I'm getting air into my water line. I've checked all my fittings and they are tight. What I suspect is that the problem lies inside the water tank. I can purge the air out of the system with a full fill and then after a short while, when I've drained off a few gallons, I get air entering. I think it is the pick up tub. Has anyone looked inside their water tank to see how the tube is attached to the fitting that then exits the tank and attaches to the water line heading to the pump? Is it worthwhile to repair the problem or cut a hole into the tank and attach a whole new fitting?
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Well, that's strange, for sure.
Here are two thiings I would check-
Is the tank vent clear? If the vent is not clear, you could be pulling air from a hose fitting instead of water out of the tank. As a test you could open the fill cap to the tank and see if you still have the problem. If no, then you have an issue with the vent. If yes, then the problem is elsewhere.
If you have two or more tanks connected to a manifold with a valve for each tank, are the other tanks shut off? Do the other valves close tightly? Maybe you are pulling air from another tank.
The tanks that I can see on my boat have the water outlet on the bottom of the tank. There is no way that I could pull air from the tank unless the vent were plugged.
Here are two thiings I would check-
Is the tank vent clear? If the vent is not clear, you could be pulling air from a hose fitting instead of water out of the tank. As a test you could open the fill cap to the tank and see if you still have the problem. If no, then you have an issue with the vent. If yes, then the problem is elsewhere.
If you have two or more tanks connected to a manifold with a valve for each tank, are the other tanks shut off? Do the other valves close tightly? Maybe you are pulling air from another tank.
The tanks that I can see on my boat have the water outlet on the bottom of the tank. There is no way that I could pull air from the tank unless the vent were plugged.
On my 42, we spent a long time trying to find out where the air was coming from...it was the manifold itself - the plastic t valves were allowing air to enter regardless of their positions...replaced them with a better valve and all is well..
dave
dave
Tim: Most tanks just have a fitting in the bottom of the tank that allows water to be sucked out of the tank (very basic). I am with Rich. It would make more sense that it is a vent problem. When you fill the tank air has entered the system. Consequently there is room for some water to be pumped out of the tank. If your tank vent is blocked you are only going to pump so much water before it stops again. Have you tried either removing the fill cap and see if the water will pump. Do you let the water flow out of the overflow when filling the tank. This will back flush the vent hose so you can be fairly sure that the vent is not blocked.
Tim, the post is for an early H33? Is that what you have? No 33 Cherubini I have seen has a manifold nor a pickup tube. There is one tank with the hose to the pump coming off the bottom. Has yours been modified?
water tank
Yep, its an 1981 H33. The tank is in the bow under the v-berth with a 90 degree elbow welded to the top of the tank on the aft side. It is original equipment. The only thing I can figure is to install an inspection port and see what is going on. Then the next step is pretty destructive if I need to refit a tank/bladder or whatever.
Yep, its an 1981 H33. The tank is in the bow under the v-berth with a 90 degree elbow welded to the top of the tank on the aft side. It is original equipment. The only thing I can figure is to install an inspection port and see what is going on. Then the next step is pretty destructive if I need to refit a tank/bladder or whatever.
Trust me on this!!!!
Your tank is aluminum. The dip tube going into the water is aluminum. It is about 28 years old. There has been all sorts of chemical activity going on in that tank for years. water is an incredible chemical. Your aluminum dip tube has pitted through, leaving pin holes along it's length. As soon as the water level drops to the first hole the pump sucks air and it's all over.
Drill a new hole next to the original dip tube connection. Connect a piece of pvc pipe to the hose to the pump. Drop the new dip tube into the tank. Your water system will now suck.
Sometime this summer or next your tank will start to leak tiny amounts of fresh water. The cause will be the same pin holing. You have a couple of choices here. You can listen to all the doom and gloom folks, tear out the V-berth and put in an off the shelf tank and loose about 30 gallons capacity. The alternative is to coat the inside of the existing tank. Think of the tank now as a support system for a liner system. I used a "sloshing compound" from KBS coatings. It seems to be a serious urethane of some sort. The solvents are very strong. The coating is a system. Clean, prep, etch, coat, wait a long time for the stink to recede. (www.kbs-coatings.com) I did mine four seasons ago and it's just fine. Talk to the fellows there. My water experts tell me that epoxy is just fine also. If using epoxy I would thicken it. Either use an epoxy that does not blush ot wash off the blush before filling with water.
I has been there!
Your tank is aluminum. The dip tube going into the water is aluminum. It is about 28 years old. There has been all sorts of chemical activity going on in that tank for years. water is an incredible chemical. Your aluminum dip tube has pitted through, leaving pin holes along it's length. As soon as the water level drops to the first hole the pump sucks air and it's all over.
Drill a new hole next to the original dip tube connection. Connect a piece of pvc pipe to the hose to the pump. Drop the new dip tube into the tank. Your water system will now suck.
