Just moved into my house and found that when you turn the cold water on (at any cold water outlet such as faucets, tubs, outdoor water hose and even the toilet), the water comes out hot for approx 10 second and then turn to cold. There isn't a hot water circulating pump or crossed piping connections that I can find. I haven't had a plumber look at it yet but I can't find anyone handy that has ever heard of such a problem. Is this something common or does it sound like a serious problem. Please let me know what you think.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Did you do back flow? Suggest you perform back wash via the hot water outlet of your heater by plugging a hose. What is the tubing size that flows thru the heating elements? If it's small, maybe you need to apply higher back pressure to remove the soil. Does it have a built in pump? If it has, check the ******* strainer, maybe it's cloaked up with debris, you never know what's in the line.
when he soldered the connections on these pipes.. he may have partially blocked the flow with solder inside..if its restricted up to 50% then its a hell of a pressure loss..hot water is always lower in pressure anyway..also take the shower head and dunk in a clr solution it may have calcium deposits inside the small plastic orafices in it..
Since no tap gets hot water, chances are good the problem lies in the hot water pipes between the water heater to the first Tee. Look for sediment lodged in water heater hot water pipe. Or sediment lodged in elbow or Tee.
Other problems can be in play. Faulty check valve or mixing valve if these are installed. Faulty recirculation system if this is installed. Also crossover at single-handled faucet where the cartridge is bad and lets the cold water flow into hot water pipe whenever another faucet is turned on. If you are getting cold water out the hot tap, and you know the hot water heater has hot water, then crossover is suspect > in addition to sediment blockage at hot water heater.
Upvote the help. And take advantage of fixya expert assistance live. For a price, expert works with you while you work on timer or any do-it-yourself project. Fixya is always less expensive than a service call.
COLD MIX, HEATER DEACTIVATES If inlet water temperature is over 70°F due to geographic location, water maybe very hot out of the tap. This requires a lot of cold water to be added with it in order to attain a useable hot water temperature. The addition of too much cold water will overpower hot water demand from the tankless water heater. This slows the flow within the tankless water heater, decreasing it below activation point, which shuts off the heater. The end result is nothing but cold water coming out of the outlet. See: TWH E2-04 Overcoming fluctuating temperatures [PDF].
FLUCTUATING WATER PRESSURE If the water pressure in the home is erratic and the water flow is not consistent while a tap is opened, then the temperature of hot water will fluctuate. The minimum water pressure for the home should be 30psi or greater. For people on well systems the minimum pressure range is 30-50psi. The use of a pressure reducing/regulating valve is an effective way to maintain constant water pressure to the water heater. Watts brand 25AUB- ¾" or N35B-¾" pressure reducing/regulating valves or equivalent is suggested.
CHANGING FLOW RATE Major changes in flow rate can adversely affect the output water temperature of the heater. Increases from one major fixture running to multiple fixtures running at one time can cause the temperature to fluctuate. Stay within the heater's specifications. See: TWH E2-03 Outlet temperature vs. flow rate [PDF].
You should check the inlet filter. Most (if not all) tankless heaters on the market have a small wye strainer on the inlet cold water connection. If debris build up in this, the water flow will be restricted.
Other than that, I'd check aerators at your fixtures, and if possible check the outlet pressure on the hot side of the tankless. If you have isolation valves, you can just run the water straight through. If the flow is restricted at the tankless, then you know the problem is in the heater or in the cold water supply. If the water flows quickly out of the tankless, then your problem is a clog in the water system after the heater.
A fault often found with these units is due to insufficient water flow. Usually this causes specifically the shower to run hot and cold. Try turning on more than one hot supply; if this fixxes the fault you will need to try and increase water flow. Most new tapware/showerware have water flow restictors built in. These are the cause of many problems with continous flow heaters such as the Rinnai. In taps they are usually located in the spout if it unscrews. In showers try the shower hose. Find them and take them out. Also make sure your mains supply to the house is on full.
There are more technical faults but this is something you can easily try first.
you probably had debris get into the filter or flow sensor when the water was turned back on. I'd recommend checking the filter first and if that doesn't work, call Noritz Tech support to help you with the flow sensor.
the filter is a black plug located on the cold water line (labeled cold on the bottom of the unit). It points torwards the left.
Slower the flow hotter the water is how it works . Sounds like the water section is blocked and could well need cleaning out . Draw back with this system is you need a good inlet flow and flow will drop when you open other taps . they are good for a small house a family house not that good . Not much you can do put in a bigger water inlet to heater ?