Mitsubishi internal lift pumps

[moondawn]

Hi, I was servicing the other day and found a one way blow on a city multi leaking water out the front cover. Filters were clogged cleaned them, I took down the fascia cover and then removed drip tray which had a fair amount of water inside.
I checked the internal pump for kinks in the outlet hose and tested with a cup of water. The pump took half a cup of water when pushed up to the pump. Could not take more as cup would not allow. When I dropped the cup down the pump was still pumping but all the contents it had took all dropped back in the cup.
I decided to remove the outlet from the pump and blew co2 through to remove any blockages.
I checked the unit was level and that the pump lift was not out of range, was well within 500mm.
tested with the cup again and got the same scenario.
I was thinking the pump is not operating correctly what do you guys think?

Cheers

[install monkey]

the lift pump is purely a spinning paddle- the volume of water it sucked out ur cup will fall back out when you move the cup, best method for testing is take the side panel off where the flare connections are, stop the fan and pour a jug of water in, to proove the water is emptying- pump runs all the time in cooling so there will always be water in the tray once it has reached a certain level- it was probably just freezing up due to dirty filters

[moondawn]

hi install, yeah i was not convinced fully but to be honest not completly sure how the operate. i thought that if the pump is pumping should the half cup not be on its way through the pipework. i guess the clogged filters could have caused this problem. my best way would of been to pour water in the unit and undo the brass connector however its plasterboard ceiling and was no told not to cut into it. so thought would test the pump with the cup of water.


cheers

[install monkey]

drop the facia and leave the drip tray in place,then pour a few milkbottles of water in to prove it clears

[moondawn]

yeah will do that next time thought these pumps would be easy enough to test with cup of water but seems i may be wrong with a faulty pump. its not too late the pumps not ordered or fitted.

cheers

[JoeAT50A]

I checked the unit was level and that the pump lift was not out of range, was well within 500mm.

Just in case :- not 500 mm (600 mm in spec) measure from ceiling surface.

drain for PMFY1.jpg

[moondawn]

hi joe the height does not seem a problem it was well within 500mm and that was from the internal pump paddle to the top of drain think was around 400mm from memory.

cheers

[install monkey]

also the drain off the unit must be 3/4 overflow pipe or abs- if larger diameter then there's increased head to pump against so the maximum lift is reduced

[JoeAT50A]

hi joe the height does not seem a problem it was well within 500mm and that was from the internal pump paddle to the top of drain think was around 400mm from memory. cheers

That's Ok. Sometime many marginal issues with manufacturers' spec then hard to pin point.
By the way is there any error code? 2500...2502...2503 and so on.

[moondawn]

hi joe yeah always best to check i may well have missed that but it is fine. there was no error codes on the controller or on the g50 controller.

the drain off the units is 22m copper so its not been upsized.
cheers