Vacuflush Head Help

[Kizuna]

This is my third season with a Vacuflush Head on a 2005 Marlin. We use it lightly, and the first two years I only had to pump it out at the end of each season. This year I've already had to pump it out 3 times. Couple things I've noticed.

First I hear my water pump prime without water use every now and then. I haven't timed the intervals, it would be by chance if I'm in the cabin and hear it go. To me this would indicate a leak in the system. The bowl is dry, so it doesn't seem to be leaking at the flush point, but I'm wondering if fresh water is introduced somewhere else within the line. Is it possible my waste tank is slowly filling with fresh water when the system is not being used? Also, to the bowl being dry, it used to hold water until it was flushed, but now it seems the water seeps through the seal slowly draining. Don't think that's related, but noting it just in case.

Second thing I notice is the green discharge light goes on when the Head switch in the DC panel is turned on to use the system. The key is turned to the off position and removed. The holding tank discharge switch on the DC panel is off. I don't recall this light going on before, but I could be mistaken. LMK if this is normal or if the light shouldn't going on in this instance.

I'm looking to find someone locally that can help me trouble shoot the system and make sure it's working properly, but any knowledge and thoughts I can gain from here is greatly appreciated.

 

[efx]

You have a leak somewhere that is filling the holding tank. It probably fills the bowl just a bit but you can’t see it and then it goes to the holding tank. Seals / valve are probably failing. Is it raw water that goes to the head and then the holding tank? Did you Close the seacock or do you leave it open? The green light goes on went the float in the tank indicates it’s full or empty. I recall a green light on the groco panel as being empty.

 

[Kizuna]

You have a leak somewhere that is filling the holding tank. It probably fills the bowl just a bit but you can’t see it and then it goes to the holding tank. Seals / valve are probably failing. It’s it raw water that goes to the head and then the holding tank? Close the seacock or do you leave it open?

The system pulls from the fresh water tank. I'm now keeping my water pressure switch off and turning it on only when I need fresh water, to see if I get more time out of the system. It's a little bit of an inconvenience since I use the aft shower quite a bit when I'm fishing and like having the water ready to go, but to prove the theory that unasked water is filling the tank I can deal.

The only seacock related to the system is the overboard discharge valve. That's closed.

 

[seasick]

Does that boat flush with fresh water?

 

[wspitler]

You could have a slow leak in your fresh water system somewhere other than the head. But to confirm it's the head, try leaving a couple inches of water in the toilet and see if it drains over a short time. If it does, you can try to reseal it by turning everything off and cleaning the ball and seal in the bottom of the bowl by pushing the flush handle down and putting some silicon grease on both the ball and the flange. The vacuum tank pump should keep a vacuum on the tank and if the bowl seal is bad, the water will be sucked into the holding tank. The vacuum pump sounds different than the freshwater pump and it will cycle often if there is a vacuum leak anywhere in the system. The discharge pump is another sound and pumps thru the seacock, The green light you mentioned may be the tank level, if similar to mine. The green light on the level indicator is above the green light on the discharge panel. The discharge green light should only be on when the switch for discharge is on and the key is on. The shutoff for discharge is automatic and the discharge light should go out when the green tank empty light comes on. I had similar symptoms and had a freshwater leak under my cockpit sink, making the freshwater pump cycle.

 

[Kizuna]

Does that boat flush with fresh water?

Yes it flushes with fresh water.

 

[seasick]

I just looked that up and yes it does.

 

[seasick]

Look up your model bowl on the manufactures web site for FAQs and trouble shooting. I am not experienced with that fresh water system but it seems that if the breaker is ON, a pump pressurizes the water tank. Something has to stop water flow when pressurized but not being flushed' I suspect whatever that part is, it is leaking and water is slowing entering the bowl and also slowing draining to the holding tank.
This is an no so educated guess on my part

 

[Kizuna]

You could have a slow leak in your fresh water system somewhere other than the head. But to confirm it's the head, try leaving a couple inches of water in the toilet and see if it drains over a short time. If it does, you can try to reseal it by turning everything off and cleaning the ball and seal in the bottom of the bowl by pushing the flush handle down and putting some silicon grease on both the ball and the flange. The vacuum tank pump should keep a vacuum on the tank and if the bowl seal is bad, the water will be sucked into the holding tank. The vacuum pump sounds different than the freshwater pump and it will cycle often if there is a vacuum leak anywhere in the system. The discharge pump is another sound and pumps thru the seacock, The green light you mentioned may be the tank level, if similar to mine. The green light on the level indicator is above the green light on the discharge panel. The discharge green light should only be on when the switch for discharge is on and the key is on. The shutoff for discharge is automatic and the discharge light should go out when the green tank empty light comes on. I had similar symptoms and had a freshwater leak under my cockpit sink, making the freshwater pump cycle.

