18 months old an is only used for a shower and bum gun, problem is, when shower [or other] it just keeps cycling,

Its gravity fed,and pumps from the top floor to the 1st floor, so it doesnt have to work hard,

What ive done so far,

Made sure the in and out pipes are clean, removed the 8 screw valve top, checked the seating of the non return valve, although i dont think its needed in a gravity fed pump,

Removed the nitrogen sealed cannister, shook the water out of it, then blew into it, it sorta blew back when i stopped blowing so i presume the diaphragm is not leaking,

Removed and stripped the pressure cut off valve, nothing un-toward inside, although the electric side of it is sealed and cant be got at,,

Removed the impeller cover, no scoring and no up and down play in motor or side play,

Other stuff, normally,if the tank runs out, the pump keeps going at normal speed, i turn it off till we have water again, Now if i turn off the water it just keeps cycling,,

With the water on, and shower going, it just cycles,turn the shower off, it will cycle till it builds up pressure,then it runs normal till the pressure stops it,

The fact that it cycles with no water makes me think it isnt the pressure valve, The cycles are about a start and stop every second,

Help much appreciated, Thanks, Lickey..

Short cycling like that is usually a sign of no air in the pressure tank, but it sounds like you've got that one covered

Lickey

we have 2 of the same Mitsubishi pumps

the 205 is for the interior of the house & will cycle every 2-3 seconds unless we blast the water & not run it at a trickle(not optimal for the bum gun!) If your tank runs out of water the pump will continue to pump till shut down & water is refilled.Had that happen twice. Pump gets ultra hot & not to happy about it. Thank God the Mitsubishi pumps are sherman tanks! I messed with the pressure valve setting & it didn't seem to make much difference - even after Numchai did repairs & reset the setting it was the same.

The only way to fix the cycling problem I know of is to have an external tank that you pump air into & top it up every now & then If you are using the EP variety of pumps. I was going to weld a beer keg & make a pressure settup but never got around to it. They do make a unit you can add although it is kind of pricey. The other way would be to rig up a bladder setup. Info from Mitsubishi, but that turned out to be 1500 baht less than a new bladder style pump. I think Kamalabob (sorry for the incorrect spelling Bob) Had a picture under members houses with the external air tank setup if it is still posted. any airtite container with a tire valve going to the water tank would keep air in the system. Unfortunately with the EP series pump this is a known issue cause of no bladder. I hope it helps.

Barry