It seems that Jabsco has re-designed its el-cheapo head so that the pump locks in the down position, thereby preventing any of the nasty siphoning or back-flow that can potentially cause problems. It looks promising, and I'm thinking seriously of ordering one, so I'm wondering if anyone else has converted? WM sells a 'Valve Cover Assembly' that purports to convert an older pump to 'Twist-n-lock' operation (#9532789). Cheers, Bob s/y X SAIL R 8
New Jabsco 'Twist n' Lock' Head pump
- Thread starter BobW
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same as wet/dry switch?
Bob If you haven't done so already, you might check out their web site which should have a blow-up of the parts diagram as they do for the other models. I'd compare to see if this is just another permutation of the wet/dry switch.
Bob If you haven't done so already, you might check out their web site which should have a blow-up of the parts diagram as they do for the other models. I'd compare to see if this is just another permutation of the wet/dry switch.
Bob, I replaced my Jabsco compact head
with the Tee handle pump (dislike them) with a Raritan PHC which is a PHC head on a compact base with a shorter handle on the pump. I'd recommend it for your consideration as opposed to trying to improve the Jabsco.
with the Tee handle pump (dislike them) with a Raritan PHC which is a PHC head on a compact base with a shorter handle on the pump. I'd recommend it for your consideration as opposed to trying to improve the Jabsco.
Not the same as wet/dry lever
The wet/dry valve doesn't haven't anything to do with backflow, it only blocks or allows incoming flush water. I've just spent 20 minutes studying the exploded drawing of the pump, and I can't see any difference in this version and the previous one except for the cover on the top of the pump...the new one has a "catch" in it that grabs the handle when it's rotated and locks the piston rod down. But unless something is pushing back hard enough on the previous version to push the piston rod up, I can't figure out how locking it down would accomplish anything more than just leaving the piston rod in the down position...but maybe I'm missing something. They've taken the drawing of their previous version off their website, which makes it impossible to compare the drawing of the new one with the old one unless you have a hard copy of the old one. Ted meant to say that the PHC is a PH II pump on a compact base.
The wet/dry valve doesn't haven't anything to do with backflow, it only blocks or allows incoming flush water. I've just spent 20 minutes studying the exploded drawing of the pump, and I can't see any difference in this version and the previous one except for the cover on the top of the pump...the new one has a "catch" in it that grabs the handle when it's rotated and locks the piston rod down. But unless something is pushing back hard enough on the previous version to push the piston rod up, I can't figure out how locking it down would accomplish anything more than just leaving the piston rod in the down position...but maybe I'm missing something. They've taken the drawing of their previous version off their website, which makes it impossible to compare the drawing of the new one with the old one unless you have a hard copy of the old one. Ted meant to say that the PHC is a PH II pump on a compact base.
It locks the piston all the way down...
which will prevent any waste water from flowing back into the toilet, because the 'flapper valve' (#16 on the parts diagram, link below) will be held shut. That valve 'flaps' UP on the upward stroke of the piston, which sucks water from the bowl into the pump cylinder, while the 'joker valve' (#33) prevents waste from flowing back in from the discharge hose. So I can believe that when the pump piston IS locked down, it will prevent backflow of waste water, and with the wet/dry lever in the dry position, nothing's coming in from that end....... but I'm still not going to dispense with my vented loops because they ALWAYS work, but the lever and lock will ONLY work when they are set by the user. I think I'll buy the locking lever to get that extra bit of security...... BTW, I found a Jabsco pump cylinder on Defender (#500162) that comes with: pump cylinder (#28) top valve/gasket (#21) base valve/gasket (#16) discharge flange (#32) joker valve (#33) Discharge elbow (#34) All that for only $40.99.... it's everything you need to service the toilet except for the o-ring on the cylinder itself.... WM wants more than $60 for their service kit and you end up with a bunch of left-over parts. Cheers, Bob s/y X SAIL R 8
which will prevent any waste water from flowing back into the toilet, because the 'flapper valve' (#16 on the parts diagram, link below) will be held shut. That valve 'flaps' UP on the upward stroke of the piston, which sucks water from the bowl into the pump cylinder, while the 'joker valve' (#33) prevents waste from flowing back in from the discharge hose. So I can believe that when the pump piston IS locked down, it will prevent backflow of waste water, and with the wet/dry lever in the dry position, nothing's coming in from that end....... but I'm still not going to dispense with my vented loops because they ALWAYS work, but the lever and lock will ONLY work when they are set by the user. I think I'll buy the locking lever to get that extra bit of security...... BTW, I found a Jabsco pump cylinder on Defender (#500162) that comes with: pump cylinder (#28) top valve/gasket (#21) base valve/gasket (#16) discharge flange (#32) joker valve (#33) Discharge elbow (#34) All that for only $40.99.... it's everything you need to service the toilet except for the o-ring on the cylinder itself.... WM wants more than $60 for their service kit and you end up with a bunch of left-over parts. Cheers, Bob s/y X SAIL R 8
Could be interesting to see what happens when
Somebody keeps pumping and pumping the toilet against a blocked tank vent till the tank is REALLY pressurized--which people have been known to do... then locks down the piston. If nothing can escape via the bowl, something will have to give.
Somebody keeps pumping and pumping the toilet against a blocked tank vent till the tank is REALLY pressurized--which people have been known to do... then locks down the piston. If nothing can escape via the bowl, something will have to give.
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