Sometime this summer or next your tank will start to leak tiny amounts of fresh water. The cause will be the same pin holing. You have a couple of choices here. You can listen to all the doom and gloom folks, tear out the V-berth and put in an off the shelf tank and loose about 30 gallons capacity. The alternative is to coat the inside of the existing tank. Think of the tank now as a support system for a liner system. I used a "sloshing compound" from KBS coatings. It seems to be a serious urethane of some sort. The solvents are very strong. The coating is a system. Clean, prep, etch, coat, wait a long time for the stink to recede. (www.kbs-coatings.com) I did mine four seasons ago and it's just fine. Talk to the fellows there. My water experts tell me that epoxy is just fine also. If using epoxy I would thicken it. Either use an epoxy that does not blush ot wash off the blush before filling with water.
I has been there!
The question no one has asked:
What exactly is happening? When you turn on a faucet, does it spit and sputter? Or does water run just fine for a brief time, then quit altogether? Or something else?
So how 'bout describing for me exactly what IS happening...in as much detail as possible, at different times.
What exactly is happening? When you turn on a faucet, does it spit and sputter? Or does water run just fine for a brief time, then quit altogether? Or something else?
So how 'bout describing for me exactly what IS happening...in as much detail as possible, at different times.
Water tank
Sam described the situation pretty accurately. The system works fine as long as the tank is topped up. As soon as the water level drops, air gets into the system, sputters and stops drawing water.
Sam-did you cut an access port into the tank to do your coating job or how did you access? And with the PVC draw tube, how did you attach it? With a nut and washer on the inside or some other way?
Sam described the situation pretty accurately. The system works fine as long as the tank is topped up. As soon as the water level drops, air gets into the system, sputters and stops drawing water.
Sam-did you cut an access port into the tank to do your coating job or how did you access? And with the PVC draw tube, how did you attach it? With a nut and washer on the inside or some other way?
Sam's analysis only works if...
There's a pickup tube in the tank instead of a discharge fitting at the bottom of the tank. If your tank's discharge fitting IS at the bottom, the level in the tank is irrelevant till it drops below the top of the discharge fitting...'cuz that's the ONLY way air could get into the lines.
If the discharge fitting is on the top of the tank, with a pickup tube insidie it, then Sam's analysis works...maybe...
'Cuz if air were getting into your system, it wouldn't just sputter and stop...you'd continue to get water along with a lot of sputtering and spitting.
Before doing anything else, I'd check the tank vent thru-hull for a mud dauber nest...'cuz everything points to a blocked tank vent. 'Cuz everything works fine for a short while immeidately after filling the tank...until the limited amount of air in the tank is gone, then the water pump pulls a vacuum.
I could be worng, but IMO it makes a lot more sense to check the obvious AND the least expensive to fix before doing anything drastic.
There's a pickup tube in the tank instead of a discharge fitting at the bottom of the tank. If your tank's discharge fitting IS at the bottom, the level in the tank is irrelevant till it drops below the top of the discharge fitting...'cuz that's the ONLY way air could get into the lines.
If the discharge fitting is on the top of the tank, with a pickup tube insidie it, then Sam's analysis works...maybe...
'Cuz if air were getting into your system, it wouldn't just sputter and stop...you'd continue to get water along with a lot of sputtering and spitting.
Before doing anything else, I'd check the tank vent thru-hull for a mud dauber nest...'cuz everything points to a blocked tank vent. 'Cuz everything works fine for a short while immeidately after filling the tank...until the limited amount of air in the tank is gone, then the water pump pulls a vacuum.
I could be worng, but IMO it makes a lot more sense to check the obvious AND the least expensive to fix before doing anything drastic.
I have had an access port on the top of the aluminum tank for years. When it came time to coat the inside of the tank I opened it up from a 6" beckson to an 8" Beckson with a clear screw off top. Yes, there IS a baffle there running across the tank, but skillful weilding of a Super Sawzall made short work of that. As far as the new plastic dip tube: gravity. I just wacked a hole in the top surface of the tank, dropped in the tube, and slopped silicone around it. Held for a year or so. Don't care a whole lot. I think at some later point I used stainless wockwire or cable ties to bind the plastic tube to the remaining stub of the original dip tube. VERY professional. Well, if nothing else it doesn't bang around too much any more, but it does draw water! If you want to get realy slick with it you can use a "bulkhead fitting". I have one I got from McMaster Carr a while back. If I ever find the fitting at a time when I have the energy to install it I will.
You should have an access port on top of the tank for cleaning anyhow. Untill you open the top of your tank you would not believe what it looks like inside. I'll bet lunch you have pinholes.!
PS. Your symptoms point to pinholes, not mud daubers. If it was mud daubers you would be able to draw water after a waiting period which would let air into the tank. From what I understand once you loose prime it is gone till you add water which would get the level above the pinholes.