Thanks, wspitler. I will definitely try cleaning the ball and seal and adding silicone to the seal. I'm familiar to each of the sounds of the vacuum pump, water pump and discharge pump. Currently when I turn on the head switch in the panel I hear the vacuum pump running. I can also hear it sucking air through the ball and seal. If the system pressurizes, should the vacuum turn off like the water pump? Right now it doesn't, nor is it pressurizing with the constant pull of air and water.

The green light is NOT the tank level indicator. It's the one at the center-bottom of the panel. Also, when this green light is on, I'm not hearing the discharge pump run. Thanks for clarifying that this light should only be on with the key and switch, which are both off. Yet it goes on with the head switch turned on. I hear the discharge pump with key and switch on. Really curious on why this is, and powering up the vacuum is turning this light on. It used to be only the level indicator lights.

The symptoms of the freshwater pump cycling I've experienced as well. When I first got the boat the aft cockpit shower head was leaking. I replaced it and that led to causing a leak at the windshield washer due to new pressure in the system. Resolved that and then the cockpit sink started a leak. That has been resolved but now again I hear the pump prime every now and then.

 

[DennisG01]

The only way for fresh water to get into the black water holding tank is through the hole in the toilet bowl. You could tape paper towels to the inside of the toilet bowl to see if the flush water is leaking into the bowl and then past the seal. Even if the towels get wet, then dry, you will still be able to tell that they had gotten wet.

I shouldn't say the "only way"... the other possibility is a pump-out fitting where the o-ring is shot and allowing rain water in.

 

[DennisG01]

Yes, the vac pump should turn off once the system reaches the proper vacuum. It should not turn back on again. This is not your water problem, though. BUT, vac leaks can be the toilet bowl seal (as noted)... duck bills (common and a maintenance item)... vac switch... other seals at the tank... it could even be a small clog in the duckbill.

 

[Kizuna]

Thanks DennisG01. All great information. I'm going to try the paper towel test. The bowl "looks" dry, but it's not like I'm putting my hands in there to feel if it is . I'll also get some model numbers and order new duckbill seals and a toilet bowl seal. It's raining today and we're going to get a lot tonight, so I can mark the current level of the waste tank and see if it changes overnight with everything off. But my suspicion is I have a leaking water seal at the toilet + other leaks not allowing the vacuum to fully pressurize.

I'll start with these maintenance items and continue to diagnose from there, if need be.

 

[seasick]

I think the duck bill valve is also called a joker valve.

 

[wspitler]

Before you begin to do things like changing duck bill valves, make sure to run gallons of RV/Marine holding tank freshner/treatment through the entire system. Fill the entire holding tank with water via the bowl and pump it out. It allows you to check the level sensors as you fill and empty it. If you routinely use the marine or RV toilet treatment it helps lubricate the duck bill valves, keeps sensors clean, and sanitizes. Before I break my system, I flush it several times. The blue or green color of the chemical makes it easy to see leaks as well.

 

[Kizuna]

Ok, so the plot thickens. I ran to the marina to investigate some more and see if I can locate some part numbers etc. I turned the water pressure on and timed the water pump primes. 1st was at 50 seconds, then at 01:17 after the first, 01:30, 01:46, 01:53, 01:59, 02:02, 02:05 adding a little more time between cycles. Regardless, I put paper towels in the toilet and they remained completely dry all the while I was at the boat and hearing the water pump prime every couple of minutes. So I must have a leak somewhere else in the fresh water system.

wspitler, I always add holding tank treatment after I empty the tank, but I've never done just a full flush of the system with it. I can do it before any disassembling, as you mentioned leaks are easier to see.

One other thing I found on an old post is someone's vent was clogged and caused vacuum sealing problems. He had this problem after an overly full tank, which I had when the tank filled up on me the first time – way earlier than I was expecting based on previous seasons.

Attached are pictures of the discharge light on. If you look closely the discharge key is turned to off, and the switch on the panel is off. With access panels removed it's clear that the vacuum pump is running and the discharge pump isn't.

