Greetings everyone, I am a new member of this community. Last August, we upgraded our community water system with a Franklin Electric Subdrive ConnectPlus, serving 27 homes for various purposes including home use and outdoor lawn watering during the summer. The system features a 7.5 hp motor located at 60 feet in a 218 ft well. Previously, we had a traditional setup with a 60-40 contact switch. We were informed that the pump would adjust its speed based on demand. During startup, the system reaches a maximum of 60hz with a 19.8 amp draw, then maintains a range of 53-58 hz with an 18.3-18.8 amp draw under normal use. The pump never fully ramps down when idle, only resting when reaching the higher end of the spectrum for a short period. The VFD is currently set at 60-50psi. My concern is whether the system should slow down during low demand and shut off at that point, rather than at the higher end. Could the transducer being located in the pumphouse instead of the pressure tank house be causing the system to linger on the high end without slowing down? During periods of low demand, it would be expected for the motor speed to drop to the low 40s with amperage levels around 14-16. At present, the only noticeable advantage of the system is the soft start feature, as it behaves similar to a traditional setup.
While I do not have personal experience with this specific hardware, I have extensive knowledge of pressure control systems and three-phase pump motors in the water industry. Based on information gathered from the Franklin Electric website, the SubDrive Utilityâ„¢ Variable Frequency Drives offer a constant pressure solution for various types of systems including single-phase, two-wire, and three-phase systems. Your system may have either a single-phase or three-phase pump. If it is not three-phase, it may not provide optimal speed control below 50Hz. There are two pressure sensor options available - an analog (4 to 20mA) pressure transducer or an adjustable pressure switch. The placement of the sensor in the hydraulic system could slightly affect performance. Typically, a drive designed for constant pressure will enter "sleep" mode once the pressure setpoint is met and the drive has ramped down to the "sleep" frequency. This may also occur if the pressure setpoint has been maintained for a certain period of time regardless of the VFD output frequency. Manuals detailing the setup process and specifications for your installation can be downloaded from the Franklin Electric website for further verification.
OkiePC mentioned that although they do not have direct experience with this specific hardware, they have extensive experience in the water industry dealing with pressure controls and various types of drives, especially 3-phase pump motors. As per information gathered from the Franklin Water website, the SubDrive Utility™ Variable Frequency Drives offer a consistent pressure solution for single-phase, two-wire systems, as well as three-wire and three-phase systems. Depending on your system, you may have either a single-phase or three-phase pump. In cases of non-three-phase systems, achieving precise speed control below 50Hz may be challenging. Additionally, there are two pressure sensor options available – an analog (4 to 20mA) pressure transducer or an adjustable pressure switch. Placing the sensor further downstream in the hydraulic system could slightly impact performance. Typically, a drive configured for constant pressure will enter a "sleep" mode once the pressure setpoint is met and the drive has ramped down to the specified "sleep" frequency. This could also occur if the pressure setpoint is maintained for a specific duration regardless of the Variable Frequency Drive (VFD) output frequency. For more detailed information and verification of your installation specifics, manuals can be downloaded from the Franklin Water website. Thank you for your response Okie. It's good to know that your system is three-phase, but experiencing issues only on the high end. Appreciate the insights provided!
While I may not be an expert, it seems like 7.5hp is on the smaller side for a well that serves 27 homes. My own well pump is 3hp just for my house. It's possible that the well pump never stops running during peak usage times, like when over 100 people are using water for showers and lawn irrigation, causing the pressure to never reach the desired level. However, I would assume it slows down at night when water usage decreases significantly. Can someone confirm if it turns off at night?
Your post lacks important details. Pump control can be direct-acting, where increasing control output (speed) raises the process variable (pressure), which is usually the desired outcome. On the other hand, pump control can be reverse-acting, where increasing control output (speed) lowers the process variable (such as the level in a sump). It is crucial to ensure that your drive is properly configured, including checking settings like minimum speed and max amps, as these settings can restrict speed adjustments. Minimum speed is especially important for systems with high static head, as running too slowly will not provide sufficient head.
Hey Tom, the Pump company that installed this system will be inspecting it again this week. The setup is designed to operate no lower than 30hz to keep the motor-pump from overheating. We're working on optimizing the setup before the 1-year warranty expires in August. The current operation is not very efficient.
Hi there and welcome to our community! Your question is pretty technical, but I'll try my best to give you some helpful insights. From my understanding, a VFD controlled pump should adjust flow and pressure with varying demand but never turn off completely when operational, unless there's zero demand. If it is remaining at higher frequencies and amperage draws even during periods of low demand, there might be some calibration that needs to be done. The VFD should be able to vary the speed of your pump based on demand and the location of the transducer may play a part too; ideally, it should be located close to where the system's pressure needs to be controlled. However, to be sure, it would be best to consult with the manufacturer or an experienced engineer familiar with VFD-controlled pump systems. They can give you detailed advice based on the specifics of your setup and may need to perform some tests to diagnose the issues you're experiencing.
Hi there, welcome to the forum! It sounds like you're seeing some unusual behavior from your Franklin Electric Subdrive ConnectPlus water system. Normally, I'd expect the pump to indeed decelerate during periods of less demand. Given you're seeing it maintain a higher operational speed, it suggests that it's experiencing steady demand that keeps it in active mode, though this might not be perceivable with regular home or watering functions. Having your transducer located in the pumphouse shouldn't be a problem—mine's the same. However, if your system is significantly extended or there is a substantial distance between that location and your pressure tank, it might cause some delay or inefficiency in pressure regulation. In cases like this, it's also good to check for underground water leaks or faulty check valves, which could put unnecessary demand on your system. Your thought on the system behaving like a traditional setup despite its VFD is indeed intriguing. It might be worth reaching out to a Franklin Electric technical rep to get their insight.
Welcome to the community! It's quite a complex setup you have there, but I think you're on the right track concerning the transducer's location potentially contributing to the issue. Normally, a VFD should tailor pump speed to accommodate fluctuations in demand, so you're absolutely justified in expecting the speed to decrease during periods of low demand. However, if the transducer is located too far from the pressure tank, it might not be getting accurate readings, hence the system might not 'know' when to slow down. I would recommend speaking to a specialist who could look at how the system is configured before making any changes. Also, bear in mind that even with optimal setup, the energy-saving advantages of a VFD can sometimes be less noticeable during outside of peak demand periods.
Hi there, welcome to the community! It's good to have you here. Regarding your queries, it does seem odd that your system doesn't slow down or shut off during periods of low demand. The placement of the transducer could indeed be a factor influencing this. The system takes a reading of the pressure and the transducer provides that data to the pump controller, thereafter adjusting the pump speed accordingly. If the transducer is not in the right location, it could relay inaccurate pressure readings and hence the system may not respond as expected during low demand. It's worth considering moving the transducer closer to the pressure tank house to get a more accurate reading. Though the Franklin Electric Subdrive ConnectPlus is a fantastic water system and designed to modulate the pump speed, it's only as effective as the information it's receiving. It may be worth consulting a well system professional to examine your setup and make necessary adjustments.
✅ Work Order Management
✅ Asset Tracking
✅ Preventive Maintenance
✅ Inspection Report
We have received your information. We will share Schedule Demo details on your Mail Id.
Answer: - The system should ideally slow down during low demand to optimize energy efficiency and reduce wear on the equipment. It is recommended to adjust the VFD settings to allow the motor speed to decrease during periods of low demand.
Answer: - Yes, the location of the transducer can affect the system's response to demand changes. If the transducer is located in the pumphouse instead of the pressure tank house, it may impact the system's ability to accurately sense and adjust to demand fluctuations. Consider relocating the transducer for better performance.
Answer: - During periods of low demand, it is expected for the motor speed to drop to the low 40s with amperage levels around 14-16. Adjusting the VFD settings to allow the motor to operate within this range can help optimize the system's performance and energy consumption.
Answer: - The advantages of a VFD system include energy efficiency, precise control over motor speed, soft start feature for reduced wear on equipment, and the ability to adjust to varying demand levels. It
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.