A plumbing system crossover where there shouldn’t be one. Services LLC Associates Program, an affiliate advertising program designed to Cold water sandwich is the situation when, for example, you turn on the shower and get warm water at first, then a blast of cold water, and warm again. Very frustrating! First, you can turn the thermostat down on the water heater. Put it back on, voila... hot water, again! It's easy to do. Took the shower head off, tapped out the aerator with a screwdriver and hammer. Cold water sandwich or hot water temperature fluctuates. Ask Your Own HVAC Question. Cleaned the burners again, but it didn't solve the problem this time. So what accounts for that intermediate burst of cold water? If neither of these factors are properly addressed, then the tankless water heater might not be able to meet the demand being placed on it and will fail to work, as its computer system will be overloaded. Unlike traditional hot water heaters using a storage tank, the tankless units have no storage tanks and thereby have no standby heat loss—the heat lost and energy wasted by heating water only to store it in a tank, a character flaw of traditional hot water heaters. Common problems with tankless waters include the cold-water sandwich phenomenon, scale and mineral build-up, blocked air supply or exhaust pipe, and ignition and flame failure. Would like to hear any good solutions. Make a seemingly simple mistake and it can easily turn into a costly disaster. by kevin So in this example, after we flushed out the insides of the tankless water heater, we put it back together properly with a brass fitting kit made for tankless water heaters. If the tankless water heater is shutting off when someone opens or closes some cold water fixture, the problem could be with the temperature regulating valves you have installed somewhere in your water line. Different brands of tankless water heaters perform differently, but in general, you will have to wait a little longer for hot water from a tankless water heater than from a traditional water heater with a tank. If water has a metallic smell or taste, there could be iron present. For showers, hot water for about 2 minutes and then it goes completely cold! It’s possible you may have an issue with the thermostat or gas control valve. after flushing a low rumble sound was noticed on the renaii hot water tankless unit. After about 5 to 10 minutes of hot water, the water temp would slowly to drop. You get a very slow gradual drop in temperature, but it doesn't drop suddenly after a few minutes like the pex solution would. Pro: Unlimited Supply of Hot Water. If you ever have your water shut off, you've got a whole tank of water available for you to use. Water stays cold. Simply click here to return to Troubleshooting. With so many wires and small parts, tankless hot water heaters can have a long list of possible problems. If the pressure does drop and you are putting a demand on the heater where it needs to draw lets what ever the BTU requirement for that draw, and its starving for gas, it will reduce the flow to give you hot enough water. However, if you’re thinking of investing in a Pocatello, ID tankless water heater installation, there are some important factors to keep in mind. My tank-less water heater goes from very hot to cold during showers and while washing dishes ect.. Now, ALL my showers are turning cold, even with good water pressure. When I go to run the hot water, it heats up but when the boiler reaches max temperature it shuts off the flame and never kicks back on again so the water then goes cold. I had this problem and found that the air intake screen was clogged with lint and dust. Soon after, the boiler turns on, and water remains hot. Concept is to use an electric tankless heater to pre-heat water going into my gas tank-type water heater. Here’s a scenario; you come home from a family beach day and everyone in the house needs to take a shower. This unit is equipped with an internal freeze protection … Choose the right model. #3. The dip tube is cheap and not terribly difficult to replace. The cold-water sandwich phenomenon. If it’s broken, cold water fills the top of the heater and begins to flow right out the hot side. Damaged flow sensor—something that should be checked during your annual plumbing maintenance appointment. I'm very confused and appreciate any suggestions. Advanced Home Services is the standard when it comes to providing great service. If mineral buildup has already occurred in your tankless water heater’s lines, then you will need a professional to clean these lines before continuing to use your water heater system. And remains that way for the rest of the shower time. water goes cold on my rinnai tankless, after 3 or 4 minutes, then gets hot then goes cold. While many backup battery systems may be compatible with tankless water heaters, the HUGO Battery Backup for Tankless Water Heaters (available on Amazon) is the only model specifically designed for use with tankless water heaters.Features like the flow sensor and complete weather-proofing make this battery backup system the best choice for people with a