Navien water heater dhw wait

Looking at the Navien NPE-240A2 Tankless Recirculating Water Heater Installation Manual there are several parameters of interest to me: Recirc Interval Time: Set the recirculation duration. (Default 20 min) Recirc Sample Time: Set the recirculation interval. (Default: 30 Min) Recirc Off Diff. Temp: Set the Recirculation Off offset …

Nov 3, 2023 · I have a less than 2 year old, builder installed Navien water heater that has decided to be in a constant post-purge when it is not being used. The status alternates between POST-PURGE AND DHW-WAIT. I noticed this about a week ago as I heard a vibration upstairs and it was the water heater blower running and now water was flowing or had been ...Optional NPE-S2 recirculation valve. Designed for recirculation of domestic hot water in applications where a dedicated return line is not available. External pump neccessary not included. Part No. PFFW-001, NaviCirc Kit: 30022965A. External recirc pump and check valves not included.View and Download Navien NHB H Series installation and operation manual online. NHB H Series boiler pdf manual download. Also for: Nhb-055h, Nhb-080h, Nhb-110h, Nhb-150h, Nhb-h series. ... DHW control 1. Supply water method 2. Page 109: Setting The Display Options Press the Back button ( ) to return to the previous Item Description screen or ...The Navien tankless water heaters boast low exhaust gas temperatures, which allow the use of PVC, CPVC, System 636, and polypropylene vent systems, saving both time and money. A negative pressure gas valve and a dual venturi system allows for easy field convertibility from NG to LP operation. The Navien systems contain dual stainless steel heat ...Turn off power and water supply. Drain the water heater completely. Prepare a descaling solution in a bucket and put the pump inside it. Connect a submersible pump and hose to the cold water inlet valve. Connect another hose to hot water outlet side and put other end of it in the bucket.A clogged system can also cause your tankless water heater to not heat the water properly. To flush the system, turn off the power supply and the water supply to the heater. After that, open the valves to release any trapped air or debris. Once the system is flushed, turn the water and power back on and check if the water is heating properly.10 Tips on How to Increase Temp on Navien Tankless Water Heater. 1. Locate the Control Panel. Locate the control panel or remote controller for your Navien tankless water heater. The control panel is typically located on the side of the appliance, while the remote controller is often found near a wall outlet. 2.

My house has radiant heat out of an original hot water radiator system from the 30’s. The navien works incredibly well with the original radiator system. The navien gives me both hot water and hot water for my house. I basically had 1000 lbs of 1939 pittsburgh steel taken out of my house and replaced with a box on the wall.Navien 30012033B Dhw Flow Sensor. ... We were experiencing intermittent cold water from our 9 year old Navien NR-240A tankless hot water heater. We even have the recirculation loop to keep hot water in the pipes every 30 minutes. ... In recent months, every time I went to do dishes at the kitchen sink, I would have to wait for an extremely ...How a Combi-boiler Works. Similar to a forced-air heating system, your home’s thermostat senses a drop in temperature and signals the boiler to turn on. Using natural gas or propane, the boiler heats the water in the system. This heated water then flows through your house via radiators, hydronic baseboards or in-floor radiant heating systems ...When a Combi-boiler is used for space heating, the heated water flows from the boiler to radiators, baseboard heaters or in-floor radiant systems that distribute heat throughout the home. Separately, water travels through a domestic hot water heat exchanger delivering endless hot water to the home’s faucets, showers and appliances.Professional Maintenance Tips for Navien Tankless Water Heaters. Scheduling Regular Inspections: Why Professional Check-Ups Are Crucial. Like a well-oiled machine, your Navien tankless water heater needs regular check-ups to keep it running smoothly. Think of it as giving your trusty steed a check-up before a big race.The status alternates between POST-PURGE AND DHW-WAIT. I noticed this about a week ago as I heard a vibration upstairs and it was the water heater blower running and now water was flowing or had been flowing in the house. I cleaned the intake screen and cycled power. The blower stopped but then it started running constantly again.The bottom line is that the Navien Combi-boiler can either be creating hot water on demand for shower/ sinks /Washing machine/ Dish washer (Domestic Hot Water or DHW) or producing hot water for the three heating zones to heat the house - but it can NOT do both at the same time. I belive this is "standard / typical" for any combi-boiler.

