(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 14 of 14

Thread: Recirculation pump problems?

Hybrid View

  1. #1

    Default Recirculation pump problems?

    Hello,

    We have dual water heaters (parallel) in the basement with a separate hot water return line and a recirculation pump. When the pump is on, there is instant hot water and everything works fine. When the pump is off, there is an acceptable delay of 30-60 seconds on most faucets in the morning. The kitchen faucet and two other faucets, however, can take upwards of 7 minutes to get hot water. This can happen both in the morning and also later in the day.

    We looked for a malfunctioning check valve or cross-connection, but my plumber states everything is working fine. He said to just keep the pump on as the kitchen and other slow faucets may just be at the end of the return loop.

    He may be right, but I don't understand why almost all the other faucets would get hot water in under a minute, and the others (one upstairs, one in kitchen and one in the basement) all take such an exceptionally long period of time to get hot. I don't have a problem with having the pump on (there is a timer), but I just want to make sure that the pump isn't covering up some other problem.

    Anything else we can check?

    thanks,
    nishan

  2. #2
    In the Trades Gary Swart's Avatar
    Join Date
    Sep 2004
    Location
    Yakima WA
    Posts
    7,246

    Default

    Is there a recirculating line from the kitchen supply line? I have a recirculating pump too, and there is no return line from the kitchen supply. I knew when I installed that there would be a little more delay to this area and I am considering putting a return line in. My bathroom basin and shower at the far end of the line have virtually instant hot water, but that's where the return line begins.

  3. #3
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,653

    Default circulation

    A properly designed circulation loop, assuming the structure's layout allows it, would have all the hot water using appliances in a continuous loop from the heater back to the pump at the heater. Any fixtures not on that loop will not have "instant" hot water, but will still have to evacuate the cooled water from the pipe back to the nearest "hot" water pipe. That is apparently your situation with those faucets and correcting the problem may be costly, again depending on how your building is constructed.

  4. #4

    Default

    HJ/Gary,

    Thanks for your replies, but I think I may have been a bit unclear. There is a return line from the kitchen and the hot water works fine when the recirculation pump is turned ON. My question was why just a few faucets take an extremely long time (5-7 minutes) for hot water when the pump is off. All the other faucets work fine when the pump is off (<1 minute).

    My general understanding is that the return line should run from the furthest fixture back to the heater. Looking at my system last night, I saw that a fixture in a room adjacent to the water heater is plumbed to the return line instead of the outgoing hot water line. This is one of the three fixtures that has the long wait for hot water. So instead of a return line running from the furthest fixture, everything is run in a true loop. The last fixture is only a few feet from the water heater but is being fed via all the other copper in the house. Now it makes sense why the wait is so long without the pump, and I suspect the other two faucets are plumbed the same way (I can't check though). Is this a standard way of plumbing a return line, or some creative solution.

  5. #5
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,653

    Default pump

    Now that you have explained it better, the cause is clear. You either have or should have a check valve at the pump. If you have one it is defective so the cold water in the line and from the bottom of the tank is flowing back through the circulation pipe and since the sink and probably those other faucets are near the point where that pipe starts, they get the cold water. And it will continue until such time as the regular hot water can fill the normal piping. But since you are getting a lot of backflow, the hot water takes a lot longer to get to the faucet. Replace or install a check valve and everything will be back to normal.

  6. #6

    Default

    HJ,

    That's exactly what I thought, but the plumber said the check valves are fine.

    Also, in addition to the check valves, there are shut off valves on both sides of the pump on the return line. Closing those valves should prevent any backflow, but it didn't make a difference.

    Any ideas?

    thanks,
    nishan

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •