(Another) Water Pump Question (But Unusual)

[tamada]

KP could be onto something with the OP's 105 (100 W) pump being undersized for the house it is supplying. We had a 155 (150 W) for the best part of fifteen years until the steel pressure tank sprung a pinhole leak. I replaced it with a 205 (200 W) for our 4-bed. 3-bath, single-level home. Runs continuous when an external hose pipe is opened, but cycles at around 30 seconds (off 30 sec, on 5 sec) when a shower, kitchen sink or washing machine is running.

Not at all sure on how the OP's water supply is configured. I have city water filling storage tanks and the pump is on the outlet side of this water storage to provide pressurised supply to the house. The city water supply pressure has no influence on the house supply as it is buffered by the storage tanks.

[glalt]

Most water pump tanks do not have an air bladder inside. The air inside is gradually absorbed into the water. When that happen the tank becomes waterlogged and the pump will telegraph. Meaning it will cycle on and off every time a tap is opened. Those tanks have a plug that can be removed and the tank drained. Shut off the power and drain the tank. That will give it a new air head and the pump will again function properly. You must drain that tank every couple months. Tanks with an air bladder don't have this problem.

While that advice may be what your particular pump requires, I have had pumps here working for over 15 years and NEVER DRAINED them using that procedure.Mine are ALL Mitsubishi Pumps, in the course of 22 years changed pressure switch and the octaganal thingy on two`of my four pumps , anything else was once a tank dried out and screwed up the pump running dry. The trick aprt from cleaning out the ants , rubbish etc, is to ensure a good flow of water all the time . Ap[art from that nary a problem. I CONSIDER changing only two of my four pumps in 22 years not too bad, the well one is original 20 years and only once stopped due to a pipe coming pout oif the ground clogging up.

Moral is never BUY cheap pumps, may sound stuffy but pays for itself in the end

Better quality water pumps have what they call an air injector. If that little device works properly, it will maintain the tank air head. My ITC brand pump has this device but apparently it no longer does the job. I don't know how to repair or replace it so I bought a separate bladder storage tank. It is larger than the pump tank so the pump cycles less than it did after draining the tank.

[kopkei]

again , open the pressure switch and adjust the central screw by turning counter clockwise , and remember how many half turns you adjust ,so you can always restore the original settings ...when the pump runs without tiktacking (on/off,on/off ), your job is done , only check if the pump also stops after closing all valves , if this does not work meaning there is another problem ....and you can always restore the original setting , no harm done ...

the model of your mitsu can be a little different but same system with middle screw to adjust ....