To obtain warranty repair service, the end user or homeower must contact the original installer of your Navien product. If the original installer cannot be identified, the end user or homeowner may contact Navien's Technical Administration Department at (800) 519-8794. Proof of purchase is required to obtain warranty service.1. Mineral Build-Up. The most common reason behind your tankless hot water heater making a humming noise is the build-up of minerals. The problem will be even more severe if you live in an area where hard water flows through the pipes. Minerals like Calcium and Magnesium accumulate on the pipes and cause this issue.This innovative accessory will make cascading up to 16 units in 2 banks of 8 easy for emergency same day replacements. The kits are configures in 2, 3, and 4 side-by-side and 2, 4 back- to-back allowing for up to 16 units in 30 configurations. Each kit includes: * 3/4" Service Valves with PRV * 3/4" NPT Ball Valve * 2" Copper End Cap * 2 ...NPE-180A2 premium features and benefits. 2" PVC venting up to 75 feet. Low exhaust gas temperatures allow use of PVC (including schedule 40 PVC), CPVC, polypropylene (rigid and flexible) and stainless steel venting saving time and costs. Vent Installation Detector (VID) for added safety. Dual Venturi for field gas conversions.NHW-199AI premium features and benefits. The patented ComfortFlow® system is the first to include a buffer tank, recirculation pump and fine-tuned controls into a tankless water heater. Allows you to adjust water temperature, operation status and troubleshooting. Monitors vent system for blockage, automatically compensates for range of vent ...

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When the Navien tankless water heater goes into Standby mode, it will show a DHW Wait code on the display. This code refers to Domestic Hot Water supply. It means the unit has an amount of hot water ready to supply but waiting for demand. The duration of time the unit holds the hot water is 5 minutes by default.You should descale your Navien Tankless Water Heater once or twice a year depending on the water hardness. To descale a tankless water heater, you need to run a cleaning solution like vinegar to remove the gunk buildup. Read this article on Navien Tankless Water Heater Maintenance to learn the step-by-step descaling procedure.Says DHW-wait We turned temperature down Left corner has ... our Navien NPE 240S Tankless water heater doesn't seem to be able to keep up with demand since the water ...The navien works incredibly well with the original radiator system. The navien gives me both hot water and hot water for my house. I basically had 1000 lbs of 1939 pittsburgh steel taken out of my house and replaced with a box on the wall. The navien paid for itself in 3 years because it is so efficient.Navien combi boilers can provide whole house heating for small to large homes, and endless hot water for up to 3 showers and a dishwasher at the same time. With heat inputs up to 199,000 BTU/H, our combi boilers are also compatible with a variety of whole house-heating systems including: Finned tube baseboards. Cast iron baseboards.

Find brochures, manuals, guides, labels, specs, drawings, revits & certificates for Navien NCB-240/110H condensing combi-boilers.You should descale your Navien Tankless Water Heater once or twice a year depending on the water hardness. To descale a tankless water heater, you need to run a cleaning solution like vinegar to remove the gunk buildup. Read this article on Navien Tankless Water Heater Maintenance to learn the step-by-step descaling procedure.Hi there my tankless water heater model NPE-21042(ng) is not making Hot water. I tried restarting it several times then it goes into standby mode, I turn the water on and it show the GPM usage, the. IFind brochures, manuals, guides, labels, specs, drawings, revits & certificates for Navien NHB-110 condensing heating boilers. Where to buy. Residential. Residential Products. Efficient and earth-friendly products designed for any size home. ... High-efficiency condensing and non-condensing tankless water heaters offer endless hot water and ...Designed for retrofit and new construction, the Navien H2Air Kit™ includes an add-on controller to integrate space heating and DHW between any NPE-A series tankless water heater and a hydronic air handler. Optional Remote Control. Hot water temperature control. Function to set the number of initial activating water heaters for cascade system.Navien's sleek wall-hung combi-boilers occupy 80% less space than traditional floor standing boilers and tank water heaters. Expanded DHW capability For increased domestic hot water flow demand, the NCB-H can be cascaded with up to 15 NPE-2 units. Easy access to DHW module and valves All components of DHW module including water feed valve, flowFeb 13, 2022. #1. Hello all, I recently moved into a brand new 2 story house that has a Navien 240A2 in it. In the morning it usually takes 4 or more minutes for water to become hot in one of the locations that may be furthest from the water heater (not 100% if it is the furthest). I have read quite a few posts on here, as well as the manual ...The Navien NCB 240 Tankless Water Heater solves all those concerns. Technical Specifications. Dimensions - 17 inches (43.2 cm) x 12 inches (30.5 cm) x 28 inches (71.2 cm) ... However, there are a couple of products that come into view that are similar to the Navien NCB domestic hot water system.Water Heater; CH-240; NAVIEN CH-240 Manuals. Manuals and User Guides for NAVIEN CH-240. We have 6 NAVIEN CH-240 manuals available for free PDF download: Service Manual, ... Domestic Hot Water Outlet Collar. 140. 9 Components Diagram and Part List. 141. Case Disassemble. 141. Burner Disassemble. 143.No Water Flow. Dirty/clogged cold water intake filter, solenoid valve issue. Clean the filter/hire a professional. Flow Sensor Problem. Fan not spinning, damaged fan blades, damaged or faulty sensor, etc. Replace the flow sensor/hire a professional. Heater Constantly Running. Traditional storage unit operation.Do you know how to test a thermocouple on a gas valve? Find out how to test a thermocouple on a gas valve in this article from HowStuffWorks. Advertisement Inside your gas-operated...

