Galleymaid head pump Airbound

[JLR]

The VIP GM head pump has started to become airbound on the discharge side after every second or third flush. Releasing the priming plug on the discharge side releases the air and reprimes the pump and it discharges properly. The stator is relatively new ( less than one year or 30 flushes). I have a vented loop installed. Not too sure where to go from here but releasing the air after every second or third flush is not a good option. So, where is it sucking air from or what is the fix. I guess there is a possibility of something wrapped around the macerater but I do not think that would create this symptom. Also, I have not really cranked down on the small nuts that tighten the discharge bell to the housing so I guess I could be getting air in from there. After more than twenty years with GM heads on several boats, I would have thought I would have been able to fix this. Any help is appreciated.

 

[piripucha]

I had the same problem with mine, Razmarine has a troubleshuting list that may help you. In my case it was the small hose that goes from the water discharge into the head bowl and the plastic elbow . The small hose conector was full of deposit. i broke the seal with a wire and the problem went away. i hope this will help.

 

[ian w]

Have had this problem. The big hose going to the head has to RISE from the pump so that air goes away from the pump.

 

[JLR]

There is about a 12" rise from the pump to the back of the head.

 

[JLR]

I think the problem is fixed. The discharge hose from the bowl to the pump appeared to have a small hole in it -- enough to suck air on discharge. I am told it is fixed. Time will tell. Changed the discharge stator for good measure.

 

[questover]

I have the same problem on the master bedroom. Just got back from changing the stator on the galleymaid . Did not cure problem. Just talked to RAZ and going to do their checkout thing. But I have a feeling that will not fix the problem. Any thoughts why that vacuum break is on the master head and not on the other two heads? Which have worked fine for the last 10 years. This head has always been a problem. Boat is 58my 18'- 2" beam.

 

[JLR]

I actually added a vacuum break (vented loop) on my VIP head to make sure that it could never backfill above the waterline. In the course of fixing(I hope) the VIP head, the mechanic also cleaned the little duckbill on the vented loop. On my 56, the master head would be troublesome after cruising but eventually picked up the prime at dock. If you can get your head to work by loosening the priming plug on the discharge side, it is air bound. Check for any holes, no matter how small, in the discharge hose that could be permitting it to suck air when discharging. Also, as suggested by Razz, make sure you do not have a loose fitting on a small clear hose going from the bowl to the pump. I do not have that hose but some olde GM heads did. Keep us posted with the "poop".

 

[questover]

iNW. WOULD LIKE TO KNOW IF YOU RAISED THE 3'' INLET HOSE TO PUMP ABOVE THE BELL HOUSING AT THE PUMP? JLR IS RIGHT THAT THE STOOL ITSELF IS ABOUT 8-10'' ABOVE THE PUMP INLET. SO IF YOU RAISE THE 3'' HOSE ABOVE THE PUMP INLET HOW DOES THAT KEEP THE AIR LOCK AT THE BELL HOUSING FROM HAPPENING? RAZ MAINE SAID THAT THE PUMP IS ALWAYS DRAWING AIR FROM THE FLUSH. I'M WILLLNG TO TRY ANYTHING TO CURE THE PROBLEM. DID YOU ADD 3'' HOSE TO RAISE THE INPUT AT THE BELL HOUSING AND HOW HIGH (3-4'') ABOVE THE HOUSING? THANKS RUSS

 

[JLR]

Other than adding the vented loop on the discharge side, which goes above the water line, I did not change any of the plumbing. I did not raise anything.

 

[MikeP]

As I discovered a while back, GM states in their instructions that the heads need vented loops; Hatteras did not install them for whatever reason.

 

[questover]

I think i have figured out the cure for the problem gm head. I noticed that the bow and midship galleymaids push more water thru the flush cycle. So i believe the the master bed room gm head does not get ample water during flush. The lack of water then pulls air to pump. Pump then gets air locked. I'm going to run a dock hose to the gm and keep water high in bowl so no air can get to pump. If that works - then i'm going to replace stator @ intake and do away with the intake water high vent loop. This should help pull more water to the bowl. Also i have already put a checkvalve at the strainer to stop the siphoning while underway. The bow and midship gm's do not have vents and they sit @ or below sea water line. We will see?

