There are 2 factors that strongly affect whether the tankless water heater can keep up in a cold climate: Fuel type (electric vs. gas) Size; Why the tankless water heater’s fuel type matters. If your hot water heater is a little cold, you can try warming it up by covering it with a blanket. The flow is too low to keep it going. Plumber: Mario, Master Plumber replied 11 years ago. Do a load of laundry while you’re taking a shower and a tankless heater will have a hard time producing enough hot water to supply both. Few years ago, when the awesome tankless water heaters of today were not available, not a day used to pass without someone complaining about a tankless water heater going cold … We often recommend the installation of a tankless water heater to our customers who are looking to have a new water heater system put in, either as the first water heater for a house or as a replacement for an aging tank water heater.There are numerous advantages to using a tankless water heater, such as lower energy bills, longer equipment life, and unlimited hot water … Rinnai Tankless Water Heater Troubleshooting Manual WARNING There are a number of live tests that are required when fault finding this product. Lee has over two decades of hands-on experience remodeling, fixing, and improving homes, and has been providing home improvement advice for over 12 years. Remove the handle adapter with the Phillips head screwdriver. All Rights Reserved. In all cases, tankless water heaters must be property vented. If you have a tankless heater, you have to keep in mind that it’s not uncommon for the water inside of it to go cold at times. This problem happens because the heat exchanger (the part that actually heats the water) takes a while to warm up. Do a load of laundry while you’re taking a shower and a tankless heater will have a hard time producing enough hot water to supply both. Tankless heaters are initiated by flow demand. Vent pipes may be blocked by nests, vermin, or other debris, affecting the heater's ability to operate. What is the best gas tankless water heater? My tank-less water heater goes from very hot to cold during showers and while washing dishes ect.. First off, this is a common tankless problem called a “cold water sandwich”. While a lot of people simply give up at this point, it’s important to acknowledge that there is absolutely no need to give up on your heater just because it’s not heating properly. Replacing the shower cartridge is often the best way to fix inconsistent water temperatures, as indicated below. Rather than dealing with this problem, be sure to beware of the different reasons to ensure it doesn’t happen again. This is when the water heater fluctuates between putting out hot water and then cold water and then back to hot water, etc. Install the scald guard and adjust it while the water is running. The water heater also mixes the hot water it makes with cold water … water turns cold after 5 minutes then hot again later. But regardless of the climate or the size of the unit, a tankless water heater is not recommended for households that have a very high hot water … If you keep it on a strong flow of completely hot water, it is fine but if you add cold or slow the amount of hot water it goes cold. Two water demands have been placed on the system back-to-back. One of the primary ways that a tankless heater creates heat is by the vibrations in the electric coils. The other dip tube is shorter and it draws hot water from the top of the tank since hot water rises. Since the system is central to all of your home's services, all must share both the cold and hot water. In most cases, a tankless on-demand water heater fails to supply enough hot water if the unit is too small. Use the pipe wrench to turn the dip tube fitting off. Use a descaler cleaning kit every 12 to 18 months to rid the system of mineral deposits. When a dishwasher turns on or a toilet is flushed, there is a new demand for water placed on the system. Remove the copper fitting and set it aside. Either space out the water demands or replace your current heater with an on-demand water heater with greater output. Carbonates, rust, oxides, and other mineral deposits may be hampering the heater's ability to heat the water. When it is free, use your hands to pull the dip tube straight up and out of the water heater. 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. Tankless water heaters provide steady hot water on demand. One dip tube extends almost to the bottom of the tank and forces cold water to the bottom. Why You Get Cold Water. The need for hot water can quickly outstrip on-demand water heaters' supply. See how to repair a tankless heater when there is no hot water, water is too hot, there is not enough hot water, the pressure is low, cold water sandwich (the temperature of water fluctuates: hot-cold-hot), the gas burner doesn’t ignite, and what to do if there is an error code. Ask Your Own Plumbing Question. At a rate of approximately 1.6 gallons per minute the water reaches the temperature set by the home owners. You have a tankless hot water heater because you don’t ever want to be without hot water. You can go a long way to properly invest in the necessary equipment that makes the heater work, and if it does, you’ll notice very quickly that the coils are recalibrating, ensuring that the proper electrical connection established. Introducing "One Thing": A New Video Series. 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. The flow rate for tankless water heaters is measured in gallons per minute of hot water the machine can produce. Gently pull out the metal clip holding the cartridge in place. Also, even when the water comes out the well properly, that’s still a long way to go until it … After about 5 to 10 minutes of hot water, When this happens, you likely have an issue with the fuel source. My Navien tankless hot water heater goes hot and cold in the shower. This is absolutely vital to make sure the connection works, otherwise, you’re going to see long-term damage from start to finish. Not the type of blanket you would use to stay warm, but a specially-made wrapping that covers the hot water heater. If your tankless water heater seems to run out of hot water giving you a cold shower, you may be experiencing the "cold water sandwich". 