If I run out of fresh water on my 1984 C-36, when I refill the tanks, the pump won't prime readily. I let the pump run for 15 minutes and nothing. If I loosen or remove the lines to the pump, this will usually get it going, though I don't know exactly why. Any ideas? Thanks, jv
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Rob R
Air Lock?
John, I'm wondering if, once the water is out of the tank, air is entering the line going to the pump, and un-priming it. When it is refilled quickly, is there any possibility that it is filling quick enough to lock the air into the pipe? A possible fix might be to make the exit hose from the water tank run slightly down hill on its run to the pump. Let us know how it goes... Rob
John, I'm wondering if, once the water is out of the tank, air is entering the line going to the pump, and un-priming it. When it is refilled quickly, is there any possibility that it is filling quick enough to lock the air into the pipe? A possible fix might be to make the exit hose from the water tank run slightly down hill on its run to the pump. Let us know how it goes... Rob
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andy
open all faucets
also there should be a check valve ( usually right after the pump) that might have some crud in it. or check all suction side hose fittings
also there should be a check valve ( usually right after the pump) that might have some crud in it. or check all suction side hose fittings
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Peggie Hall/Headmistress
That's normal...sort of
When you let the tank run dry enough that the pump starts sucking air, the plumbing also fills with air. It takes a while for the pump to reprime. I see your boat is an '84. The older the pump and the more worn the diaphragm, the longer it will take. If it's not repriming in under two minutes, it's sign that the pump is beginning to fail. If it's started cycling briefly for no reason, the diaphragm is definitely failing and should be replaced before it quits pumping water altogether--which ALWAYS happens at the least convenient time. Even when the pump is new, it's best not drain your water tank completely if you can avoid it. Repriming is hard work for the pump. Diaphragms CAN run dry without harm, but there's a limit to how much anything can take over time.
When you let the tank run dry enough that the pump starts sucking air, the plumbing also fills with air. It takes a while for the pump to reprime. I see your boat is an '84. The older the pump and the more worn the diaphragm, the longer it will take. If it's not repriming in under two minutes, it's sign that the pump is beginning to fail. If it's started cycling briefly for no reason, the diaphragm is definitely failing and should be replaced before it quits pumping water altogether--which ALWAYS happens at the least convenient time. Even when the pump is new, it's best not drain your water tank completely if you can avoid it. Repriming is hard work for the pump. Diaphragms CAN run dry without harm, but there's a limit to how much anything can take over time.
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Don Alexander
Check Valve??
John, Your pump is probably OK but there is a non return valve on the inlet and this is what retains the water pressure when the pump is off. i.e. after it has reached the switch off pressure set by the pump's internal switch. Now, if the feed line is dry and the head of water in the tank is insufficient to open the valve and admit water to the pump, you can run it all day and nothing will happen. The remedy is to get your mouth over an open faucet and SUCK - not very hard but just enough to unseat the valve. None of the other faucets should be on and the water will gush in less than a second. You need a flexible neck though! Never fails. Regards
John, Your pump is probably OK but there is a non return valve on the inlet and this is what retains the water pressure when the pump is off. i.e. after it has reached the switch off pressure set by the pump's internal switch. Now, if the feed line is dry and the head of water in the tank is insufficient to open the valve and admit water to the pump, you can run it all day and nothing will happen. The remedy is to get your mouth over an open faucet and SUCK - not very hard but just enough to unseat the valve. None of the other faucets should be on and the water will gush in less than a second. You need a flexible neck though! Never fails. Regards
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John Visser
Gee...
Don, I don't know if I want anyone to see me do that! I get your point, though. Is there something deficient about the check valve? And thanks also to others who replied. Peggy, I'll look at replacing the pump - I guess 18 years is a lot to be thankful for from such a pump. I shouldn't complain. I may also add an accumulator. Any specific recommendations? jv
Don, I don't know if I want anyone to see me do that! I get your point, though. Is there something deficient about the check valve? And thanks also to others who replied. Peggy, I'll look at replacing the pump - I guess 18 years is a lot to be thankful for from such a pump. I shouldn't complain. I may also add an accumulator. Any specific recommendations? jv
Look at the ITT Jabsoc Sensor VSD Pump.
John: You are going to rich once the National Inquirer gets the pictures of you doing your faucet. That being the case, you should look at the ITT Jabsco Sensor VSD pump. They cost about double the regular pumps, but may be worth it. http://tzar.nxtranet.com/prodInfo/overview/81000-346_ds.pdf
John: You are going to rich once the National Inquirer gets the pictures of you doing your faucet. That being the case, you should look at the ITT Jabsco Sensor VSD pump. They cost about double the regular pumps, but may be worth it. http://tzar.nxtranet.com/prodInfo/overview/81000-346_ds.pdf
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Bert
Exit Valve
JV, This happends to me all the time. The cure is fairly simple: Install a pump exit valve at the end of a couple of feet of hose, in the bildge, which is lower than the thank and the pump. Should you run out of water again, fill up the thank and then open the valve for a couple of seconds and the pump will re-prime. Fair winds.
JV, This happends to me all the time. The cure is fairly simple: Install a pump exit valve at the end of a couple of feet of hose, in the bildge, which is lower than the thank and the pump. Should you run out of water again, fill up the thank and then open the valve for a couple of seconds and the pump will re-prime. Fair winds.
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