To install a recirculating pump on a tankless water heater, connect the pump to the hot water line and follow the manufacturer’s wiring and plumbing instructions carefully.
A recirculating pump eliminates the wait for hot water from your tankless system. This guide covers installation steps, pump types, and expert tips to maximize efficiency.
Why Install a Recirculating Pump?
Recirculating pumps solve three common tankless water heater problems:
- Long wait times for hot water at distant fixtures
- Water waste from running cold water down drains
- Inconsistent temperatures in multi-story homes
According to Super Brothers HVAC, these systems can reduce water waste by up to 15,000 gallons annually in typical households.
Types of Recirculating Pumps
1. Traditional Recirculating Pumps
These create a dedicated return line between your farthest fixture and the heater. They work best in new construction where plumbing access is easy.
| Pros | Cons |
|---|---|
| Constant hot water availability | Higher energy use |
| Simple operation | Requires return line installation |
2. Demand-Controlled Pumps
These smart pumps activate only when needed. The Navien NaviLink system offers WiFi control and scheduling through a mobile app.
3. Crossover Valve Systems
These use your cold water line as a temporary return path. They’re ideal for retrofits where adding return lines is impractical.
Step-by-Step Installation Guide
Tools Required
- Pipe cutter
- Adjustable wrench
- Teflon tape
- Voltage tester
- HVAC multimeter
Installation Process
1. Shut Off Utilities
Turn off power to the water heater at the breaker. Close the main water supply valve and drain remaining water from pipes.
2. Mount the Pump
Install the pump on the hot water outlet line, typically within 3 feet of the heater. Ensure arrows on the pump housing point toward your fixtures.
3. Install Crossover Valve
For systems without return lines:
- Identify the farthest fixture from the heater
- Install the thermostatic valve under the sink
- Set activation temperature (typically 95°F)
4. Electrical Connections
Connect pump wiring according to manufacturer instructions. Most residential pumps use 120V power. Consider adding a timer to limit operation during peak hours.
5. System Activation
Slowly reopen water supply valves. Purge air from lines by opening all hot water faucets. Restore power and test system operation.
Maintenance Tips
- Flush the system annually to prevent mineral buildup
- Check crossover valves every 6 months
- Monitor energy usage – sudden spikes indicate pump issues
- Insulate hot water pipes to improve efficiency
Common Installation Mistakes
Avoid these errors for optimal performance:
- Installing pump on cold water inlet (reduces heater efficiency)
- Oversizing the pump (causes unnecessary wear)
- Ignoring local plumbing codes (some areas require special permits)
- Failing to ground electrical connections
For complex installations, consult a professional. The Navien NPE-A2 series requires specific pump models for warranty compliance.