 

[JLR]

Well- it's back. GM pump now will not discharge every second or third flush. So, like the studious owner I am, I read up on deposits in the discharge line. So, I added muriatic acid to the bowl today and sure enough, when I tried to flush, the roulette wheel landed on no flush. By the time the filling, bubbling etc had stopped, the bowl was full of muriatic acid, bubbles, baking soda bubbles and who knows what. Not happy to have to find a hand pump and a bucket to empty the bowl. So, as of now, the line from the bowl to pump still has dilted muriatic acid in it until tomorrow a.m. when my mechanic will swing by. Although I have had GM pumps for the better part of the last 16 years or so, I told my mechanic that I do not care what it takes to get the darn pump to flush reliably-- rip out what you need to, replace what you need to and let's finally get it fixed. Fortunately, he is more level headed than I and suggested that we see whether the acid did any good ( or damage) before we take any other steps. Sorry to sound frustrated but I have been working on this head issue for almost two years. I am convinced that the problem is between the bowl and the pump and that the pump is getting air bound. However, this time, I did not feel like standing on my head to loosen the discharge side priming pump to see if air and, of course, muriatic acid would rain down on me.

 

[skater]

I had the same problem and recently told Questover how to fix it. There is an extra plug on the top of the intake water pump and an extra plug on the top of the discharge pump. Remove the plugs and install 3/8 inch hose barbs and install a jumper hose between the 2 pumps . the toilet is too far from the pump and get airlocked. This will fix it. If there is not enough water in the toilet instsll a valve on the water pump end and you can adjust the amount of flow.

 

[ian w]

I have had and cured this problem.If an air bubble forms round the discharge stator it does not clear.The hose that goes to the head must rise from the pump to allow the air bubble to rise away from the pump.This can be achieved with a longer hose angling upwards or by making a base for the pump to have the hose to the head rising at the pump.My problem head was the central one on a 53 my

 

[MikeP]

The first thing to consider, IMO, when doing work on the head (or almost anything else, for that matter) is: WHY does the component/system need something modified NOW that it didn't need UNTIL now?

IOW, if it worked properly when new, it should work properly now in the same configuration. IF it doesn't then some part of the system is, as they say in the professional world, "broke."

Of course that could mean anything from plugged lines to worn out pumps, insufficient power, etc...

Installing valves/changing pump location or angle/adding bleed tubes, etc WASN'T necessary when all was fresh from the factory.

 

[davidwigler]

Make sure the seacock is fully open and the strainer is clean for maximum water flow and stop flushing before sucking air down the hole. Pause to let the bowl fill and flush again if needed. Works for me.

It's apparently normal to lose prime in the aft heads while running. The forward heads never do.

 

[MikeP]

Yes, our GMs will also lose prime when cruising. But while cruising, they will prime/fill/flush normally after a few seconds delay if I hold the flush button down. IOW, Upon initially pressing the button it will seem as if they have lost prime/won't work but after 3-4 seconds with the button down they re-prime and flush normally. This is the case at our routine cruise speed - 9-10 knots. I have not tried it on plane (as God..or Jack Hargrave, anyway... intended these boats to be operated) so I don't know how the heads will react at 17+ knots.

 

[JLR]

I appreciate all of the tips. First, the bowl is above the level of the pump. Therefore, the hose from the pump to the bowl does rise. Perhaps the angle of rise is not sufficient? Second, I am a little uncomfortable taking the priming plugs off of each side of the pump and replacing them with a hose. Is that what has been suggested? Third, I sort of agree with Mike. Why now? But, with that said, I need to eliminate the source of air getting in the discharge line. Raz seems to talk about some kit to insert a priming tube near the bowl. Not sure what that is about. Unfortunately, since this is a guest head, it is not feasible to expect guests to follow any special flushing instructions as to when to flush and when to stop. Pardon my ignorance with this question but is there something that can be screwed into the discharge line between the bowl and the pump (or at the priming plug on the discharge side) that would close when the pump is trying to discharge while still letting air out if any is in the line. Sort of like a flapper valve.

 

[skater]

The tech at Raz Marine told me to install the jumper hose to fix the problem. There are extra plugs on the intake and discharge pumps, use those.

 

[MikeP]

The original installation of the GM heads in the Hatts does not include a syphon break in the the intake and discharge line. At least, our boat does not have them and no other Oem Hatt/GM head installation I have seen has them. However, the instructions for the GM head installation/operation, which came with all the original paperwork for the boat DOES show that the heads should have them if installed in the configuration (re the waterline) that Hatt used.

I have no idea why Hatt installed the heads in a way that contradicts GM's instructions but, OTOH, they have worked properly in that configuration on our 53. But I think anti-syphons - as GM specifies - would eliminate issues with back-filling that seem to be mentioned regularly. Not sure it would have any positive effect on priming