Pump cyles on/off rapidly

Discussion in 'Pumps and Tanks Well Forum & Blog' started by gizmodiy, Sep 30, 2013.

  1. gizmodiy

    gizmodiy New Member

    Messages:
    14
    Location:
    Toronto, ON
    My 1/2 hp jet pump starts/stops several times in rapid succession after I recently moved the red lion RL20 20 gal pre-charged pressure tank. This is a cottage application where the jet pump draws water from the lake. Prior to moving the pressure tank, the tank and the pump were about 80' from the lake with vertical height of about 8' and only a few feet from each other. There is a 1" poly pipe from the lake to the pump. Everything was working well before moving the pressure tank.

    I moved the tank as the first and temporary step in installing a winter water system. The pump remained at 80' and the tank now sits at 116' and about another 5 feet higher. In addition, there is now a check valve between and near the tank and the pump. The foot valve remains in the lake. I know its weird to have a check valve here but as I say its a temporary step until I get a submersible pump installed in a few weeks. There is 1/2" poly between the pump and the pressure tank. As I say, after I made this change the pump goes on/off in rapid succession several times them stops. I am getting pressure but it at the low end. If I run water it does it all over again.

    The research I've done tells me that my problem could be the now larger distance between the pump and tank. However, I've also moved the tank higher. I'm trying to avoid getting a larger pressure tank because its hard to accommodate its larger size. Will moving the jet pump to 116' with the tank solve the issue, or do I need a new pressure tank? Would an undersized pressure tank by this margin cause this?

    Any thoughts as to what could be the problem here?
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,841
    Location:
    NW Ontario, Canada
    Move the pressure switch close to the tank.
  3. gizmodiy

    gizmodiy New Member

    Messages:
    14
    Location:
    Toronto, ON
    Thank you. I will give it a try.

    Given that I move the pump and pressure tank from 80' to 116' fed with 1" poly from the lake, is the tank big enough at 20 Gal? What is the experience if its not? Will it re-cycle rapidly, or will it just pump more frequently? The dwelling has 1 toilet, 1 shower, 1 bathroom sink, 1 kitchen sink and 1 dishwasher that runs once every couple of days.
  4. valveman

    valveman Moderator Staff Member

    Messages:
    4,388
    Location:
    Lubbock, Texas
    As LL says you need to get the pressure switch on the other side of that check valve and as close to the pressure tank as you can get it.

    A 20 gallon tank only holds 5 gallons of water. A bigger tank can’t stop cycling, it can only reduce the number of cycles somewhat. A Cycle Stop Valve does stop cycling, then the 20 gallon tank is plenty or you can use as small as a 4.5 gallon tank since space is an issue.
  5. gizmodiy

    gizmodiy New Member

    Messages:
    14
    Location:
    Toronto, ON
    That was it! It makes so much sense in retrospect (doesn't it always!). Once I moved the pressure switch to the other side of the check valve and moved the pump close to the pressure tank it was working perfect!

    Thank you LL and Valveman. Great diagnostics and advice.
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