Grundfos CU301 &
CU302 Installation
Constant Pressure. Variable Speed. Smarter Well Control.
The Grundfos CU301 and CU302 are the gold standard in residential constant pressure well control. We install, program, and service both controllers throughout Calvert and Anne Arundel County — with same-day service available for well emergencies.
What Is the Grundfos CU301/CU302?
The Grundfos CU301 and CU302 are variable frequency drive (VFD) controllers for submersible well pumps. Instead of running your pump at full speed and cycling it on and off to maintain pressure, these controllers run the pump continuously at variable speed — using only the energy needed to maintain your set pressure point.
The result is constant pressure within ±2 PSI regardless of demand. Whether one faucet is running or five fixtures are open simultaneously, pressure stays steady. No surges when the pump kicks on. No drops when demand spikes.
The CU301 is the standard constant pressure controller — reliable, proven, and ideal for most residential wells. The CU302 adds dry-run protection, overload protection, data logging, and Bluetooth connectivity for wells with low-yield risk or homeowners who want remote monitoring capability.
±2 PSI
Pressure Accuracy
30–50%
Energy Savings
5–10 years
Pump Life Extension
Why Upgrade to Grundfos Constant Pressure?
Constant Pressure
±2 PSI regardless of demand — no pressure surges when the pump kicks on, no drops when multiple fixtures run simultaneously.
Energy Savings
Variable speed operation uses only the energy needed for current demand — typically 30–50% less energy than traditional on/off pump cycling.
Extended Pump Life
No start/stop cycling stress. The pump runs smoothly at variable speed, eliminating the electrical and mechanical stress of repeated hard starts.
Dry-Run Protection
The CU302 detects low water conditions and shuts down before damage occurs. Automatic restart once the well recovers.
Soft Start
Gradual ramp-up eliminates electrical stress on motor windings — the leading cause of motor insulation failure in submersible pumps.
Remote Monitoring
The CU302 logs operating data and connects via Bluetooth to the Grundfos GO app — fault history, runtime, and pressure data at your fingertips.
CU301 vs. CU302 — Which Is Right for Your Home?
Both deliver constant pressure. The CU302 adds protection and monitoring for wells that need it.
Grundfos CU301
Standard Constant Pressure
- Constant pressure control for single-phase submersible pumps up to 3 HP
- Maintains steady 40–60 PSI regardless of demand fluctuations
- Soft-start technology reduces pump wear and extends motor life
- Built-in dry-run protection shuts pump off if well runs low
- Automatic restart after dry-run event once water recovers
- Compact design installs in standard electrical panel or junction box
- Compatible with most Grundfos and third-party submersible pumps
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Best for: Reliable high-yield wells
Grundfos CU302
Advanced with Protection & Monitoring
- All CU301 features plus advanced diagnostics and monitoring
- Bluetooth connectivity for remote monitoring via Grundfos GO app
- Detailed fault history and performance logging
- Adjustable pressure setpoint from 20–80 PSI
- Enhanced motor protection with thermal overload detection
- Ideal for homes with variable demand or irrigation systems
- Three-phase pump compatibility (select models)
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Best for: Low-yield wells or variable demand
Our recommendation: Choose the CU302 for wells with low-yield risk, seasonal water table fluctuations, or if you want remote monitoring. Choose the CU301 for reliable high-yield wells where the primary goal is constant pressure and energy savings.
Installation Requirements
What we verify before and during every Grundfos controller installation.
What's Included in Every Installation
We provide a written estimate before any work begins. Every installation includes parts, labor, programming, and testing.
CU301 installation
Controller, wiring, programming, and testing
CU302 installation
Includes advanced protection configuration
With new Grundfos pump
Complete constant pressure system
Annual service visit
Inspection, testing, and firmware updates
Our Installation Process
System Assessment
We verify pump compatibility, check electrical panel capacity, measure existing pressure, and confirm the correct controller model for your well.
Electrical Preparation
We pull any required permits, prepare the wiring, and install the controller in the appropriate location — typically near the pressure tank.
Installation & Programming
Controller installed, wired, and programmed to your desired pressure setpoint. CU302 Bluetooth configured and tested with the Grundfos GO app.
Testing & Documentation
Full system test under load — multiple fixtures running simultaneously. We verify pressure stability and provide documentation for your records.
