Geo-Booster

The Geo‐Booster is an active loop pressurization system that eliminates issues with low loop pressures in closed‐loop geothermal ground loop or hydronic systems. The Geo‐Booster will maintain a minimum loop pressure of 35 psig on the system. The Geo‐Booster includes a pump with a built‐in pressure switch factory set at 35 psig, and a check valve to prevent back‐flow into the one‐gallon reservoir (tank). The sealing cap ensures a closed system, prevents loop fluid evaporation, and provides vacuum relief allowing the fluid to be pumped from the reservoir.

Installing the Geo‐Booster during the initial ground loop installation on new systems will eliminate the need for a technician to return to a jobsite to ‘bump’ the system pressure and will ensure zero low loop pressure callbacks. Since the tank can be filled with pre‐mixed loop fluid it eliminates the worry of diluting the antifreeze and lowering the freeze protection in the loop. The Geo‐Booster system is also perfect for existing closed‐loop geothermal systems that have reoccurring issues with low loop pressure.

The Geo‐Booster will maintain a minimum of 35 psig on the ground loop system but the system pressure can be higher. For example, during the cooling season the ground loop temperatures rise causing the HDPE loop pipe to slightly expand lowering system pressure. The Geo‐Booster will ensure that the pressure does not fall below 35 psig. During heating season the loop temperature drops and the loop pipe contacts slightly raising the loop system pressure over the 35 psig set pressure of the Geo‐Booster. This is a completely normal and expected process.

Yes, this is a perfect application for the Geo‐Booster system. The HDPE pipe used in the ground loop expands and contacts with seasonal loop fluid temperature changes. Since the pipe is not perfectly elastic it relaxes over time leading to a loss of system pressure. Large ground loops such as slinky loops, pond loops, and large horizontal and vertical loops use more pipe and therefore are subject to greater loop expansion and pressure loss than smaller systems.

No. The system includes a check valve preventing back‐flow into the Geo‐Booster’s pump and tank. In addition, the pump has an interior, built‐in check valve.

Yes. The Geo‐Booster includes an isolation ball valve that can be used to isolate the unit during service. In addition, the Booster contains a check valve preventing back pressure from harming the pump or tank.

The Geo‐Booster can be mounted in any available indoor location in or around the mechanical room. The Geo‐Booster includes over nine feet of hose which allows flexibility in locating the system. If the unit needs to be located further than nine feet from the plumbing access point additional hose can be added or alternative pumping methods can be employed provided that the materials are compatible with the antifreeze used in the loop. The Geo‐Booster can be plumbed into any point of the loop but is preferably located at the lowest pressure point in the system which is normally the return pipe from the ground loop just before the circulator pump(s). Please see the installation instructions for further details.

There is no limitation on ground loop size for the Geo‐Booster. However, if the Geo‐Booster is installed on a very large loop system the tank will require more frequent checks to be sure it contains loop fluid.

The Booster’s tank is never under pressure (other than static fluid head pressure). Fluid is pumped from the tank into the loop system. The tank is protected from pressurization or back‐pressure by a check valve.

Even if the tank is emptied the pump should not force air into the ground loop system. The diaphragm pump does a good job of pumping liquid but not air. However, if the tank is empty the pump will continue to run. This serves as a reminder to fill the tank with fluid. Note that if the tank is emptied the hose should be purged of any trapped air prior to return the unit to service as is done in an initial system start up (see installation instructions).

The tank holds 1 gallon of loop fluid.

Yes. The pump automatically shuts off when the pressure reaches 35 psig.

Field installation of the system reported measurements of 0.09A at 122Vac during operation.

Yes, but it requires modifying the Geo‐Booster to include a float switch and relays. This is unnecessary for the majority of installations.

Yes; the power supply is rated for 85‐264Vac single phase input.

Installing an expansion tank in a geothermal ground loop system provides additional fluid capacity which helps prevent low loop pressures. The Geo‐Booster can be used in place of an expansion tank or in addition to an expansion tank. Installing an expansion tank along with a Geo‐Booster provides added fluid capacity.

During typical system operation the pump will only run for a few seconds to boost the system’s pressure to 35 psig.

No. Ethanol and methanol are flammable when not sufficiently diluted with water. Injecting pure glycol will not allow for sufficient mixing with the water/loop fluid present in the loop.

Yes. However, this method requires that you monitor your system pressure and add additional water to the loop when the pressure drops to an unacceptable level. This method does not allow a technician to measure the amount of water they add to the loop and will slightly dilute the antifreeze mix in the loop. In some areas with poor water quality the loop is filled with better quality water (plus antifreeze where applicable) from an off‐site location. In these areas ‘bumping’ the pressure with the local water source could cause problems with components in the ground‐source heat pump system.

The Geo‐Booster allows you to monitor the exact amount of fluid that is being added to the loop and allows you to inject an antifreeze solution into the loop. Water make‐up systems use a domestic water source and there is no easy, inexpensive way to monitor the amount of water injected into the loop. Therefore, the antifreeze solution can be diluted possibly leading to damage to the geothermal heat pump. Also, water‐make up systems are required to have backflow preventers to prevent contamination to the drinking water supply. In many areas these devices require annual inspection and certification.

Non‐pressurized flow centers are designed for use with specific circulators (pumps) that do not require a high level of net positive suction head (i.e. low NPSHr) and cannot be used for all pump types. Every pump has a certain level of required inlet pressure (called NPSHr) that is specified by the pump’s manufacturer. Since many pumps have a higher NPSHr than can be realistically achieved by a standing column of water non‐pressurized systems cannot be universally used. In addition, non‐pressurized flow centers have many limitations including:

• Limited installation locations (distance below the loop field or heat pump) and orientation (flow center tank must remain vertical). Difficult to install in a crawlspace or attic.
• Larger size requires more space for installation.
• Water level decrease in the flow center tank (standing column) reduces the positive suction head pressure on the pump increasing the chance of pump cavitation and pump failure.
• In general, cannot be installed in series or parallel.
• Requires more field plumbing connections than pressurized flow centers increasing field labor and the chance of leaks.
• Flush/purge valves not incorporated (in some manufacture’s systems) so they must be field fabricated and/or installed.
• Requires additional ball valves to be field installed to isolate the heat pump from the ground loop (on some manufacture’s systems). For more information on pressurized versus non‐pressurized flow centers, see FAQs for Geo‐Prime.

No. If the loop installer/contractor flushed the loop properly using an industry standard flush cart there should be no air bubbles present in the closed loop system. However, if there is a small amount of air trapped in the loop the Geo‐Booster will help keep the air bubbles very small due to the minimum 35 psig pressure level. Without a Geo‐Booster, small air bubble that may be trapped in the loop at 60 psig will become large air bubbles at 5 psig. These large air pockets can ‘lock’ a section of ground loop causing it cease functioning, air‐lock a pump leading to loop pump failure, or cause noise as the air passes through the loop pump.