 

[wspitler]

With the head switch "on," one of the tank level lights should also be lit and it appears it is not. I'd try cycling the key with the discharge breaker on to see if it will free up the discharge pump relay. The light says the pump is on, but you confirmed it is not, but can you make it run via the key? I'd also try flushing the system to see if there are problems with the level sensors. There are several deutsch connectors that connect the control box (on top of the tank) to the pumps and sensors. Check them for corrosion and tightness. If both the pumps run and the vacuum pump pulls a vacuum, at least they are working. The vacuum tank should hold a vacuum for hours if the bowl seal is good and there are no other leaks. I have had freshwater system leaks at a cracked transom shower nozzle and under the cockpit bait station sink. Good luck!

 

[Kizuna]

With the head switch "on," one of the tank level lights should also be lit and it appears it is not. I'd try cycling the key with the discharge breaker on to see if it will free up the discharge pump relay. The light says the pump is on, but you confirmed it is not, but can you make it run via the key? I'd also try flushing the system to see if there are problems with the level sensors. There are several deutsch connectors that connect the control box (on top of the tank) to the pumps and sensors. Check them for corrosion and tightness. If both the pumps run and the vacuum pump pulls a vacuum, at least they are working. The vacuum tank should hold a vacuum for hours if the bowl seal is good and there are no other leaks. I have had freshwater system leaks at a cracked transom shower nozzle and under the cockpit bait station sink. Good luck!

I thought about turning on the discharge switch and cycling with the key, but I didn't/don't know if doing so with the discharge seacock closed would cause any damage to the system. If that's safe to do, I can try it with the seacock closed, but didn't want to risk it and I can't discharge at the dock, in the bay etc.

The majority of level sensors have never worked since I've had the boat or at least the lights seem very dim. Fortunately the full level light glows a bright red, so I know when it's full. I did see the sensors at the top of the tank and will look into that. My fresh water meter is also stuck at full, so I don't get that readout either

Thanks for all your input! Learning quite a bit about marine vacuflush systems on a rainy Sunday.

 

[wspitler]

I thought about turning on the discharge switch and cycling with the key, but I didn't/don't know if doing so with the discharge seacock closed would cause any damage to the system. If that's safe to do, I can try it with the seacock closed, but didn't want to risk it and I can't discharge at the dock, in the bay etc.

The majority of level sensors have never worked since I've had the boat or at least the lights seem very dim. Fortunately the full level light glows a bright red, so I know when it's full. I did see the sensors at the top of the tank and will look into that. My fresh water meter is also stuck at full, so I don't get that readout either

Thanks for all your input! Learning quite a bit about marine vacuflush systems on a rainy Sunday.

My freshwater gauge sticks sometimes, but tapping it often frees it up. I did have to change out the freshwater tank sensor. Pretty easy to replace that on the 330.

 

[seasick]

I am a bit confused as to what the problem is. The original post stated that the waste tank was filling up more often than expected. I don't see how a fresh leak would do that except when the bowl 'flushes' There is no direct connection between the fresh water tank and the holding tank.
When you the waste tank needed to be drained, was it actually full or did you just go by the indicator light? How was the holding tank emptied? Did you confirm that the tank was really full and was really empty after pump out?
It is in theory possible that for some really weird reason, bilge or sea water is filling the waste tank but I am not sure how the plumbing is routed. Is the overboard discharge seacock closed during normal boating?

 

[Kizuna]

Thanks seasick for your inquiry. I'm confused as well. Yes my OP stated that the tank is filling up more than expected, which it is. The first two seasons, I only emptied it once at the end. So I was surprised one day in early July, my daughter said the toilet won't flush. But sure enough the water was backed up to the head. At first I thought something was clogged, but the full light was also lit up. I use Pump Out which is a free service by our town that will come to your boat and empty your wast tank. I called them, and sure enough as they pumped, everything from the toilet on went away. Two or three more weeks go by, and my full light is on again. So Pump Out comes again and empties the tank. I asked the guy if around 10 gallons of waste was pumped incase my meter was faulty but he thought 10 gallons was a reasonable assessment. Two or three weeks go by and again the light is on, and I get it pumped out leading to my OP.

To know the tank has been emptied, we wait until nothing else is flowing, then I give a long flush and we wait until that last surge of liquid is gone. Sometimes a second time for good measure.

The overboard seacock has never been opened since I've owned the boat, since I always use the pump out service and prefer not to dump overboard even if I'm 5+ miles out.

Since the bowl seems to be remaining dry during my intermittent water pump priming there are two theories in play. The pump out guy mentioned there could be a calibration that is off and my system is using more water than needed when flushing. Not sure about that since it doesn't look like it has changed. Secondly as mentioned above, rain water and water washing the boat is getting through the waste pump out cap. It seems tight to me, but I need to inspect it more closely.

The vacuum sealing and discharge light are separate problems but all related to my head system.