Discover the essential steps to reset your Navien tankless water heater in this comprehensive video tutorial presented by David Clark from Hvaclaboratory.com...

Part Number: (30003873B) Wall flange designed to work on 3" intake and exhaust pipe for a clean installation look in location where the pipe goes through the wall. Find Navien accessories and parts kits for venting & termination, plumbing, Wi-Fi control & field service for tankless water heaters, boilers & combi-boilers.“DHW Wait” on a Navien water heater refers to when the unit delays the delivery of Domestic Hot Water (DHW). This delay is intentional and is usually associated with certain operational aspects of the water heater. 2. How to reset a Navien tankless water heater? Resetting a Navien tankless water heater can vary slightly depending on the ...Press the Power button on the front panel to turn off the water heater. Disconnect the power supply to the water heater. Remove the front cover of the water heater. Remove the screw that secures the air intake filter and then remove the filter. The filter is located at the top left of the water heater.Convenience: Tankless water heaters provide a more consistent flow of hot water than traditional tank water heaters. This means you don't have to wait for water to heat up from the tank. Durability: Navien tankless water heaters are built to last. They come with a 10-year warranty on the heat exchanger.Step 1: Turn Off The Unit’s Power Source. Any kind of work you do related to a water heater comes with various risks since they run on electric power. That is why it is necessary to turn off all power supply to the unit. First, turn off the Navien tankless water heater by pressing the power button. Then turn off the breaker by unplugging it.Navien 30012033B Domestic Hot Water Flow Sensor For NCB-180, 210, 240 Condensing Gas Combination Boiler NAV30012033B. Additional information. Weight: 0.3 kg: Dimensions: ... Need Service call for your Water Heater, Air Conditioners and Furnace? We also do Tune ups and Maintenance. Call us at 1.647.558.4079 anytime or email at ...So our new hot water heater (Navien NPE-240A2) has a dedicated recirc line and pump to make sure you have hot water instantly on the other side of the house, but the built-in logic is incredibly inefficient, which runs …When a Combi-boiler is used for space heating, the heated water flows from the boiler to radiators, baseboard heaters or in-floor radiant systems that distribute heat throughout the home. Separately, water travels through a domestic hot water heat exchanger delivering endless hot water to the home’s faucets, showers and appliances.See full list on lildutchuncle.com

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Ontario, Canada. Jun 12, 2020. #2. First off, the installation must be plumbed slightly differently for recirculation to work in a cascaded system. Page 34 of the NCB-E Installation Manual, shows a check valve is to be installed in the incoming cold feed line to the NPE device, and a 120 VAC normally closed solenoid valve is to be installed in ...Navien's NPE-210S2 condensing tankless water heater for commercial & residential applications uses high-efficiency technology to provide endless hot water. ... DHW Capacity. Model: NPE-210S2: Natural gas: 12,000 - 180,000 BTU/h (3.516 - 52.74 kWh) ... Details about our residential warranty for Navien's NPE series tankless water heater, ...Domestic hot water: 10,700 - 199,900 BTU/h (3.135 - 58.571 kWh) Efficiency ratings: Efficiency rating for NG & LP (UEF) 0.81: Flow rate (DHW) ... Details about our commercial warranty for Navien's NPE series tankless water heater and NHB series condensing boiler can be found here.Condensation inside Navien tankless water heater. September 2021 edited September 2021. My parents had Navien tankless water heater installed at their home about seven years ago. Every time I am in town (if I remember) I will try and do some basic maintenance on the unit, including open it up clean the filter and interior of the cabinet.I believe the static pressure on the heating side of Navien combi boilers needs to be at least 12 psi for it to fire up at all. When you pull the radiator either cap off valve isolate the missing radiator section and check that the pressurize the heating system side is still running 12 psi (30 max, but 15 psi is enough for most residential ...Find brochures, manuals, guides, labels, specs, drawings, revits & certificates for Navien tankless water