gas-powered tankless water heater. And for years it had worked correctly. Tankless. Some of these issues can be fixed by the homeowner, while others will require a professional HVAC technician. (los angeles, ca). The cold water will eventually turn to hot after a few minutes. Hot water runs out in the shower and faucet. He's replaced the wireing loom and fitted a new fan but the problem still exists. Show More. Hot water is a staple in your daily life, and it’s often taken for granted—until something goes wrong. Finally, another issue that homeowners often find with their tankless systems—if not properly installed and maintained—is mineral buildup. Hard water can be and is a problem for pipes—creating hard scale within them that leads to clogs and/or corrosion. If it takes more than a minute, you should contact the installer to see if there’s an opportunity to adjust the settings so that you can access hot water more quickly. Although uncommon, issues can arise if something isn’t working correctly within your water heater. The guidelines for most tank heaters recommend a water temperature of 120 degrees. Water Flow/Temperature Fluctuation Problems: If there is a low flow from the heater, the first thing to check would be the input filter. There’s nothing to worry about. Corroded lines—corrosion can occur due to condensation dripping onto the gas burner, or a poorly installed heat exchanger. He's checked the pump and it's running ok. When the shower is running cold, the sinks upstairs are still running hot. tried flushing with vinegar, cleaned the filter and checked for dust and bugs. With the lower gas pressure, the water heater will reduce the water flow so it can meet the selected output temperature. Cold Water Sandwich; Air Supply or Exhaust Blockage Message; No Ignition Message; Flame Failure Message ; Pipe Issues; In addition, look for these telltale signs of water heater failure: Changes in water quality. Jun 22, 2018 Rating: Water turning cold in one shower by: Dwhit70 I would bet the shower head is clogged up enough to mess with the flow. A tankless is a cold device until its used. A few minutes later, a second tap is opened, and the hot water still in the line from the previous use flows out, but then there is a short spurt of cold water as the heater begins to reheat the water again. These valves automatically change Your tankless water heater will feel cold to the touch when the heater unit and pumps are in the rest state and not heating water. I am having the same problem. A few years ago we installed a tankless hot water heater and we love it. Your tankless water heater will feel cold to the touch when the heater unit and pumps are in the rest state and not heating water. Does anybody have any idea what might be causing this problem, and if it's something fixable?? Another problem that tankless water heaters can run into is that of a cold water sandwich—a plumbing term given to sudden temperature fluctuations, when your tankless water heater produces hot and cold water intermittently. I commented before as anonymous, re: only 1 shower turning cold in middle. Unusual odors. Category: Plumbing. Worked fine for 6 months until I flushed the system with vinegar to clean. Today’s gas water heaters have air inlet screens at the bottom of the water heater that can get clogged with dust, dirt, soot, cat hair, lint, etc. If you see chunks of sediment, or water appears cloudy or rusty. Satisfied … Takagi T-K4-IN-NG Tankless Water Heater. ID That, is a cold-water sandwich and can be highly annoying. A tepid or cold stream of water may be an indication that your water heater is not set to the right temperature. If this is the problem, then there are really 2 solutions here. If not, you should also check the error code displayed on the heater, and look it up to see what is happening with your Navien heater. Tankless water heaters are a great investment for your home or office. It worked great for another 3 years and then started having the same problem. it took a couple minutes, but went away. Lowering it enough sometimes that it won’t trigger the water heater. When your Titan water heater is producing hot water which all of the sudden turns cold and back to hot; the first thing to check is whether a mixing valve in the faucet is defective creating a water … Switching from a tank-style water heater to a tankless water heater will save a family of four an average of $100 per year or over $1500 throughout the lifetime of the system, according to Energy Star. If you live in a cold climate like Massachusetts and are looking for a tankless water heater, go gas. When your Titan water heater is producing hot water which all of the sudden turns cold and back to hot; the first thing to check is whether a mixing valve in the faucet is defective creating a water return. Wondering if it’s failed flow sensor?? Just turn it on a little & not wide open just 1/4 of the way. There’s nothing to worry about. Maintenance is the best preventive measure you can take to avoid the above-mentioned issues that could otherwise occur with your tankless water heater. 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