Frequently Asked Questions
What is the difference between the CU301 and CU302?
The CU302 adds dry-run protection, overload protection, data logging, and Bluetooth connectivity. For wells with low-yield risk or variable demand, the CU302 is the right choice. For reliable high-yield wells, the CU301 provides excellent constant pressure with a simpler feature set.
Can the Grundfos CU301/CU302 work with my existing pump?
It works best with Grundfos SQ and SQE pump series. It is also compatible with many Franklin Electric and other submersible pumps. We verify compatibility before installation. If you have a different pump brand, a Cycle Stop Valve may be a better option.
How does constant pressure feel different from a standard system?
With a standard system, pressure drops when multiple fixtures run and surges when the pump kicks on. With constant pressure, pressure stays steady at all times — most homeowners notice the difference immediately, especially in the shower.
Does a constant pressure system eliminate the pressure tank?
No, a small pressure tank (2–4 gallons) is still required to protect the pump from rapid cycling. But it can be much smaller than the 20–80 gallon tanks used in traditional systems.
How much energy does a Grundfos constant pressure system save?
Variable speed operation typically reduces pump energy consumption by 30–50% compared to a fixed-speed pump cycling on and off. The savings depend on your usage patterns and current pump efficiency.
What happens if the CU301/CU302 controller fails?
The pump won't run. We stock common replacement parts and can usually restore service quickly. The controllers are reliable — most last 10+ years with no issues.
How long does installation take?
Most installations take 3–5 hours including electrical work, programming, and testing. We schedule a half-day appointment for most Grundfos controller installations.
Is a permit required for Grundfos installation?
Electrical work requires a permit in most Maryland jurisdictions. We handle all permits and inspections — you do not need to do anything.
Can the CU302 detect when my well is running low?
Yes — the CU302 monitors pump performance and detects the electrical signature of a pump running in low water. It shuts down before damage occurs and attempts automatic restart after a configurable delay.
What warranty comes with the Grundfos CU301/CU302?
Grundfos provides a 2-year manufacturer warranty on the controller. We provide a 1-year labor warranty on installation. Extended warranties available.
Grundfos CU301/CU302 Service Areas
Serving Calvert County and Anne Arundel County, Maryland.
What Our Well System Customers Say
Real reviews from real Southern Maryland homeowners.
Jess
Local Guide
Southern Maryland
May 2026
"We had a mystery leak in our bathroom and everyone who saw it was convinced it was coming from inside the wall. He came out, checked everything, and was super thorough instead of just guessing. Turns out it was actually a leak from the toilet tank that was dripping in a way that made it look like it was coming from the opposite wall. He was super patient with all of our questions and explained the fix. We really appreciated his professionalism and transparency. Having an older home, it can be stressful not knowing what kind of repair you're walking into. I highly recommend him if you want someone trustworthy and knowledgeable who genuinely just wants to help."
Joshua Scheper
Local Guide
Southern Maryland
May 2026
"I've worked with Deep Dive Plumbing Maryland several times and always come away amazed at how thorough they are. I would definitely recommend them."
Diane Holloway
Chesapeake Beach, MD
July 2026
"We had orange staining on everything — sinks, toilets, the shower. Deep Dive came out, tested our water, and installed an iron filter and acid neutralizer. The difference was immediate. No more staining, no more metallic taste. They took the time to explain our water chemistry in plain language and sized the system correctly for our household. Couldn't be more satisfied."
18-Month Labor Warranty
Every job we complete — including Grundfos constant pressure system installation — is backed by our 18-month parts and labor warranty. If something we installed or repaired fails within 18 months, we come back and make it right. No arguments, no service call fees.
- 18 months on all labor
- Manufacturer warranty on all parts
- No service call fee for warranty work
- Same technician returns when possible
Financing Available
Well systems, water treatment, and major plumbing repairs are significant projects. We offer financing options so you can get the work done right without waiting.
- Flexible payment plans available
- Apply in minutes — quick approval
- No prepayment penalties
- Ask us about current financing offers
Ready to get started?
Call us or request an estimate online. Written estimate before any work begins.
Related Well Water Services
Ready for Constant Pressure?
We install Grundfos CU301 and CU302 controllers throughout Calvert and Anne Arundel County. Same-day service available for well emergencies.