P42 forward electric head not working

[Spwiddy]

Hi all,

My forward electric head stopped working.

The switch has checked out ok and also the motor runs direct from a battery.
I am getting 12.8 v from the switch to the motor return, but when I press the switch the voltage drops to 0 v.

Has anyone else had a similar problem or can shed any light as to a solution.

Steve.

 

[Terry Cox]

Hi Steve, a puzzle for sure. Both of our original electric heads still work perfectly. My only suggestion would be to follow the circuit back to the source. If the motor runs when connected to a battery, and you have 12.8v at the switch, there must be a problem elsewhere. What happens when you bypass the switch, the motor runs, which means the switch is defective? Or...

When you press the flush button, that is supposed to close the anti-siphon solenoid/valve, which allows the motor pump to bring in sea water for flushing. It then opens when you stop flushing. That valve is located above and behind the shower bulkhead. The access panel to that valve is located in the most forward cabinet in the main salon starboard side. The small panel is held in place with screws. When you open the cabinet door, the panel is located on the forward side. Perhaps the valve is frozen thus preventing voltage from passing on to the toilet motor.

Would you please check that out and report back? Certainly an interesting problem.

 

[Spwiddy]

Hi Terry thanks for the reply,
Looking at the wiring I can see, it looks as though the anti-siphon valve is wired in parallel with the head motor so had discounted this as problem, but as I am a little lost as to the problem I am going to inspect it as suggested.
I will report back with my findings.

 

[Peggie Hall HeadMistress]

I am getting 12.8 v from the switch to the motor return, but when I press the switch the voltage drops to 0 v.

Always test the voltage to the toilet WHILE FLUSHING. What you get while it's just stting there is meaningless (as you've discovered). Your drops to 0, which means something in the wiring is preventing power from getting to the toilet when it's needed. That can be another piece of equipment on the same circuit (which, except for the solenoid valve, is a major no-no), a wiring fault...a failed solenoid valve...or a failing battery. So start by checking the voltage at the battery. If the battery is still strong, contact the toilet mfr tech support. At Jabsco, that would be Paul Campagna 978-282-5246 At Raritan you want to talk to Mac McCoy in their FL plant: 954-525-0378.

 

[Gene S]

Reading 12v from the motor return to the switch and then 0v as you hit the switch sounds normal. You need to read across the motor when you press the switch. Maybe they run 12v through the motor and ground it to run it. That is my understanding.

 

[Spwiddy]

Update

Thanks to all for the replies.

I run a cable direct from the battery, first from the negative with no improvement, then from the positive which allowed the head to work perfectly.
Then one breaker controls both heads feeding 2 independent positives (one to each head), so there must be a problem with the main feed wire going to the forward head, the aft head works fine.

The problem is I cannot find access to the main feed wire, it disappears under the shower then probably in an unaccesable duct under the starboard settee and then it appears behind the step panel by the nav station along with dozens of other wires.

Can any one point me towards a solution for replacing the wire?

Thanks, Steve.

 

[Peggie Hall HeadMistress]

This may be an off-the-wall suggestion..I've never thought of doing this to replace electric wire before.....but you MIGHT be able to do it the same way that often works to replace hoses. Put a new wire on the battery...splice the old one to the other end of it and pull it through as you pull the old one out from the toilet end. Or it might be better to do that in reverse...disconnect the old wire from the toilet and splice the end of the new one to it and pull it through to the battery.

 

[Terry Cox]

then it appears behind the step panel by the nav station along with dozens of other wires.

Hi Steve, Peggie has a good suggestion, but that bundle behind the step access panel will be a fish problem. You might be able to use that as your working point between there and the forward head. I've never had to deal with the head wires, so no help here.