I just had a tankless water heater installed and I noticed that although it's recommend by the manufacturer, the installer did not add a shutoff to the hot water outlet. Will this cause any problems when flushing the system? It seems like the pump used during flushing might not be able to build up as much pressure within the unit itself if water is allowed to flow out. Not to mention the possibility of any loosened sediment getting pushed up instead of flushed.

  • Was the installer a licensed plumber? Did they pull a permit? Was it inspected (and were you there for the inspection) ?
    – Z4-tier
    Mar 23, 2021 at 3:27
  • The installer works for a fairly large company that only employs licensed technicians. I will say that I'm not sure about the permit and I don't believe it was inspected by a third party. It does seem based on a quick skimming of local codes that a permit may have been required given that the previous unit was not tankless. Mar 23, 2021 at 3:42

1 Answer 1


The first thing I would do is check if a permit is required for this job. You can look in the plumbing code for your city, but it would probably be faster and easier to just call the inspections department and ask them (and then you'll be 100% sure). If the work required a permit, find out if the installer pulled one (and check your invoice to see if you were billed for it). Also confirm if it required an inspection (some work does, some doesn't).

  • If a permit was required but not pulled, get on the phone with someone at the company and figure out why. This needs to be done urgently and they should treat it as an urgent problem. Do not wait and see, do this immediately, while you still have the option to stop payment on the check (the absolute last option, but one you want to have available just in case). Press them hard and don't let up until they fix it.
  • If a permit was required and one was pulled, first call the manufacturer and explain the installation to them. Send some pictures in an email if necessary. They will clarify exactly what is recommended. Next, get in contact with someone at the inspections department that deals with plumbing. Explain your concerns and see what they have to say. Usually inspectors want to see things installed in accordance with manufacturers instructions, at a minimum. Any deviation will generally need to go above and beyond what is called for; leaving out a valve that is specified in the instructions doesn't do that.

At the end of the day, you need to comply with the inspector, and the best way to do that is to make sure the manufacturers instructions were followed. This will also be an issue down the road if you ever need warranty service on the unit, so get it sorted out ASAP.

  • 1
    It was inspected the next week and they came back the following day added the shutoff. Apr 19, 2021 at 13:32
  • 1
    Awesome, thank you for the follow-up. This is a really good example of "trust, but verify" (ie. trust the plumber to install it, but read the directions yourself, just in case).
    – Z4-tier
    Apr 19, 2021 at 13:42
  • Exactly. They said when they came out to fix it is this is the first time they remember anyone reading the manual. I also drained the unit before they got there to save them time, which apparently also never happens. Apr 19, 2021 at 16:12

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