heaters. Where to buy. Residential. Residential Products. Efficient and earth-friendly products designed for any size home. Overview. Tankless Water Heaters. High-efficiency condensing and non-condensing tankless water heaters offer endless …Optional NPE-S2 recirculation valve. Designed for recirculation of domestic hot water in applications where a dedicated return line is not available. External pump neccessary not included. Part No. PFFW-001, NaviCirc Kit: 30022965A. External recirc pump and check valves not included.Power the unit back up and wait for 30 minute to see if the unit starts heating again. Control Board Is Malfunctioning. If you notice your Navien’s control board is malfunctioning (for example, it’s not displaying at all, the device is not properly functioning, etc.) then it is likely the control board that needs to be replaced.When I turned it back on it had the "DHW-Wait" and after a few minutes it went to "Stand-by". ... My Navien 240a2 tankless hot water heater is stuck in standby mode. I have unplugged it for 20 minutes, plugged it back in. I have done the Navien reset as well. we have gas, we have water. ...April 26, 2023 by David. Navien tankless water heater standby mode means that your heater has power and it’s operational but it’s not currently heating any water. The heater goes into this mode when there’s no demand for hot water to save energy. The newer generation of Navien heaters has made it really easy to know when you’re in standby …If you are not familiar with how the Navien tankless water heater works, or the advantages of the Navien tankless water heater, then this video is for you. ….

Product Downloads > NPN Installation and Operation Manual. Download file. Email file. Copy link. Home. Close. Navien's water heaters, boilers, hydro-furnaces & water treatment solutions provide innovative high-efficiency technology for residential & commercial projects.Navien NPE-2 Series, New NHW-A Series, & NPN Series high-efficiency tankless water heaters provide endless domestic hot water, all while keeping your utility bills low. A tankless water heater is a type of water heater that doesn't use a storage tank to heat water. Instead, hot water is produced only when you need it.Our new NHB-H boiler series is the next in a long line of innovations from Navien. All boilers have Navien's advanced burner system, an industry-leading AFUE of 95% and turndown ratios up to 15:1. Now available in four sizes: NHB-55H, NHB-80H, NHB-110H and NHB-150H.Northern PlumbingCombination heating and DHW system using NPE-A2 Series condensing tankless water heaters An add-on accessory for the Navien NPE-A2 Series tankless water heater that creates a high efficiency space heating and endless domestic hot water system. Additional features of the H2Air System. Domestic hot water priority or simultaneous domestic hot …HYDRO-FURNACE. Navien Resale Policy - Consumer purchases through the internet or other e-commerce channels shall void Navien's warranty. >> Warranty Terms . Navien's water heaters, boilers, hydro-furnaces & water treatment solutions provide innovative high-efficiency technology for residential & commercial projects.Product Downloads > NPE User's Information Manual. Download file. Email file. Copy link. Home. Close. Navien's water heaters, boilers, hydro-furnaces & water treatment solutions provide innovative high-efficiency technology for residential & commercial projects.Find brochures, manuals, guides, labels, specs, drawings, revits & certificates for Navien NPE‑A Series condensing tankless water heaters. Where to buy. Residential. Residential Products. Efficient and earth-friendly products designed for any size home. Overview. Tankless Water Heaters. High-efficiency condensing and non-condensing tankless …How to replace a leaking heat exchanger on a Navien NPE series tankless water heater. Although Navien NPE series is my favorite tankless water heater due to ... Navien water heater dhw wait, “DHW Wait” on a Navien water heater refers to when the unit delays the delivery of Domestic Hot Water (DHW). This delay is intentional and is usually associated with certain operational aspects of the water heater. 