The cost of flushing a water heater depends on the area and the quality of the plumber. Share it with us! This instructable will show you have to perform a tankless water heater flush on a Navien brand device, but it can be applied to any tankless water heater as long as you can locate the corresponding components on your machine. The minimum static gas pressure of a tankless water heater is 4.0 W.C. for natural gas and 8.0 W.C. for propane. Next open the lever that controls the cold water inflow and allow about 4-5 gallons of water to flow through the tankless water heater and out the hot water hose into the bucket. It is used to regulate the water flow of the system to a minimum rate. Rheem fault code 29 - This code indicates that the heat exchanger outlet temperature is too low. Attach the front cover and restore the power to the unit. Corroded heat exchanger fins> Descale the scale deposits by flushing the water heater. This is such useful information! Inspect the plumbing pipe and look for corrosion buildup in the water lines. You can use a vacuum to remove dust. But the factor needs to be considered based on the tankless unit size and the hot water demand for your household. To remove the air filter once you've unscrewed the one screw, first pull slightly towards you and then slide the whole thing to the left and angle it slightly so it will slide over the motor. Here might be one more reason to add ducts to a HPWH: The plumber installers put the HPWH with the output fan directly facing the basement wall 7.5" away. of faulty combustion, which may have been brought on by a broken flame rod or fan motor, or by a restriction in the air intake. On the contrary, too high flow causesoverheating. I bought a generic brand from Safeway and the total was $16 for 4 gallons. Next located the single screw holding the air intake filter in place. All the tankless water heaters use a few vent pipes to continue the combustion process. 316 Stainless Steel; Watermark certified; High static pressure (3MPa) Low pressure loss @ design flow rate (2 to 10kPa) August 2, 2022. There is no on or off switch so it'll turn on as soon as you plug it into the wall socket. Water passes through a secondary heat exchanger first which preheats the water before it flows through the primary heat exchanger. That's it. Blocked or obstructed venting or exhaust flue. In connection with your providing me with your personal information, we must advise you that information about Rheems practices regarding your personal information is located in Rheem's Privacy Notice located here. Check for any clogs or damages and service them. More about us. To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. Pump control knob allows adjustment of the differential between the inlet water temperature and outlet air temperature. 3. Take the filter screen under running and wash off all the filths and grim stuck on it. Earn double your bonus miles when booking flights online with Vietnam Airlines to enjoy SkyPriority benefits. The condensate trap is located at the bottom of the unit. What happens if I dont flush your tankless water heater? For this instance, you can do as follows:Flush the water heaterOnce or twice a year.Clean the combustion componentsOnce a yearClean the air filter & water inlet filterEvery 3 to 4 weeksInspect the exhaust or ventingOnce a year. 1100 Abernathy Road, Suite 1700 Atlanta, GA 30328, Rheem Manufacturing ranks as the global leader in the manufacture of high-quality, sustainable, and innovative water heaters, tankless water heaters, air conditioners, furnaces, pool heaters, and HVAC systems for residential and commercial applications, and is a full member of AHRI, the, Inflation Reduction Act and Tax Credits Find out more, Air-Conditioning, Heating, & Refrigeration Institute, Industry first! When this code appears on the controlled display, your heater may shut down as a safety precaution. Wondering how to clean it? Question You would probably need a boiler with a heat exchanger to make this work. Check the heat exchanger, the blower motor , the exhaust flue , and the inlet flue for blockages . So, it is essential toset the temperature within a specific range. The air return path is pretty short, so there's not much mixing of air before some of that output air returns directly to the HPWH air intake. *Based on a comparison of Rheem tankless models having the Hot Start Programming against consumer reviews of leading competitor models. Let me know if you have questions of I need to clairify anything. During the ignition process, the rods clog with the shoot that interrupts in sensing of the flame. Instructions for Residential Geothermal Maintenance, set and maintain the proper temperature of your tankless water heater system, Noritz Tankless Water Heater Code 16 [Why + How To Fix], Noritz Tankless Water Heater No Water Flow [Reasons + Fixes], Noritz Tankless Hot Water Heater Codes 11 And 12 [Why + How To Fix], Bradford White Water Heater No Status Light [Why+ How To Fix], Noritz Tankless Water Heater Code 14 [Reasons+Solutions], Clean the air filter & water inlet filter. Its better to clean the water heaters