Low flow situation with GSW John Wood

Discussion in 'Water Heater Forum, Tanks' started by LLigetfa, Jul 1, 2011.

  1. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,080
    Location:
    NW Ontario, Canada
    I've got a rental tank - gas - power vent - 6G40NVH-FV-02 - B4743 http://www.gswpartsonline.com/model/27345

    It seems to have some sort of device in it that limits flow. I think it is some energy saving anti-perc valve but looking at the parts list linked above, cannot see any such thing listed. Under normal conditions, whenever hot water is drawn I can hear something clunking in the tank.

    Anyway... yesterday I shut off the water to the house to clean/replace some filters. I didn't drain the HWT nor the lines after the softener. I did drain/flush the precip tank on the iron filter. Invariably some air does get into the house plumbing which may stir up some iron sediment.

    Afterwards, I flushed out the cold water lines and drained off a tiny amount of sediment from the bottom of the HWT to make sure the water ran clear. The last thing I want is for the wife to have anything short of crystal clear water in her soaker tub. I systematically go from nearest faucet to furthest faucet purging first the cold lines and then repeat with the hot. The only one I didn't do is the tub filler because I'd have to wash out the tub if any water were to splash onto the surface. Throughout this purging, I did not notice the limited flow on the hot side since all the other fixtures are themselves flow restricted.

    My confidence that her bathing experience would be without incident, was shattered when she turned on the tub filler. Keep in mind this is a large soaker tub and as such the tub filler has full bore valves... no pressure balance spool, no flow restrictor of any kind. The cold side ran full bore as usual but the hot side was but a fraction of the bore.

    I was finally able to restore the flow by repeatedly opening and closing the whole house draincock in the crawlspace until i finally heard that familair clunking again from the HWT. Anyone know what and where the source of the clunking is and if in fact it could be the source of the flow restriction? If so, can it be removed?
  2. Jerome2877

    Jerome2877 In the Trades

    Messages:
    397
    Location:
    BC
    There are two plastic check valves in the inlet and outlet to the tank. Yes they can be removed, just remove the hot and cold connections and pull them out with needle nose pliers.
  3. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,080
    Location:
    NW Ontario, Canada
  4. Jerome2877

    Jerome2877 In the Trades

    Messages:
    397
    Location:
    BC
    They do come out, Its a common problem. I have removed lots of them.
  5. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States

    just replace the 2 nipples with brass nipples
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