2. How to reset a Navien tankless water heater? Resetting a Navien tankless water heater can vary slightly depending on the ..., Certifications. English. NPE-150S2 AHRI Certificate. NPE-180S2 AHRI Certificate. NPE-210S2 AHRI Certificate. NPE-240S2 AHRI Certificate. Find brochures, manuals, guides, labels, specs, drawings, revits & certificates for …, NPE-150S. The NPE-150S is the smallest water heater available from Navien. Still, it offers 6.8 GPM, which is more than enough for a small home and sufficient for most average-size homes. Plus, as it is cascading capable, it can be appropriate for even large homes and commercial applications., Product Downloads > NCB-H Installation and Operation Manual. Download file. Email file. Copy link. Home. Close. Navien's water heaters, boilers, hydro-furnaces & water treatment solutions provide innovative high-efficiency technology for residential & commercial projects., Jan 10, 2024 · Struggling with your Navien tankless water heater? Watch our easy-to-follow guide on how to reset your unit and troubleshoot common issues. Don't forget to s..., Is your Navien tankless water heater shutting off unexpectedly? Watch our step-by-step guide to troubleshoot and fix the issue, ensuring a continuous hot wat..., When a Combi-boiler is used for space heating, the heated water flows from the boiler to radiators, baseboard heaters or in-floor radiant systems that distribute heat throughout the home. Separately, water travels through a domestic hot water heat exchanger delivering endless hot water to the home's faucets, showers and appliances., April 26, 2023 by David. Navien tankless water heater standby mode means that your heater has power and it’s operational but it’s not currently heating any water. The heater goes into this mode when there’s no demand for hot water to save energy. The newer generation of Navien heaters has made it really easy to know when you’re in ..., Most Common Navien Tankless Water Heater Error Codes and How to Fix ThemDownload the Free Navien Tankless Water Heater Guidehttps://www.monkeywrenchplumbers...., NPE-210A2 premium features and benefits. 2" PVC venting up to 75 feet. Low exhaust gas temperatures allow use of PVC (including schedule 40 PVC), CPVC, polypropylene (rigid and flexible) and stainless steel venting saving time and costs. Vent Installation Detector (VID) for added safety. Dual Venturi for field gas conversions., 2. Water Heater Goes Cold. Examine the heat exchanger: Remove any debris or blockages that may be affecting the heat exchanger's performance. Verify the gas supply: Confirm that the gas pressure is within the acceptable range and there are no obstructions in the gas line. 3. No Water Flow., The Pump Excercise feature is intended to periodically activate the pump to ensure the water will be circulated and to also ensure the pump seals will not dry out. The default Excercise setting will activate the pump for 30-seconds every 24-hours, but the activation time is adjustable to between 1-240 seconds, and the interval is ajustable to ..., Navien Tankless water heater not supplying hot water... the message on the display says Post Purge then cycles to Start-up ... Once water turns off it shows msg of post purge and then DHW-wait … read more. Master Plumber. Retired Owner Of Plumbing Repair Company. State License Master Repair Plumber. 830 satisfied customers. Power went …, At the push of a button, Navien's HotButton accessory activates the internal recirculation pump and gas-fired burner to heat up the water in the supply lines. This gives users hot water when they need it, saving water and money. It is now available as an add-on accessory for all NPE-A models (NPE-180A, NPE-210A, NPE-240A). It is compliant with California Title 24., Navien was first to offer dual stainless steel heat exchangers, rather than copper, which extends the life of the unit by resisting corrosion. Energy Star highest rated gas water heater The NPE is the most energy efficient* tankless water heater in the industry. Our condensing technology delivers performance up to 0.97UEF/0.99EF., Struggling with your Navien tankless water heater? Watch our step-by-step guide to understand error codes, perform easy fixes, and maintain your unit for opt..., high efficiency Condensing Combi-Boiler. Smart controls LCD display, quick dial wheel & Setup Wizard. Advanced stainless steel dual heat exchangers. 