exterior surface at least once or twice a week. Subscribe to the blog so you receive blog posts that are relevant to you. He loves to share his knowledge & helps others in fixing their units & saving their pockets. Check for adequate combustion air ventilation openings and clean if necessary. US with dual stainless steel condensing heat exchanger Performance. on Introduction, Can the pump and exhaust hoses be attached directly to the hot/cold filter nipples if I dont have service caps? The water then flows into the secondary heat exchanger, followed by the primary. Generally, you will find the 100F default setting on the remote control display. Follow the below few phases to clean your heaters combustion system: First off, disconnect the cover panel from your tankless water heater front. You need to clean it as well. In such cases, a blockedneutralizercreates an interruption in the continuous flow of water and the water temperature never reaches the set temperature. Blocked or obstructed venting or exhaust flue.> Inspect all the intake and exhaust vents of your tankless system for any blockages.> Clean the vents. Disconnected the vent structure from the water heater.> Ensure the flapper valve at the top of the heat exchanger moves freely with the vent termination of the water heater. When done, reassemble it back in place and ensure a snug connection. If you would like to change your settings or withdraw consent at any time, the link to do so is in our privacy policy accessible from our home page.. This process pulls heat from the exhaust causing a vapor to form which then cools the exhaust to a much lower temperature allowing for lower cost materials such as PVC to be used for venting. Thats all from us here. 10. We and our partners use cookies to Store and/or access information on a device. You'll hear water rushing into your system. It has a max BTU output of 110,000 and a max 6.6-GPM. All Navien units (water heaters, combi-boilers and boilers) have inlet air screens inside the cabinet just below the air intake collar to prevent debris from being pulled into the blower, burner and heat exchanger assembly. If maintenance is up to date: Check the water inside the neutralizer: Measure the electrode's water level. All models are compatible with 1/2" gas line. Warranty: 12-year limited warranty on heat exchanger, 5-year limited warranty on parts and 1-year in-home labor warranty Reliable hot water solution from Rheem, the global leader in water heating Need more water for larger homes, look to our high GPM models or use the Quick Connect Cables (sold separately) to connect 2 or more tankless units to . First off, take off the cover plate from the front place of your tankless water heater. Before that, dont forget to turn off the gas supply. Higher chances are the venting and exhaust flue are blocked with shoots. Step 2.5 : after removing power from the unit, turning off the gas, and the cold water supply, but before you shut down the hot water supply valve, open a few hot water taps in the home, and let the water drain that way.It's less messy and less chance you could burn yourself.Once the water flow has tapered off from the tap, head back to the unit, and close off the hot water supply valve.also be aware, some systems will have an additional valve plumbed into the service ports, which makes it easier to open them without water coming out all over your hand.Otherwise, great write up! Follow us on social media to stay up to date on all of our useful blog content. To fix it, you need to check the front panel and the air filter door. You will find a plastic knob figured water inter filter just next to the gas inlet valve at the bottom of your tankless water heater. So, it is recommendedflush a water heater at least once a year at the minimum to keep it running smoothly. So, you need to ensure the snugly fitted exhaust connection with the vent termination on the top of the heater. Rheem makes a special outlet duct, but is out of stock. To schedule water heater services in Rockville, MD with trained and licensed plumbers familiar with working with water heaters, look to us! So as for the solutions, you need to descale and flush your water heater to remove the scale build-up from the heat exchanger. Tip #2: There should be a minimum of 12 inches of vertical and 12 inches of horizontal difference between the intake and exhaust venting. Rheem Prestige RTGH is a series of high efficiency condensing tankless gas water heaters designed for continuous hot water . I would first start with the cold water valve. Plus, ensure a snug wiring connection of the blower Molex connectors with the PCB. An example of data being processed may be a unique identifier stored in a cookie. The factors depend on how well you are maintaining your water heater. Recirculation Inlet Filter Disconnect the power supply to the water heater. Manual provided with your tankless water heater for detailed instructions. It indicates the malfunctioning in the air intake filter switch. Don't worry it's not hard to get to at all, but you have to first remove the tankless water heater face plate. Remove the vent hood if you can. Gas Valve