ATA 38    Water & waste

1 - Watercompressor failure: Check the fill/overflow valve too. 737-6/7/8/900

2 - All toilet flush systems inop ? Check servicing ball valve.  737-6/7/8/900

3 - Fwd galley drain blockage. 737-6/7/8/900

4 - No rinse water during toilet operation. 737-6/7/8/900 

5 - New dirty job man fixes all your toilet problems. 737-ALL

        1 - Watercompressor failure: Check the fill/overflow valve too. 737-6/7/8/900

I've come across a number of instances where the compressor for potable water tank pressurisation was found not working (seized because of overheating), after replacement it was observed that the fill & overflow valve was leaking & that was causing the compressor to run continuously, since potable tank never got pressurised enough to trigger the pressure switch which cuts off power supply to the compressor. So whenever compressor is observed to be not working always ensure the condition of fill & overflow valve, as a leaking valve can cause the compressor to fail again.

        2 - All toilet flush systems inop ? Check servicing ball valve.  737-6/7/8/900

Sometimes before departure it happens that all the toilet flush systems become inop. The reason for the snag was found to be because of improper servicing of the waste system. After servicing of waste system it must be ensured that the ball valve be closed properly else the drain valve proximity switch will sense door open and disconnects the ground to the control relay of Vacuum blower thereby making the flush systems inop. Update: Another similar tip: THERE IS A COMMON PROBLEM OF ALL THE LAVS NOT WORKING WHEN THE A/C IS ON GROUND & READY FOR DEPARTURE. THE FIRST STEP IS TO CHECK THE CB ON P 18 PANEL & ON P 91. IF THE CB ARE IN, THE DRAIN BALL VALVE MECHANISM INSIDE TOILET SERVICE PANEL MUST BE CHECKED FOR PROPER SEATING. IF IT IS SLIGHTLY OUT THE PROXIMITY SENSOR INSIDE WILL SENSE AN OPEN CIRCUIT & NONE OF THE LAV SUCTION WILL WORK.

        3 -  Fwd galley drain blockage. 737-6/7/8/900 

FWD R/H GALLEY LEAKS GRAY(DRAIN) WATER .
AFTER INVESTIGATION FOUND GALLEY HAS A DRAIN STRAINER(FILTER) FOR GRAY WATER ,THIS WAS PARTLY BLOCKED (BY COFFEE RESIDUE)CAUSING WATER TO FILL THE DRAIN LINE AND OVERFLOW OUT OF A SECOND DRAIN POINT (POTABLE WATER FILTER)UNDER THE GALLEY
THIS MAY BE A GOOD ITEM TO CHECK DURING A OR C CHECKS ON NG'S
LOCATION OF STRAINER: OUTBD SIDE OF GALLEY ACCES VIA WASTE COMPARTMENT. I ASSUME ALL THE GALLEYS MUST HAVE THIS STRAINER FITTED, thanks to GJ v Diessen.

        4 - No rinse water during toilet operation. 737-6/7/8/900

If the toilets work properly but do not rinse when flushed, it could be the rinse valve filter. This filter can be cleaned if you remove the valve. Get access to the rinse valve by removing the lavatory covers and remove the valve. When you remove the valve, only take the top two clamps off. If you loosen the bottom clamp slightly you can pull the valve out (the bottom clamp is quite difficult to put back on). When the valve is out, undo the bottom part (where the water enters the valve) and you will find a small flat filter which can be cleaned or replaced. When you re-install the valve, put a small amount of vaseline around the bottom of the valve so that the clamp can pass over it before re-tightening it.

Thanks to a welshman-abroad.

        5 - New dirty job man fixes all your toilet problems. 737-ALL

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