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. My water pressure is good and my filters are all - Answered by a verified Plumber ... it will not allow the flow to move fast enoughf to trip the sensor causing the unit go on and off on and off making the water go hot and cold hot and cold. Use the copper pipe cutter or hacksaw to cut the copper pipe about 8 inches above the water heater. Copyright © 2021 Rooter Guard. Showering under comfortable warm water that unexpectedly turns cold is a rude awakening. The Recirculation Pump Commonly known as a circulator pump, this system is responsible for circulating water from and back to the heater, creating a reheating process to ensure hot water. The tankless water heater burner switches off and cold water moves through your shower line. Remove the handle with the correctly sized Allen wrench. On-demand water heaters, or tankless water heaters, are energy-savers since they do not heat a large amount of water (often over 55 gallons) to be held in reserve for whenever it is needed. But there are multiple possibilities for why it’s happening, so it’s vital that you stay abreast of the various reasons, otherwise, you’re going to see very quickly that your water heater is going to be rendered ineffective for the long haul. When this happens, incoming cold water mixes with hot water and the result is inconsistent temperatures or sometimes entirely lukewarm water. I bought a Marey, it went cold after 5 min. Yes, gas tankless water heaters can work well, even in cold climates, as long as the unit has been sized correctly to meet the hot water needs of your particular household. If the water heater can’t get fuel, it can’t ignite and warm your water … if the screen gets gunked up it will not allow the flow to move fast enoughf to trip the sensor causing the unit go on and off on and off making the water go hot and cold hot and cold. And when that water reaches high enough temperatures to scald, it is dangerous. Many homeowners have recently turned to tankless water heaters. Complete on-demand water heater descaling kit with solution, bucket, hoses, and pump. Examine and clean out all vents that extend to the home's exterior. But there are steps to take to fix any temperature inconsistencies. What does Consumer Reports say about tankless water heaters? Gas units typically heat water faster than electric ones. I don't like the idea of wasting all that cold water, so rather than starting with the shower, I'll use the sink first and try to make use of the cold water while waiting for the hot. On top of your water heater are two pipes that extend into the water heater. Marey says you can use only hot water if you add cold, it turns off the heater, so you get cold water. Tankless heaters are energy efficient and popular for many homeowners. Before it fully warms up and starts heating the water, you get a short run of cold water. The water heater also mixes the hot water it makes with cold water to give you the temperature you … If this is happening, you’re simply going to have to wait until the temperatures get back to a normal level. Devices Required for the Recirculation System In a cold climate, the first water heater tips to consider is to size tankless units properly, says Linda Cahill, vice president of Tankless Concepts, in Falls Church, Virginia, which sells and installs Rinnai and Navien products. Slide the new cartridge in place, with its hot side on the left. Water heaters with a tank drum store pre-heated water. Water goes cold on my rinnai tankless, after 3 or 4 minutes, then gets hot then goes cold. Yet pressure-balanced and thermostatic shower/tub controls are designed to counteract that problem. Here's how. by kevin (los angeles, ca) In one shower, the hot water lasts about 5 minutes and then turns cold. If I turn off the shower or just wait with the cold water running, about 5 minutes later it is hot again. Unfortunately, they may be prone to temperature fluctuations which are caused by cold water slipping through the system when the heater is switching modes. This is one of the biggest issues that these kinds of heaters have, but if you’re aware of it before it happens, you can reduce the chances that something of this sort of nature would happen. Tankless water heaters use a condenser that pre-heats the water, so it doesn’t take as long for the water to reach the pre-set temperatures for hot water flow. Benefits: A tankless water heater has a flow switch in that water heater, and you’ve got to have so much flow going through that water heater for that water heater to kick on. It's frustrating to draw what you believe to be cool water from a tap, only to find warm water flowing into your drinking glass. Privacy Policy. You have 2 fuel choices when it comes to tankless water heaters: Gas; Electric; But electric tankless water heaters, like electric tank water heaters, struggle to heat water quickly. The cold water can be faulty in several ways: It can snap off entirely at any place or it can be cracked, corroded, or develop holes at any point in his length. Slide the new dip tube straight down into the water heater. The Heater Won’t Turn On Tankless water heaters provide hot water on-demand. Plumbing Errors:– Due to dislocations in the plumbing fixtures the hot water flow can be restricted. When your tankless hot water heater is running cold, it’s time to investigate. However, for this to work, you need a steady power connection, otherwise, it’s simply not going to work. On top of your water heater are two pipes that extend into the water heater. Inconsistent Shower or Bathtub Water Temperature Only, Faulty Water Heater Dip Tube Causing Inconsistent Temperatures, Inconsistent Water Temperatures With On-Demand Water Heaters, How to Troubleshoot and Repair an Electric Water Heater, How PEX Pipes Can Help You Do Your Own Plumbing, An Introduction to Tankless Water Heaters, The 9 Best Tankless Water Heaters of 2020, How to Replace a Heating Element in an Electric Water Heater, How to Repair a Moen Pressure-Balanced Shower Valve, How to Replace a Mobile Home Water Heater, How to Repair a Leaky Single-Handle Cartridge Faucet, How to Install a Reverse Osmosis Water Filtration System, Reasons Why a Water Heater Doesn't Make Enough Hot Water, Easy Kitchen Plumbing Projects You Can Do Yourself. Water Heaters - Water go cold after 10 minutes with a tankless water system - Hi, I have a 2 year old Rinnai thankless water heater in an equally old house. My bathroom is pretty far away from my water heater, so it might take 30-60 seconds to get hot water from the tap. Why should I buy a tankless water heater? Can I buy a Rinnai tankless water heater at Lowe’s or Home Depot? Extreme care should be used at all times to avoid contact with energized components inside the furnace. If this is happening, you’re simply going to … Because simply put, they are not going to improve just because you want them to. Low water pressure:– Due to lower flow rate. tried flushing with vinegar, - Answered by a verified Plumber We use cookies to give you the best possible experience on our website. Simply going to work a toilet is flushed, there is a staple in your 's... The fuel source tankless heater is the cold and hot water rises are. Heaters are energy efficient and popular for many homeowners have recently turned to tankless water heater the. With this problem, be sure to beware of the wrenches electric.! 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