Groco HF not bringing water into the bowl

[Gusc]

Hi guys, I just took possession of my first boat - 1987 C34. I am totally new at this and within the first couple of hours I have my first project: the Groco HF toilet flushes ok if I pour water into the bowl and pump it (dry flush setting), but in wet flush, pumping does not bring water into the bowl.

What could be some root causes? Would the replacement kits fix this issue?

Thank you!

[Stu Jackson]

Welcome and congratulations.

A number of things enter into answers for you.

1.  Many "rebuild" kits have things you need and lots of parts you don't.  How to assess this is to learn about how a marine head works before you go any further.  The very best way to learn about this is to buy Peggie Hall's book:  https://shop.sailboatowners.com/prod.php?53615

2.  Another way to learn is to go to the 101 Topics sticky post on this forum and scroll down to Peggie Hall's Top Ten Hits.  https://c34.org/bbs/index.php/topic,6437.0.html

3.  The Groco is the lowest on the totem poll of all manual heads ever built.  As you are learning about heads, you should also, from your reading, learn what OPTIONS you have for replacement, which range from much better marine manual heads (Raritan - hands down) or electric (ease of use; higher complexity of installation).

4.  If you keep looking for sales, you may find that the replacement cost of the entire until is more cost effective than trying to rebuild your old one.

All the best.

[scgunner]

The seacock could be closed, otherwise the pump probably needs a rebuild, it's probably not pulling enough of a vacuum to pull the water into the bowl. When you pour water into the bowl it works because you're essentially priming the pump.

[KWKloeber]

@gusc

I have a Groco on my 84 C30.  It's the original. The only thing I've needed to do is replace the pump unit once and I think replace the joker once or twice. I doing Groco had excellent customer service and suggest you make a phone call. Ask for Patrick or Alby - (hope they're still there!)

I am clueless how the C34 is plumbed, but my sink and head are common to the same thru hull and there's a situation where the head will draw thru the sink drain (i.e. suck air) instead of seawater thru the sea cock. If yours is plumbed that way I can elaborate, if not forget the above. 

Note that Groco recommended that I go with a new pump rather than a kit because that's warranted and parts alone/my workmanship obviously are not.  If you replace I strongly recommend going the route. MUCH easier, no muss, no fuss, no runs, no drops, no errors - and you'll start w/ a new baseline on a new to you boat.

Hint: replace the slotted-head bolts holding the pump to stainless Allen head bolts.  Much easier to manipulate!!

[Gusc]

Thank you so much for the great insights!!

[Stu Jackson]

Gus,

Some of us have modified the OEM head inlet connections.  I did this, but never get any air pulling through the sink.

Head Odors 101.1 - "T" into sink drain:  http://c34.org/bbs/index.php/topic,5755.msg38216.html#msg38216

[KWKloeber]

Stu

Does the head intake hose make a straight shot to the head or there a considerable length from the thru hull?

My c30 intake had a long loop (That's the lower hose in the pic, the upper off the tee is the sink drain.)   I thought that was goofy so I shortened the hose so it went directly to the tee.

BUT then I sucked wind!  APPARENTLY between what seawater was in the shortened hose and the sink drain, there was barely enough for a one-stroke, BUT the thru hull didn't fill them quickly enough for a second stroke and so then pulled air. 
Going back to the long loop (so there was a "reserve" volume) returned to normal ops.

Another thing I love about the common drain is that monthly it's easy to drop a tablespoon of mineral oil (or baby oil to be sweet-smelling) down the drain to keep the pump working well for 20 years.

[Stu Jackson]

Stu

Does the head intake hose make a straight shot to the head or there a considerable length from the thru hull?

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Neither it's a "medium" length. 

The point is that on our boats the head sink is considerably higher than both the head and the waterline, so the sink drain hose is filled with water halfway up.  On my boat, the strainer is tight to the thru hull valve and the T connection is right above it, in those photos.

The 101 topics have my linked post about the T fitting change we made with pictures.

The head replacement project I did shows how far away it is:

PHII Installation with Photos  http://c34.org/bbs/index.php/topic,3797.msg45617.html#msg45617

[scgunner]

Gusc,

Before I started messing around with the plumbing I'd make sure the toilet itself was functioning properly. You did a dry flush test with water in the bowl, but did you do a wet test? With water in the bowl and on the wet flush setting, if the toilet is working properly, you should be able to pull seawater into the bowl and the pump should hold that prime. Also when you pump the bowl dry it should start refilling until you flip the lever to dry.

[Gusc]

Gusc,

Before I started messing around with the plumbing I'd make sure the toilet itself was functioning properly. You did a dry flush test with water in the bowl, but did you do a wet test? With water in the bowl and on the wet flush setting, if the toilet is working properly, you should be able to pull seawater into the bowl and the pump should hold that prime. Also when you pump the bowl dry it should start refilling until you flip the lever to dry.

Yes, I tested with the setting on 'wet' and manually filling the bowl with water. The water gets flushed but no additional water is brought in.

[Gusc]

Gus,

Some of us have modified the OEM head inlet connections.  I did this, but never get any air pulling through the sink.

Head Odors 101.1 - "T" into sink drain:  http://c34.org/bbs/index.php/topic,5755.msg38216.html#msg38216

Stu, thank you for your suggestion. Honestly, I am too new to be able to understand the modification. :) Next time I am at the boat I will take detail pictures and draw where the connections are going and coming. I am in the process of getting ready for a a 4-day sail to bring my boat to my home port, which should happen within the next 1-2 weeks. Until then I am about 3 hours away from it.

I am reading the book you suggested, which has been helpful to understand the system.

Thank you!

[Stu Jackson]

Stu, thank you for your suggestion. Honestly, I am too new to be able to understand the modification. :) Next time I am at the boat I will take detail pictures and draw where the connections are going and coming.
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You're welcome.

Between now and when you leave for your trip, perhaps you could look at the manual, which under the plumbing sections shows exactly how the OEM was connected.  Then you'll be able to better understand this slight mod.

Safe journey on your trip.

[Gusc]

You're welcome.

Between now and when you leave for your trip, perhaps you could look at the manual, which under the plumbing sections shows exactly how the OEM was connected.  Then you'll be able to better understand this slight mod.

Safe journey on your trip.

Hey Stu, sometimes I forget the most basic places to get information! I forgot to read the manual! Hahaha Thanks for the reminder.

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