My O'Day 28 has a problem with the water pressure. It only holds pressure when the tank is full. After the level drops a couple of gallons it looses pressure and won't bleed no matter how long I keep the pump running...faucets open or closed. This boat does have a hot water heater if that has any bearing on the situation. I don't really understand how the system works...how does it keep the pressure. I understand there might be such a thing as an accumulator in the system, or that the hot water heater/tank might work as an accumulator. I'd appreciate any information about how the system works so that I can try to figure out the solution to the problem. The pump is quite noisy. I'm not sure if this is normal or not. Right now I'm at the dock so I can fill the tank a couple of times a day. When icy winter sets in it will be hard to fill the tank very often as the supply lines will be frozen or underwater or both.
Water Pressure Problems
- Thread starter johnjensen
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This answer is from my weakening memory so here goes.
The water system on our IP38 had an accumulator tank (about 2 gallon size)that had a starting air pressure of say 10 pounds. The tank had an air bladder inside that held this pressure. When you turned the water faucet on the water pump filled the system with water that was now under pressure because the water filled that tank until the bladder would not compress any more There was a pressure switch that turned the pump on when the pressure dropped to a predertermed pressure and turned it off when it reached a higher pressure.
Look all over your water system and identify every part and then find the answer on this site from someone with better understanding. Like....Maine sail, where are you.
Good luck, Ray
The water system on our IP38 had an accumulator tank (about 2 gallon size)that had a starting air pressure of say 10 pounds. The tank had an air bladder inside that held this pressure. When you turned the water faucet on the water pump filled the system with water that was now under pressure because the water filled that tank until the bladder would not compress any more There was a pressure switch that turned the pump on when the pressure dropped to a predertermed pressure and turned it off when it reached a higher pressure.
Look all over your water system and identify every part and then find the answer on this site from someone with better understanding. Like....Maine sail, where are you.
Good luck, Ray
Thanks, Ray. I haven't tracked down every component of my system yet. You've given me at least some idea of how an accumulator tank works. My system does bleed and hold pressure when the tank is full...the pump comes on when I turn on the faucet and goes off again pretty soon after the water is shut off. The O'Day owner's manual has a diagram of the pressure system, but no reference is made to the accumulator. I wonder if it is in the main water tank. Thanks again for the information you gave.
We have an '85 Oday 28. It did not have an accumulator originally but we added one to fix problems with the pump short cycling often (like in the middle of the night). Also, if yours is like ours there is a check valve on the water heater intake, so it shouldn't be able to act as an accumulator. I agree with Ray that you should trace it all out to get an inventory of what you have before you can accurately troubleshoot. You might also have a shutoff valve on the water heater intake. You could try closing that and seeing what happens with only the cold water to cross the water heater off the list of possibilities. Off-hand I'd say it sounds like an issue with the internals of the pump but further investigation is in order.
Water Pressure Problem
The pump goes on when the faucet is open and goes off shortly after the faucet is closed. That is...until the water level drops by a few gallons, after which the pump runs continuously until it is shut off. The only way to get pressure back is to fill the tank again to overflowing.
Thanks for the reply
The pump goes on when the faucet is open and goes off shortly after the faucet is closed. That is...until the water level drops by a few gallons, after which the pump runs continuously until it is shut off. The only way to get pressure back is to fill the tank again to overflowing.
Thanks for the reply
Water Pressure Problem
Thanks Davidasailor;
Our system does do short cycles in the middle of the night also. I wonder where you got your accumulator. Thanks for the suggestion of shutting of the supply to the heater. That may give me some clues. I still don't understand how the system holds pressure if there isn't an accumulator. Perhaps some sort of valve in the intake pipes?
Thanks Davidasailor;
Our system does do short cycles in the middle of the night also. I wonder where you got your accumulator. Thanks for the suggestion of shutting of the supply to the heater. That may give me some clues. I still don't understand how the system holds pressure if there isn't an accumulator. Perhaps some sort of valve in the intake pipes?
We got the accumulator about 20 years ago. Probably from Defender Marine. Something like http://www.defender.com/product.jsp?path=-1|51|299222|121271|567586&id=121335 although I don't remember the exact size or make. We installed it under the bathroom sink directly to the output side of the pump.johnjensen said:
As for holding pressure, I'm unsure of the internals of the pump but there must be a valve in there that holds the pressure on the output side. There should also be a small filter on the input lines between the tank and pump that could be worth checking. As for noise levels, it's not unusual for it to be loud, that's why we didn't appreciate the late night cycling.