You should have an access port on top of the tank for cleaning anyhow. Untill you open the top of your tank you would not believe what it looks like inside. I'll bet lunch you have pinholes.!
PS. Your symptoms point to pinholes, not mud daubers. If it was mud daubers you would be able to draw water after a waiting period which would let air into the tank. From what I understand once you loose prime it is gone till you add water which would get the level above the pinholes.
water tank
The first thing I checked was for a vapor lock. I came to the conclusion that it had to be pitting and corrosion on the draw tube. I just did not know what to expect when I cut a hole in the tank and thought that I might have been able to screw a new tube in where the old one failed. A new hole and tube will get me by though.
The first thing I checked was for a vapor lock. I came to the conclusion that it had to be pitting and corrosion on the draw tube. I just did not know what to expect when I cut a hole in the tank and thought that I might have been able to screw a new tube in where the old one failed. A new hole and tube will get me by though.
H hh water tank access port, plastic dip tube.
Picture of top of water tank with 8" Beckson clear cap access port. Internal baffle can be seen inside, top of plastic dip tube just visable at bottom of picture. This should give you a better idea of what you'll find.
Picture of top of water tank with 8" Beckson clear cap access port. Internal baffle can be seen inside, top of plastic dip tube just visable at bottom of picture. This should give you a better idea of what you'll find.
Attachments
access plate
Sam--
Does the 8 inch port provide sufficient access? I was looking online and noticed a number or rectangular ones for a little more $. In retrospect, do you think you could have used a little more access? I'm an hour away from my boat so I am speculating that a 10x12 one could fit in.
Tim
Sam--
Does the 8 inch port provide sufficient access? I was looking online and noticed a number or rectangular ones for a little more $. In retrospect, do you think you could have used a little more access? I'm an hour away from my boat so I am speculating that a 10x12 one could fit in.
Tim
The 8" round port is just adequate. It allows me, with a bit of work, to accomplish what I have to inside the tank. I had considered using a rectangular hatch but felt there was too much chance of warpage causing a corner to lift, breaking the seal and allowing water to slop around. The round port's threads draw the cover evenly onto the annular seal (like that big word?) and maintain positive seal. I set the base in silicone but I'm sure someone will have a better idea for a bedding solution.
When I clean the tank I use a dedicated crevace tool on my shop vac to draw out the remains of liquid and a long handle commercial style toilet brush that allows me to scrub inmto all corners easily. I hardly ever mistakenly use it on the toilet. The coating I used (KBS Coatings) is a sloshing compound for fuel tanks and the like. As I couldn't roll the tank around to distribute the coating I used a "radiatior" paint brush which has a long handle with a crook at the brush end. I poured the coating in the tank per instructions and painted up the walls and cieling of the tank till the stuff set. BTW; I did my aluminum fuel tank with the stuff too but that tank is easy to get out so I was able to roll it to distribute the coating. I was also able to allow the fuel tank to sit in the full sun for a few days so full curing was quicker.
When I clean the tank I use a dedicated crevace tool on my shop vac to draw out the remains of liquid and a long handle commercial style toilet brush that allows me to scrub inmto all corners easily. I hardly ever mistakenly use it on the toilet. The coating I used (KBS Coatings) is a sloshing compound for fuel tanks and the like. As I couldn't roll the tank around to distribute the coating I used a "radiatior" paint brush which has a long handle with a crook at the brush end. I poured the coating in the tank per instructions and painted up the walls and cieling of the tank till the stuff set. BTW; I did my aluminum fuel tank with the stuff too but that tank is easy to get out so I was able to roll it to distribute the coating. I was also able to allow the fuel tank to sit in the full sun for a few days so full curing was quicker.
tank
I opened up the tank yesterday and it was as thought, a corroded draw tube. You were not kidding about the ecosystem living in that tank. I will give it a good cleaning and leave the coating until haul out. My immediate thought was that the diesle tank needs the same so I;ve added that to my list.
I opened up the tank yesterday and it was as thought, a corroded draw tube. You were not kidding about the ecosystem living in that tank. I will give it a good cleaning and leave the coating until haul out. My immediate thought was that the diesle tank needs the same so I;ve added that to my list.
Viktor;
If that question was aimed at me: There is no manifold on the Hunter 33 (C). I simply replaced the original aluminum dip tube with PVC plumbing pipe from Home Depot or Lowes. I could have used PEX or any similar plumbing system. The PVC was in stock in my garage so the price was right.
If that question was aimed at me: There is no manifold on the Hunter 33 (C). I simply replaced the original aluminum dip tube with PVC plumbing pipe from Home Depot or Lowes. I could have used PEX or any similar plumbing system. The PVC was in stock in my garage so the price was right.
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