I rebuilt my jabsco macerator last year and replaced the corroded brass bolts with ss bolts. also replaced all other parts using service kit (including gaskets) within a year, the macerator started leaking at the gasket seal. after disassembly and inspection, the only thing that appears to be wrong are premature wear of gaskets... while living vicariously and watching YouTubers rebuild their macerators... one guy was also installing a shutoff valve between the macerator input and the holding tank output. his thinking was that pressure from a pumpout station was sucking through the holding tank output through the macerator input then output and eventually to a closed through hull. he speculated that the pressure from the pump out vacuum had blown his macerator gaskets. since this rebuild is an undesirable chore and I'm starting the second one in just 1 year... it leaves me wondering if I should install a shut off valve between the tank and the macerator to protect it from damage / gasket blow out.... I would have thought that my unblocked vent would protect my systems from the pressure... thoughts? if you do recommend a shit of valve for the above reason... whatnpsindiesnit need to be rated for to survive the suction from a pump out vacuum?
holding tank pump out blowing macerator gaskets?
- Thread starter Ed whatnot
- Start date
the line to the macerator is a direct dedicated hose from the tank. it is not connected to the pump out hose. the pump out port is also its own dedicated hose.
In that case, a shutoff valve in it as close to the tank as possible may be the only solution, cuz you have to make it impossible for the pumpout to pull anything through the macerator plumbing. You may even be able to replace the hose fitting with one that has a shutoff valve.
---Peggie
---Peggie
thx Peggy. I'm just a little surprised that the vent wouldn't compensate for this and prevent pressure from going through the macerator... is this a common problem / best practice for plumbing heads?
how is this not a concern for pressure going through the tank and into the toilet / hand pump itself and blowing any of those seals...
I guess I'm just not 100 percent convinced thst it's pumpout pressure that blew my gaskets.
thx again for your insight.
how is this not a concern for pressure going through the tank and into the toilet / hand pump itself and blowing any of those seals...
I guess I'm just not 100 percent convinced thst it's pumpout pressure that blew my gaskets.
thx again for your insight.
Nothing is creating pressure, it's all suction. The pumpout is pulling in air via the vent. There's nothing preventing it from trying to pull it in anywhere else that's available...your macerator pump plumbing happens to be available, so it's pulling in water via an open thru-hull...which should always be closed when not actually in use to dump the tank. Keeping that thru-hull closed may eliminate the need for a shutoff valve.
--Peggie
sorry.. my use of pressure was confusing. I guess I consider it negative pressure (vacuum). the through hull evacuation port attached to the macerator is always closed for pump out. only open while using macerator. so no seawater gets sucked into macerator...so it's a dead end pipe. the original youtube video I watched where a guy was rebuilding his macerator was where I got the notion thst a shut off valve at the tank could be a good idea or could be allowing the vacuum pressure to blow the seals on my macerator... but given the thru hull remains closed at pump out... I expected the clean and clear vent would be the path of least resistance for the vacuum pressure from the pumpout.... either way I'll consider that shutoff valve as a failsafe. thx for your insight
My pump-out port is tee'd with the macerator , and I have never had this problem. And I have rebuilt my macerator several times and have never had the gaskets leak. I think your gasket issue is something else. But, FWIW, I always keep my over-board seacock closed when not actually pumping.
it sounded suspect to me as the cause but I had no other explanation so I thought it's worth asking here. in my case the macerator is not even teed. it's a direct /dedicayed line to the tank - as is the pumpout port.
like you, I keep my overboard seacock closed unless i'm macerating.
all that said I'm considering installing a shut off valve between tank and macerator.... even if its u likley to be the problem.... anything I can do to avoid yet another rebuild is time well spent.
here is the video that introduced the idea to me if you are interested.
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like you, I keep my overboard seacock closed unless i'm macerating.
all that said I'm considering installing a shut off valve between tank and macerator.... even if its u likley to be the problem.... anything I can do to avoid yet another rebuild is time well spent.
here is the video that introduced the idea to me if you are interested.