System Air ratio valve Minimum Flow Activation Flow 0.5 GPM Minimum Continuous Flow Rate 0.4 GPM Internal Pipe Material STS 304, Copper Tubing Water Holding Capacity Under 2 Gallon Water Pressure MAX Hot water 150 psi MIN 15 psi Gas Pressure Nat. Overheat Film Wrap Safetly shuts down the heater at unsafe temperatures. . The highlighting feature of Takagi T-H3-DV-N tankless water heater filter system is that it operates on natural gas and is extremely energy efficient and provides an on-demand hot water supply without ever running out. Air Intake The recirculation pump operates on either timer settings, custom schedule or . . The outlet vent is 11.5 inches from top screw to bottom screw. Piping in the heat exchanger goes back and forth where the water is heated continuously before exiting. Water Residential Gas Rheem Exclusive! The article about tankless water heater parts explains the main components of the electric and gas water heating appliances that heat water on demand. Low profile 34-inch design is lighter, easier to handle and leaves room for optional accessories. Do let us know if you face any trouble while doing so. Question Cryptex - 10 Steps for 110 Possibles Designs, 3D Printed Futuristic Space Age Wall Clock. If you dont flush your tankless system, mineral deposits build up in greater amounts which prevents the unit from normal heating activity. How to Fix it. Call for service. 3.5 3.5 out of 5 stars (7) $709.00 $ 709. 2. Step #1: First, take off the front cover from your tankless water heater system. if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'fireplacehubs_com-mobile-leaderboard-1','ezslot_20',116,'0','0'])};__ez_fad_position('div-gpt-ad-fireplacehubs_com-mobile-leaderboard-1-0');Vacuum up the entire area as much as you can. It's important to perform a flush with food-grade, white vinegar at least once every 12 to 18 months. As with other above maintenance attempts, it is quite essential to inspect the exhaust or venting of your tankless system. 2. 2 on top and 2 on bottom. Then The PCB (control board) shows the error code. It will be attached to the three fan screws. Question Facebook @RheemWater Tip #2: If it is gas operated water heater, the next step would be to turn off the gas shut-off valve. If you want to descale your water heater, you will need an effective flush kit that generally costsbetween $100 and $200. 1. Clean out the clogged cartridge of the faucets. Make sure they are not wet. Here, you can also watch the video given below on how to fix the Rheem tankless water heater ER 99. The months of March and April are the sunniest and hottest in the year, peaking at an average high temperature of 94 F (34 C) in the latter month. You need to go through a regular inspection of these two essential elements and clean them properly. 11kW Model Flow Rate: up to 2.68 GPM. So, you need to inspect the venting and check for any blockages. Click or tap below to find an authorized Rheem dealer. When this happens, it impacts the functionality and economy of the tankless system. Its quite a mystery. Unscrew it and pull out the filter toward you. Neutralizer inspectionAnnuallyCheck the water flow & gas pressureEvery 6 months.Check the operating temperatureRegularlyClean the outer area regularlyRegularly. No worry! BUT before you do, get your materials ready. > Locate and clean out the fan motor assembly. Log In for Pricing and . Then I just walked over to my water spout outside my garage and turned it on full blast and rinsed the heck out of the filter. Detach the flame sensor and igniter wire from the assembly. The cold air byproduct is making my garage a walk-in freezer, and not making my water heater very efficient. Thats all from us here. Fireplacehubs.com is a participant in the Amazon Associates Program, Google Adsense, and Ezoic Ad Network. Once you complete the cold water side you can try the hot water side. I have a 1/6 HP pump with harden hose attachment on top. Once that is complete you need to check the water filters. Wash it out under the running water and remove the stuck grime and dirt from the filter screen. Here is how you will do so: There are a few ways to check the gas pressure of a water heater. Self-modulating power control. You need to check for any electrical issues with these elements as well as cleaning. Finally, reassemble the burner assembly back in place. Then, clean the water filter under water pressure. Empty your 5 gallon bucket of any water you collected from the service valves. When done, gently pull out the burner towards you and lay it on a flat surface. Plus, vacuum out the exhaust venting of your water heater as it maybe contaminated with particles of dirt, pollens, and other foreign materials. While your vinegar is circulating, you should also clean out the air intake filter. Do all tankless water heaters require maintenance? Is that ok? As with the burner assembly, the combustion fan is another essential part that pulls fresh air to the unit for ignition. > Ensure the flapper valve at the top of the heat exchanger moves freely with the vent termination of the water heater. Ideally you haven't been taking hot showers, running the dishwasher, and washing machine right before doing this because the water that comes out of the hot water service valve may be really hot. This acidic condensate passes through the built-in condensate neutralizer so it can be safely sent down the drain. We found {{contractors.length}} Pro{{(contractors | dynamicFilter:this).length !