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#1
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I woke up last night to the sound of the fresh water. I'd left the
switch on and it started in the middle of the night. The pump was running dry and the water tank was empty. There isn't a corresponding amount of water in the bilge and I couldn't find any sign of a leak so I'm trying to figure out where the water went. The pump has always cycled about every 10 minutes so I've been thinking there must be a small leak somewhere but I never could find it. We have the standard minimalist set up with a Jabsco PAR pump and pressure switch and no accumulator or tank. We have an Atlantic Marine hot water heater with the engine cooling water running through it. One possibility is that the heating coil in the tank corroded through and the water is leaking into the engine cooling system and down the exhaust. The big concern here would be filling up the muffler and then having water back up into the cylinder with the open exhaust valve. Has anyone heard of these heating coils developing leaks? Ours was a fresh water boat until last season so it doesn't seem likely but it's the only place I can think of the water going. I'll turn the engine by hand or check for a high water level in the muffler before starting the engine but I'd like to know if there is a precedent for a leak in the heater coil -- Roger Long |
#2
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I don't know about water tank leaks, but I did once have a leak in the
exit hose which was plastic instead of the appropriate metal leader. A few observations: The pump shouldn't cycle at all. Normally, ours is tight and never cycles, and the accumulator will even hold a bit of pressure after the pump has been off for a week. (I'm actually headed to the boat this morning to track down a leak suspected in the shower faucet.) An accumulator is a very nice addition and can be added anywhere in the system. You should have a few shutoff valves in the system. In particular, before the heater/hot water system is handy. Also, cockpit showers are a weak point and should be isolated. Roger Long wrote: I woke up last night to the sound of the fresh water. I'd left the switch on and it started in the middle of the night. The pump was running dry and the water tank was empty. There isn't a corresponding amount of water in the bilge and I couldn't find any sign of a leak so I'm trying to figure out where the water went. The pump has always cycled about every 10 minutes so I've been thinking there must be a small leak somewhere but I never could find it. We have the standard minimalist set up with a Jabsco PAR pump and pressure switch and no accumulator or tank. We have an Atlantic Marine hot water heater with the engine cooling water running through it. One possibility is that the heating coil in the tank corroded through and the water is leaking into the engine cooling system and down the exhaust. The big concern here would be filling up the muffler and then having water back up into the cylinder with the open exhaust valve. Has anyone heard of these heating coils developing leaks? Ours was a fresh water boat until last season so it doesn't seem likely but it's the only place I can think of the water going. I'll turn the engine by hand or check for a high water level in the muffler before starting the engine but I'd like to know if there is a precedent for a leak in the heater coil |
#3
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#4
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posted to rec.boats.cruising
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Roger Long wrote:
I woke up last night to the sound of the fresh water. I'd left the switch on and it started in the middle of the night. The pump was running dry and the water tank was empty. There isn't a corresponding amount of water in the bilge and I couldn't find any sign of a leak so I'm trying to figure out where the water went. I don't think your water tank is empty...I think the diaphragm in your water pump has failed. The pump has always cycled about every 10 minutes so I've been thinking there must be a small leak somewhere but I never could find it. As a diaphragm starts to fail, the pump will start to cycle for no reason (there is a reason: a drop in pressure caused by the leaking diaphragm)...at first just a brief "brrp" once or twice a day, then as the tear in the diaphragm gets bigger, more and more frequently and longer--and will take longer to prime when you first come aboard... till finally the pump runs continuously without pumping any water. I'll bet money that's what's happened. All you have to do to confirm it is check the water level in your tank. If your heat exchanger were leaking, you wouldn't have water in the engine, you'd have coolant in your water. -- Peggie ---------- Peggie Hall Specializing in marine sanitation since 1987 Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and Other Sources of Aggravation and Odor" http://shop.sailboatowners.com/books...ku=90&cat=1304 |
#5
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"Peggie Hall" wrote
I'll bet money that's what's happened. All you have to do to confirm it is check the water level in your tank. The tank was bone dry. If your heat exchanger were leaking, you wouldn't have water in the engine, you'd have coolant in your water. It's raw water cooled so all we would detect is the salt. -- Roger Long |
#6
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Roger Long wrote:
"Peggie Hall" wrote I'll bet money that's what's happened. All you have to do to confirm it is check the water level in your tank. The tank was bone dry. My money is still on the pump diaphragm. If you have a leak, the water has to be somewhere. You wouldn't be the first person to think there was more in the tank than you thought and ran it dry. You said you woke up the sound of the fresh water...did you mean the sound of water running somewhere? Or just the hammering of the water pump? If your heat exchanger were leaking, you wouldn't have water in the engine, you'd have coolant in your water. It's raw water cooled so all we would detect is the salt. Ok, SALT in your fresh water then. ![]() -- Peggie ---------- Peggie Hall Specializing in marine sanitation since 1987 Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and Other Sources of Aggravation and Odor" http://shop.sailboatowners.com/books...ku=90&cat=1304 |
#7
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refill you tank and use either a pool dye (best) or food coloring... I
bet you find the bilge water to have changed color. Then you just need to find the evaporated color stain and is should lead you to the leak. I would refill it once more and try it without the dye first... that will confirm if Peggy's theory is correct without staining your boat... Peggie Hall wrote: Roger Long wrote: "Peggie Hall" wrote I'll bet money that's what's happened. All you have to do to confirm it is check the water level in your tank. The tank was bone dry. My money is still on the pump diaphragm. If you have a leak, the water has to be somewhere. You wouldn't be the first person to think there was more in the tank than you thought and ran it dry. You said you woke up the sound of the fresh water...did you mean the sound of water running somewhere? Or just the hammering of the water pump? If your heat exchanger were leaking, you wouldn't have water in the engine, you'd have coolant in your water. It's raw water cooled so all we would detect is the salt. Ok, SALT in your fresh water then. ![]() |
#8
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I found the leak. Very small and didn't cause the problem on it's
own. It did however, cause the water tank to draw down faster than I expected. It must have been just on the verge of sucking air when I when I went to sleep. Now I know where that little wet trickle I thought was collected condensation was coming from. Next on my to do list, a way to check the fresh water tank level more easily. The pump is dry as a bone around the diaphragm, even after pumping enough to fill the holding tank 3/4 full with fresh water to flush it. The sink drain "T" into the head intake line works great although it means a lot of head pumping. The leak is in a metal to metal joint at the cold water inlet to the heater. The drip runs down the hose to a low spot so it isn't easy to spot. -- Roger Long |
#9
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Roger Long wrote:
I found the leak. Shot my theory in the tail. ![]() Very small and didn't cause the problem on it's own. Or did it...? Two problems, maybe? The pump is dry as a bone around the diaphragm... A failing/failed diaphragm wouldn't cause the pump to leak...it creates an air leak in the pump that causes the pressure to drop, which turns on the pump. As the tear in the diaphragm gets bigger, the pressure drops more often and lower, causing the pump to cycle more frequently and longer...till finally the pump can no longer prime. even after pumping enough to fill the holding tank 3/4 full with fresh water to flush it. ???...holding tank or water tank? The sink drain "T" into the head intake line works great although it means a lot of head pumping. Most likely because the toilet is pulling air through the sink that's preventing from priming. Put a plug in the sink when flushing with sea water...when flushing with water from the the sink, the sink needs to be at least half full. Just running water down the sink drain won't work 'cuz the toilet will pull more air than water. -- Peggie ---------- Peggie Hall Specializing in marine sanitation since 1987 Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and Other Sources of Aggravation and Odor" http://shop.sailboatowners.com/books...ku=90&cat=1304 |
#10
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![]() "Peggie Hall" wrote A failing/failed diaphragm wouldn't cause the pump to leak...it creates an air leak in the pump .... Ah, light dawns! It's harder to make things vacuum tight than pressure tight and much, much, harder than watertight. Developing porosity in the rubber would do exactly what you describe. The sink drain "T" into the head intake line works great although it means a lot of head pumping. Most likely because the toilet is pulling air through the sink that's preventing from priming. Put a plug in the sink when flushing with sea water...when flushing with water from the sink, the sink needs to be at least half full. Just running water down the sink drain won't work 'cuz the toilet will pull more air than water. No, it works perfectly in normal head mode. There is a valve in the line from the sink to the head intake line. What I meant by lots of head pumping was filling a 13 gallon holding tank by pumping the head. I really shouldn't have posted that point because it only applies to our very funky marina where there is no water hose bib within reach of the pump out station. I tried filling the holding tank by pumping fresh water through the system to avoid motoring back to the dock to fill with the hose through the deck pump out the way any normal person would. Now that I've done that once, motoring back and redocking doesn't seem like as much work as it did before ![]() -- Roger Long |
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