15:1 DHW and up to 10:1 heating TDR. Field convertible gas system (NG/LP) up to 10,100 ft. Capable of cascading up to 15 NPE water heaters. Capable of common venting up to 7 NPE water heaters., The NPE series offers the ultra high efficiency condensing technology that makes Navien stand out from the pack. These models have near perfect EF ratings of 0.99 (for the Standard) and 0.97 (for the Advanced). Meaning these units convert almost all of their energy to heat. Compare this to 0.81 for your average tankless water heater., Get genuine Navien factory OEM repair parts for your CH-180-NG tankless water heater. All Navien parts are brand new in the original factory packaging and are guaranteed to fit and function properly. This is the NG model which means that it uses Natural Gas. We have fast FREE SHIPPING on all orders over $99 and ship all orders within 1 business ..., Best solution is to rise the difference between primary water and DHW. Usually is not only the water flow to trigger the boiler, but a low temp on primary water. On most boilers primary water is kept 20°C above DHW. My 15 years old Hermann can handle as low as 2,5L/min, so I think you have a setting problem on the boiler' computer., Hello all, I have a new Navien Tankless water heater installed in the walk in closet las year on 1st floor. ... 1.9K Domestic Hot Water; 5.2K Gas Heating; 92 Geothermal; 160 Indoor-Air Quality; 3.2K Oil Heating; 59 Pipe Deterioration; 851 Plumbing; 5.8K Radiant Heating; 375 Solar; 14.5K Strictly Steam ;, Navien npe 249a2 installed in January 2023 and working fine until three weeks ago. Upon request for hot water, flow rate only reads 0.5 gpm even though..., Domestic hot water: 10,700 - 199,900 BTU/h (3.135 - 58.571 kWh) Efficiency ratings: Efficiency rating for NG & LP (UEF) 0.81: Flow rate (DHW) ... Details about our commercial warranty for Navien's NPE series tankless water heater and NHB series condensing boiler can be found here., Feb 23, 2014 · Ive seen what you describe. In domestic water heating mode, the closed side heating pressure increases, kicks off the relief valve and unit shuts off. after about two minutes it refills and restarts. Could be other issues but this happens a lot on the install of this unit by contractors that don't understand boilers., The temp of the supply was definitely 140, right until it hit the T in the Navien manifold, at which time the hot water blended with the circulating water and was cooled. Return temp was very cool, maybe 100 deg F. In the morning the house temp was 5 degrees below thermostat setting (63 deg F, set at 68 deg F)., Is your Navien tankless water heater not producing hot water as expected? Watch our step-by-step guide to troubleshoot and fix common issues yourself. Learn ..., Error codes are common for tankless water heaters, but some are more common than others. Check out the most frequent codes and how to fix them., If the water gets hot then it's the check valve. Usually only takes a few minutes to replace and is cover under naviens warranty. 4. GreenEngrams. • 1 day ago. I would call Navien, they may be able to help you troubleshoot. It could be a bunch of stuff, if your unit is hooked up to a recirculation line or comfort tee, your manufacturer ..., I've got a Navien Combi 240a which is giving inconsistent and low domestic hot water out. I do not have the remote but the LED on the unit shows supply temps which oscillate from 180 down to 150. I assume this is not the DHW output because the DHW output pipe is only warm to the touch. The mixing loop for the hydronic heat, however, is scalding., The new Navien NPE-A2 series are the most innovative condensing tankless water heaters on the market today. These tankless water heaters deliver a continuous flow of hot water for as long as you need it. There's no waiting for a storage tank to warm up. A few of the new features are listed below. A - 2″ PVC up to 75 feet and 1/2″ gas up ..., David Stewart. Hours:(Daily) 7AM-9PM. Telephone:(208) 758-5570. Email: [email protected]. Navien - Water Heater Age Lookup. Compare your serial number to determine the age of your unit. If you would like to suggest an edit or update to this site, please email comments to [email protected]. DISCLAIMER., Navien water heater with the recirculating pump not working. Ensure the recirculation pump was installed correctly. And the heater has been set to recirculation mode. Refer to the user manual to locate the Hot Button and then press it to activate hot water recirculation. If you are unsure of whether the recirculation pump was correctly …, The Navien NPE-180A2 tankless water heater has a max flow of 4.3 gallons per minute (GPM). This Navien tankless water heater produces the lowest GPM in the NPE-A2 series, but that doesn’t mean it’s inferior in any way. At 4.3 GPM, the NPE-180A2 tankless water heater can simultaneously provide hot water to one or two fixtures.