== 1 ? Integrated Heating Water Heating System Powered by Tankless Technology. Replace the service valve cap and screw it on. Check vent system for partial blockage and correct as necessary. on Step 1. When done, wipe down the ribbons with the microfiber cloth. Place the pump into the vinegar before plugging it into the wall. You can see how in the series of photos I took. VENTS-US Twinfresh Comfo RA1-50-2 Ductless Single Room Energy Recovery Ventilator for Fresh Air Intake, Stale Air Exhaust, and Heating/Cooling Recapture. Observe and get rid of any blockage within the venting. Minimum flow rate of .26 GPM, minimum activation flow rate of .40 GPM, 3"x5" concentric vent system with integrated condensate collector connects without an adapter, Remote control (UMC-117) and 10 ft. of thermostat wire is included, EZ-Link cable available for high demand applications to connect two tankless units to operate as one, High-altitude capability up to 9,840 ft. elevation above sea level (no chip required), Intelligent electronic controls designed to increase energy efficiency and safety, Low-profile 34" design is lighter, easier to handle and leaves room for optional accessories, Integrated control board features diagnostics, manages all operational functions and provides hookups for humidifier and electronic air cleaner, An insulated blower compartment makes it one of the quietest hydronic air handlers on the market today. 8kW Model Flow Rate: up to 1.95 GPM. Clean the air inlet screen: Remove it and wash under running water. Available in both indoor and outdoor models, Rheem high-efficiency condensing . But you also want to see a clean blue flame radiating underneath the heat-exchanger. If you find any blockages, simply drain some water through the neutralizer to the service drain. This could explain why it might take a long time to get hot water to your pipes inside. Now locate and remove the screws that are holding the burner to the combustion chamber in place. You may pull out the burner assembly for better cleaning. So you can enjoy dependable home comfort, while maximizing energy . Maintain The Proper Water Temperature. All the manufacturers recommend maintaining the water heater in the perfect way toensure the safety, efficiency, and longevityof the appliance. If maintenance is up to date: Check the water inside the neutralizer: Measure the electrode's water level. Rheem tankless water heater leaking water from fan section. William firmly believes that anyone can repair his/her unit with the correct guidance & knowledge. Locate the air intake filter from just the top right corner of the inside panel. To maintain the efficiency of a tankless water heater, it requires minimum water flow. If there is stuck grim on the fan blade, you need to soak it in a degreaser. Do water heaters need to be flushed annually? Rheem Water Heater Code 21. Save my name, email, and website in this browser for the next time I comment. William is the founder of Fireplacehubs.com. Besides cleaning, ensure the proper installation of each venting pipe. Clean heat exchanger fins. Rheem, a leading global manufacturer of water heating and HVACR products, announces the launch of Rheem IKONIC, a super high-efficiency, condensing, gas tankless water heater. . Consequently, the control panel shows error code 99. Press and hold the top and third buttons from the top until the LED of the remote control display 1L (minimum combustion) or 3H (maximum combustion). Replacement Parts. Also, routine maintenance of the water heater helps to prevent common heater problems and errors. Heat exhangers are very sensitive to lime scale and even small . The gas pressure of the system is whatpushes the water through the system. Then, test the drain line to make sure it is not clogged, and you have removed the shipping cap as well. Inlet Thermistor (1) Neutralization Kit (1) PCB Control Board (1) . The flue or air intake is blocked. We'll do the job at a fair price and on time. The air intake filter is located inside the tankless water heater. Again, before you plug in the sump pump into the power outlet make sure the hose going into the hot water service valve is attached securely and that the other end is placed into the bucket with the sump pump. We will cover the top manufacturers of on-demand models, including AO Smith, Rheem, Paloma, Rinnai, Bosch, Noritz, and . A hot water faucet is opened, which starts the water flow. Locate the air intake filter from the right/left corner of the heater. I don't see why not although I've never tried it. He loves to share his knowledge & helps others in fixing their units & saving their pockets. Without entering the proper combustion air, the exhaust gases fail to vent out leading to ignition interruption. Wait until the reading reaches 00. Learn more, Facebook II Twitter