Description
The NPE-A2 is the NPE-S2 with recirculation built in. Navien’s ComfortFlow® system puts a buffer tank, a recirculation pump and the controls inside the unit itself.
What the buffer tank actually fixes
On a plain tankless, turning a tap on and off in quick succession can push a slug of cold water down the hot line — the “cold-water sandwich”. The buffer tank absorbs that, and it also covers the low flow rates that can otherwise fail to trigger the burner.
Definition per Measure Guideline: Transitioning to a Tankless Water Heater, U.S. Department of Energy, September 2012.
The built-in pump recirculates either through a dedicated return line or through your existing supply lines using NaviCirc®, with no external pump or control to add.
Flow rate by temperature rise
How much hot water a tankless delivers depends on how far it has to lift the incoming temperature. Calgary mains run cold, so the 67°F column is the one that matters here.
| Model | 35°F rise | 45°F rise | 67°F rise |
|---|---|---|---|
| NPE-180A2 | 8.4 GPM | 6.5 GPM | 4.3 GPM |
| NPE-240A2 | 11.2 GPM | 8.7 GPM | 5.6 GPM |
Sizing
| Model | Heat input | UEF | Flow at 67°F rise | Typically sized for |
|---|---|---|---|---|
| NPE-150S2 | 18,000 – 120,000 BTU/h | 0.93 | 3.4 GPM | About 2 people |
| NPE-180S2 | up to 150,000 BTU/h | 0.96 | 4.3 GPM | About 3 people |
| NPE-210S2 | up to 180,000 BTU/h | 0.96 | 5.3 GPM | 3 to 5 people |
| NPE-240S2 | 13,300 – 199,900 BTU/h | 0.96 | 5.8 GPM | 4 to 6 people |
How it works
- Dual stainless steel heat exchangers
- Field-convertible gas system (natural gas or propane)
- Low NOx emissions (20 ppm)
- Venting in 2″ or 3″ PVC, CPVC, approved polypropylene or stainless steel — up to 60′ on 2″, up to 150′ on 3″
- Backlit EZNav™ control panel with self-diagnostics, showing temperature, flow rate and cascade status, switchable between °F and °C
- Ready-Link® cascading up to 32 units — at 80% capacity the next unit starts, and the system balances the workload across units
- Common venting up to 12 units, which reduces building penetrations
Warranty
- 15 years on the heat exchanger
- 5 years on parts
- 1 year on labour
What the installation covers
- Removal and disposal of your existing water heater
- Supply and installation of the new tankless system
- All appropriate exhaust, combustion make-up air, gas, electrical and control connections
- System commissioning, start-up and testing to the manufacturer's requirements
- A walk-through so you know how to run it before we leave
- Application, inspection and completion of the municipal gas permit
You are responsible for calling the municipality to arrange the in-home inspector visit; we handle the permit itself.
Before you book
We inspect within reason and assume normal chimney conditions — a straight, clean drop from crown to base so a properly sized liner slides down easily. Offsets, jagged blocks, structural supports, stray screws, damage or misaligned sections can rule out a liner or increase the materials and labour needed. If that happens you are told before any work continues, and you decide how to proceed.
An ENERGY STAR certified tankless water heater uses 30% less energy on average than a storage tank type.
