Lavac Loo

[DownWest]

I am making some SS bits for a MoBo, owner came in yesterday and was muttering about his Lavac W.C. It is electric with a Jabsco diaphragm pump. Just fitted and bought off the bay as 'new'.

Talking him through it, it sounds like there is no non return valve on the entry of the pump. I am not familiar with the electric ones, just the manual with Henderson bilge pumps. But the pump can't work if there are not two NRVs?? He has looked and said he couldn't see one.
Any comments?
DW

 

[VicS]

I am making some SS bits for a MoBo, owner came in yesterday and was muttering about his Lavac W.C. It is electric with a Jabsco diaphragm pump. Just fitted and bought off the bay as 'new'.

Talking him through it, it sounds like there is no non return valve on the entry of the pump. I am not familiar with the electric ones, just the manual with Henderson bilge pumps. But the pump can't work if there are not two NRVs?? He has looked and said he couldn't see one.
Any comments?
DW

ITYWF older ones have a motorised version of the manual pump. http://www.blakes-lavac-taylors.co.uk/pdf/lavac.pdf

Later ones I think may have a Jabsco Macerator pump. ( or similar?) The pump itself has no valves. See http://www.jabscoshop.com/marine/pumps/toilet-waste-pumps/18590-2092-macerator-pump.htm but I imagine one would fit one to the outlet.

I agree with you though if it is a diaphragm pump it'll need inlet and outlet valves. One of these perhaps http://www.jabscoshop.com/marine/pu...f-priming-diaphragm-waste-pump-12-volt-dc.htm
There is no diagram of its parts but I notce that there are two joker valves in the service kit.

 

[howardclark]

I had to strip down and repair mine earlier this year - I have an electric pump and manual pump in line. My Jabsco pump has a blue cover. There are NRVs either side of the pump. I bought a repair kit which contained new NRVs and main seal.
HKC

 

[pvb]

Is that an avatar or a mural?

 

[DownWest]

Thanks guys, the system empties the bowl then pulses without any flush water making it in. Flush tubes are clear.

Me-thinks it was sold to him without a second valve.
DW

VicS, thanks for the links, I have forwarded them as he has no manual for the unit.

 

[rogerthebodger]

Just check that there is no calcium build up on the inlet flap valve.

On my Lavac some times calcium build up on the inlet valve stops it closing properly which results in the water in the pulsing in and out.

 

[VicS]

Thanks guys, the system empties the bowl then pulses without any flush water making it in. Flush tubes are clear.

Me-thinks it was sold to him without a second valve.
DW

VicS, thanks for the links, I have forwarded them as he has no manual for the unit.

The lid and seat must seal properly so that a vacuum is created in the bowl
Check that is is so.

The flushing water is then drawn in by the vacuum. The inlet seacock and hose must obviously be clear.
There should be a small pin hole in the inlet hose at the highest point in the loop to control this and ultimately break the vacuum, but this is explained in the manual

Assuming it is a diaphragm pump I doubt very much if it would pump at all without both suction and discharge valves .

A macerator pump will pump out OK but may not create enough vacuum to pull the flush water in .

 

[DownWest]

The lid and seat must seal properly so that a vacuum is created in the bowl
Check that is is so.

The flushing water is then drawn in by the vacuum. The inlet seacock and hose must obviously be clear.
There should be a small pin hole in the inlet hose at the highest point in the loop to control this and ultimately break the vacuum, but this is explained in the manual

Assuming it is a diaphragm pump I doubt very much if it would pump at all without both suction and discharge valves .

A macerator pump will pump out OK but may not create enough vacuum to pull the flush water in .

It is the round diaphragm pump and the system is just fitted, so no calcium or blockages, he checked. Now found the missing part on Jabsco's site and all will be resolved.
DW