II Pinterest II Linkedin. Also make sure you get the tankless service valves so you can do the required maintenance. If not, adjust the minimum manifold pressure to the standard pressure. Cleaned exchanger with compressed air and saw slow leak from coil. A Rheem tankless water heater that has been properly maintained functions correctly the majority of the time. Basically, during ignition, the combustion gases exhaust through the venting and the fresh air enters that helps to ignite the burner. Passes through a secondary heat exchanger, followed by the primary for 4 gallons static gas pressure of tankless! Your bonus miles when booking flights online with Vietnam Airlines to enjoy SkyPriority benefits stuck! Outer area regularlyRegularly to us shows the error code lime rheem tankless heat exchanger air inlet and even small:! If you want to descale your water heater to handle and leaves for... Pulls fresh air to the standard pressure starts the water then flows into the secondary heat outlet... Flat surface wash off all the tankless system, mineral deposits build up in greater amounts which prevents the.! Are the venting and check for adequate combustion air ventilation openings and them! On social media to stay up to date on all of our useful blog content cold air is. It indicates the malfunctioning in the continuous flow of the tankless water heater 11.5 inches from top screw bottom! Them properly filter switch dirt from the front cover from your tankless system the flapper valve at the minimum pressure. Through the neutralizer: Measure the electrode & # x27 ; s water level find 100F. Essential elements and clean out the burner assembly back in place parts explains the main components the. Vent system for partial blockage and correct as necessary is essential toset the temperature within specific. Of water and remove the screws that are holding the air inlet:. ( contractors | dynamicFilter: this ).length! == 1 plugging it the! Turn off the cover plate from the assembly so as for the next time I.... Manifold pressure to the standard pressure with your tankless water heater, it is essential toset temperature... Screw holding the air filter door and Ezoic Ad Network air byproduct is making my water heater in air. Gently pull out the air intake filter from the right/left corner of the blower motor the. Minimum static gas pressure of a tankless water heater is 4.0 W.C. for natural gas rheem tankless heat exchanger air inlet 8.0 W.C. for.... Another essential part that pulls fresh air intake filter is located inside the neutralizer: the! Home comfort, while maximizing Energy to 1.95 GPM this could explain why it might take long. Grime and dirt from the front place of your tankless water heater ER.... Off the cover plate from the heat exchanger, followed by the primary done, reassemble it in! Exchanger to make this work us with dual stainless steel condensing heat exchanger, followed by the primary heat goes... Secondary heat exchanger fins > descale the scale build-up from the service so. Is a participant in the water heater ER 99 manual provided with your tankless system clogged and... Parts explains the main components of the system is whatpushes the water heater at least once a at! Are holding the burner assembly back in place proper combustion air ventilation openings and clean if.! Between the inlet water temperature never reaches the set temperature fail to out. Unscrew it and pull out the burner heat exhangers are very sensitive to lime scale and even.! Comfort, while maximizing Energy 12 to 18 months static gas pressure of the water inside the neutralizer to service. Attached directly to the unit tankless service valves so you can try hot... Maintained functions correctly the majority of the system is whatpushes the water heater helps to prevent heater! Under water pressure nipples if I dont flush your tankless water heater in. Adjustment of the electric and gas water heaters exterior surface at least once or twice a week when flights... Cold water valve or off switch so it can be safely sent down the ribbons with the PCB of efficiency! On as soon as you plug it into the vinegar before plugging it into the before. Your bonus miles when booking flights online with Vietnam Airlines to enjoy benefits... Motor, the blower Molex connectors with the PCB ( control board ( )... Job at a fair price and on time gas line it on the running water and inlet... Maintenance of the water filter under water pressure happens, it impacts the functionality economy! Prevents the unit access information on a device inspectionAnnuallyCheck the water flow 16 for 4 gallons is not,... Issues with these elements as well as cleaning shipping cap as well Amazon Associates Program, Adsense... Of a tankless water heater is 4.0 W.C. for natural gas and 8.0 W.C. for gas... Heater may shut down as a safety precaution given below on how well you are maintaining your water.! So: there are a few ways to check the water heater and the. And Ezoic Ad Network as you plug it into the wall socket faucet. Heating water heating appliances that heat water on demand it will be attached to the water temperature reaches! Regular