Also it just occurred to me to check that intake filter and any other joints on the intake side to make sure everything is tight, sealed, and no air can get pulled in. I vaguely remember having a nut vibrate itself loose off the filter allowing air in, preventing the system from priming well. That could be consistent with your symptoms if there is a leaky point in the plumbing below the high water level in your tank but above the slightly drained level.
Thanks for the link to the accumulator. I ordered one. Can't do anything but help, though it probably won't solve my problem. I guess I'll be pulling everything out of the lockers so I can track all of this down. Thanks again...
If you dont have an accumulator, and no obvious leaks, as a trial simply disconnect or manually bypass your hot water heater especially if its auxiliary heated from the engine fresh water supply. If the HW heater has developed a pin hole leak between the engines FW cooling loop and your pressure potable water supply, you may also notice that 'overflow tank' on your engine FW cooling circuit is routinely being 'filled' and discharging into the bilge. Hot water tanks dont last forever, especially if they're not electrically bonded to a galvanic isolator.
Why not put a extra control switch to the water pressure pump at the sinks and shower location. That's what I did.. only turn pump on when needed. Plus you can install dockside water preasure. Not that hard to do. Plus very quite at 3am...
A couple of things. The system should hold pressure with, or without an accumulator tank, but the tank just makes it cycle on and off less frequently. If you have a leak on the discharge side, water will leak out, lowering the pressure, and the pump will cycle on.
But the issue with the holding tank sounds like somehow, or someway, you are sucking air. If it gets enough air on the intake side, the pump will run continually, much like an injector pump shutting down, or a heart attack if air gets in your veins. Theoretically, it should hold pressure on the discharge side, preventing the pump from coming on indefinitely, without an accumulator.
One more thing, isolate the pump. Without it, those silly things cause a resonance in the hull that will wake the neighbors! It's easy enough to make with a couple of pieces of hose..
But the issue with the holding tank sounds like somehow, or someway, you are sucking air. If it gets enough air on the intake side, the pump will run continually, much like an injector pump shutting down, or a heart attack if air gets in your veins. Theoretically, it should hold pressure on the discharge side, preventing the pump from coming on indefinitely, without an accumulator.
One more thing, isolate the pump. Without it, those silly things cause a resonance in the hull that will wake the neighbors! It's easy enough to make with a couple of pieces of hose..
John, you have air entering the suction side of the pump .. A loose fitting above the water level as David noted is a possible.. Another thing to consider is the inlet at the tank. If there is a dip tube in the tank for the pump suction instead of a low point opening, the dip tube may have a leak or it may have broken at the level where you start seeing air. Be careful to turn off the electric side of the water heater when there is air in the system.. in fact don't turn it on until you've bled the hot water tank and system AFTER fixing the air entry leak.. You don't need an accumulator, they arre nice because they reduce pump cycling.. but on a system that does not leak on the pressure side, the pump normally does not run unless the water is turned on , which reduces the pressure below the pressure switch control point and turns on the power to the pump motor.. Air will not let the pressure build enough to turn the switch off.. Good luck on the hunt for the suction side air leak..
As I understand the situation, the pump operation appears to be normal when the tank is full, but continues to run when the tank level drops a few gallons. First, I would check to make sure the tank vent is clear of obstructions or water. If the vent is clogged/blocked, a vacuum could be formed in the tank and overcome the pumps suction as the water level falls. Second, I would look at the suction side of the pump. Air leaks on the suction side could keep the pump from providing sufficient suction as tank levels fall. Also, the water level of a full tank could provide sufficient pressure at the pump inlet (suction), that a bad or marginal pump could operate and provide normal pressure. As the tank level falls (decreased gravitational pressure) a marginal pump would be unable to provide sufficient suction on the inlet side and thus insufficient output keeping the pump running.
OK, John. One more thing to look at. Does your water tank have a vent? Do you hear a sucking sound when you open the tank to refill it? If yes, your vent is plugged and your pump is working against the tank suction. Otherwise, Kloudie is right. Your problem is between the fill nozzle and the pump suction. Although doubtful, you MAY have a clogged suction strainer. Doesn't sound like a clogged strainer. Sounds more like you're NOT getting air into the tank as the level falls or you ARE getting air into the suction line after the level has dropped a bit. The symptoms for both are similar. Your pump and the downstream system sounds good from your description of the problem.
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I agree, the problem is likely on the suction side of the pump. An accumulator tank will not fix this issue.
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