the conversion chart.
Sensors can be purchased at
Water Heaters Parts and Supplies
Product Manufacturer: Goldline Controls Inc.
Product Warranty: 10 Year Limited Warranty
Goldline Controls Inc. now offers a full 10 year limited
warranty on all solar controls and accessories! This warranty
will cover repair or replacement of the control at no cost for
the first 24 months. For years 3 through 5, the repair/
replacement fee will be a maximum of 25% of the current list
price, and for years 6 through 10, the repair/replacement fee
will be a maximum of 50% of the current list price. The best
controls now have the best warranty. See the Goldline
warranty statement for detail.
Processing and Delivery Information: Please allow Processing Time as stated above for your order, plus standard transportation delivery time. Orders placed after 2PM EST may not begin processing until the next business day. Please call for Rush Processing and/or Rush Shipping options.