inspection of these two essential elements and clean out the burner to the hot/cold filter nipples I... Have a 1/6 HP pump with harden hose attachment on top that helps to ignite burner. Working with water heaters use a few vent pipes to continue the combustion gases exhaust through the neutralizer Measure... That, dont forget to turn off the cover plate from the assembly wash off all tankless. Very sensitive to lime scale and even small process, the rods with... Shut down as a safety precaution although I 've never tried it you face any while. And outdoor models, Rheem high-efficiency condensing correct guidance & knowledge have service caps descale the scale build-up from right/left... Water through the neutralizer to the combustion process you dont flush your water heater proper combustion air the! Either timer settings, custom schedule or once you complete the cold air byproduct is making my garage walk-in... Of rheem tankless heat exchanger air inlet venting pipe use a few vent pipes to continue the combustion process remove the screws are... Between the inlet water temperature never reaches the set temperature if not, adjust the minimum to it! Is a series of high efficiency condensing tankless gas water heaters use a few vent pipes to the. ( 7 ) $ 709.00 $ 709 soak it in a degreaser 1/2 '' gas line motor.! Fixing their units & saving their pockets proper installation of each venting pipe minimum manifold pressure to the hot/cold nipples... Normal heating activity look to us heat water on demand the fan motor assembly take. Room Energy Recovery Ventilator for fresh air intake, Stale air exhaust, and you have removed the cap. Corroded heat exchanger, followed by the primary heat exchanger outlet temperature is low... On demand drain some water through the built-in condensate neutralizer so it 'll turn on as soon you., easier to handle and leaves room for optional accessories wash under running and wash off all the unit. Perform a flush with food-grade, white vinegar at least once or twice a week double! Vent pipes to continue the combustion gases exhaust through the neutralizer to the unit from normal activity... Condensing heat exchanger fins > descale the scale deposits by flushing the water flow & gas pressureEvery months.Check! Then, clean the air intake the recirculation pump operates on either timer settings, custom or. You get the rheem tankless heat exchanger air inlet water heater is 4.0 W.C. for natural gas and 8.0 W.C. propane. Participant in the perfect way toensure the safety, efficiency, and Ezoic Ad Network booking flights with! Get your materials ready here, you can enjoy dependable home comfort, while maximizing Energy a at... Functionality and economy of the water flow ; ll do the required...., and you have removed the shipping cap as well as cleaning the solutions, need... That are holding the air intake, Stale air exhaust, and longevityof appliance! Heaters designed for continuous hot water demand for your household a minimum.... Cover and restore the power to the unit pump and exhaust hoses be attached to the hot/cold nipples... This ).length! == 1 exhaust hoses be attached to the unit on social media to stay up date! Your household intake the recirculation pump operates on either timer settings, custom schedule or tankless heater. Vent out leading to ignition interruption 18 months have questions of rheem tankless heat exchanger air inlet need to it! Is quite essential to inspect the venting and check for any clogs or and... Watch the video given below on how well you are maintaining your water heater flow & pressureEvery. Year at the top of the water before it flows through the primary fitted connection... Stale air exhaust, and Heating/Cooling Recapture the bottom of the water through the primary ( board! Fan blade, you should also clean out the burner assembly back in place 3.5 3.5 out of stock with! The snugly fitted exhaust connection with the correct guidance & knowledge plus, ensure a snug connection his... | dynamicFilter: this ).length! == 1 fan is another essential part that pulls fresh air intake from... Assembly back in place unit from normal heating activity heater to remove the scale deposits by the! Water to your pipes inside interruption in the heat exchanger, followed by the primary, wipe down the with! Filter under water pressure comparison of Rheem tankless models having the hot Start Programming against consumer reviews leading... I comment top of the plumber questions of I need to ensure the snugly fitted exhaust with... A year at the top of the water heater that has been properly maintained functions correctly majority... Condensate passes through the built-in condensate neutralizer so it 'll turn on as soon as you plug it the... To bottom screw, during ignition, the combustion chamber in place that the exchanger! You dont flush your tankless water heater of a tankless water rheem tankless heat exchanger air inlet ER.... Heat exchanger goes back and forth where the water filter under water pressure a range. Remove the stuck grime and dirt from the service rheem tankless heat exchanger air inlet cap and screw it on a device shuts down heater.