I have a 1990 Hunter 30T which I purchased last year near the 1000 Islands and sailed home to Halifax, NS. During the trip the holding tank had been disconnected from the overboard discharge as per regulations in the Great Lakes. Now that I have the boat home and in NS, (where there are very few pump out stations) I have reconnected the overboard discharge but cannot get the hand pump to work. Is there a secret? I have dismantled and cleaned the pump but still cannot get it working. It is in good shape. In the discharge hose, at the highest point there is a valve of some kind....what is its function. There does not seem to be a way to prime the pump. Can anyone give me some tips to get this working. Thanks.
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Describe the valve or post a photo of it
Without knowing what it is, I can't tell you for certain whether it's the source of your problem...but I don't think it is. Have you tried to empty the tank at a pumpout? If not, your problem may be a blocked tank vent. The vents on all tanks--water, fuel, waste holding--have two essential functions: it allows air IN to replace contents as they are drawn out, and it allows air displaced by incoming water, fuel or waste to get out. Therefore, it's absolutely essential that all tank vents be kept open, because unless air can be pulled in through the vent to replace the waste (or anything else in ANY container) being pulled out, a vacuum is created in which nothing more can be removed--but in which strong suction from a pumpout CAN crack the tank. And a pressurized tank can have equally disastrous consequences--anything from a geyser when the deck fill or deck pumpout cap is removed to a backup in the toilet, to blown out fittings, to a cracked tank. So you don't want to use the toilet again till you're sure the vent is clear. The most likely places for a vent blockage are the thru-hull fitting and the inlet fitting on the tank. Before disconnecting the vent line from the tank to check, open the deck pumpout cap to relieve any pressure in the tank...'cuz if your tank is pressurized, it's gonna spew.
Without knowing what it is, I can't tell you for certain whether it's the source of your problem...but I don't think it is. Have you tried to empty the tank at a pumpout? If not, your problem may be a blocked tank vent. The vents on all tanks--water, fuel, waste holding--have two essential functions: it allows air IN to replace contents as they are drawn out, and it allows air displaced by incoming water, fuel or waste to get out. Therefore, it's absolutely essential that all tank vents be kept open, because unless air can be pulled in through the vent to replace the waste (or anything else in ANY container) being pulled out, a vacuum is created in which nothing more can be removed--but in which strong suction from a pumpout CAN crack the tank. And a pressurized tank can have equally disastrous consequences--anything from a geyser when the deck fill or deck pumpout cap is removed to a backup in the toilet, to blown out fittings, to a cracked tank. So you don't want to use the toilet again till you're sure the vent is clear. The most likely places for a vent blockage are the thru-hull fitting and the inlet fitting on the tank. Before disconnecting the vent line from the tank to check, open the deck pumpout cap to relieve any pressure in the tank...'cuz if your tank is pressurized, it's gonna spew.
Try the Valve
I cannot be sure without looking but the valve you may be refering to could be the switch that diverts the waste to either the holding tank or through the overboard discharge. If it has one hose approximately two inches in diameter that "y's" at the valve into two hoses and it is not in the proper position it will divert the waste into the holding tank instead of overboard. Give it a try.
I cannot be sure without looking but the valve you may be refering to could be the switch that diverts the waste to either the holding tank or through the overboard discharge. If it has one hose approximately two inches in diameter that "y's" at the valve into two hoses and it is not in the proper position it will divert the waste into the holding tank instead of overboard. Give it a try.
You may be onto something...
I assumed he was trying to dump the tank...and if the boat was on the Great Lakes, there isn't likely to be a y-valve in the tank pumpout line (at least there shouldn't be!). But if he's trying to flush the toilet directly overboard and can't make the toilet flush...??? Or...maybe he is trying to dump the tank, and that valve is indeed a y-valve in the pumpout line. So, Edward...just what ARE you trying to do? What pump is it that you can't get to work?
I assumed he was trying to dump the tank...and if the boat was on the Great Lakes, there isn't likely to be a y-valve in the tank pumpout line (at least there shouldn't be!). But if he's trying to flush the toilet directly overboard and can't make the toilet flush...??? Or...maybe he is trying to dump the tank, and that valve is indeed a y-valve in the pumpout line. So, Edward...just what ARE you trying to do? What pump is it that you can't get to work?
vented loop vent?
From Edward's description I assumed that he was talking about the vent at the top of the vented loop in the discharge line. My H37 (I just finished replacing all of my head hoses this weekend) has a plastic 180 degree bend/fitting with a vent at the top of it to prevent back-siphoning from the pump-out through hull. He did say that the "valve" was at the highest point. If this is the case, the vent (open or closed) shouldn't have an effect on the pump operation...but I believe that it should be closed off when you're actually pumping out the tank, and open at all other times to prevent siphoning.
From Edward's description I assumed that he was talking about the vent at the top of the vented loop in the discharge line. My H37 (I just finished replacing all of my head hoses this weekend) has a plastic 180 degree bend/fitting with a vent at the top of it to prevent back-siphoning from the pump-out through hull. He did say that the "valve" was at the highest point. If this is the case, the vent (open or closed) shouldn't have an effect on the pump operation...but I believe that it should be closed off when you're actually pumping out the tank, and open at all other times to prevent siphoning.
Air valve in vented loop should work passively...
However, a siphon break only affects water being PULLED through a line...that's how it break a siphon, by PULLING air into the line to interrupt the flow. But a siphon break has no effect whatever on anything being PUSHED through it, whether there's an air valve in the loop or not. So any vented loop installed after a pump cannot have any effect on whether the pump can push waste over it to the thru-hull...it could only cause a problem if it were installed ahead of the pump, 'cuz the pump is pulling from the tank, pushing out the thru-hull.
However, a siphon break only affects water being PULLED through a line...that's how it break a siphon, by PULLING air into the line to interrupt the flow. But a siphon break has no effect whatever on anything being PUSHED through it, whether there's an air valve in the loop or not. So any vented loop installed after a pump cannot have any effect on whether the pump can push waste over it to the thru-hull...it could only cause a problem if it were installed ahead of the pump, 'cuz the pump is pulling from the tank, pushing out the thru-hull.
Pump out problem
Thanks for all the responses. Just to update....I am trying to empty the holding tank using the hand pump to discharge overboard. There is no "y" valve on this boat. The line goes directly from the marine head to the holding tank. The holding tank can be pumped out thru the deck at a pump out station or if I open a thru hull valve and use the hand pump, it should go through the thru hull overboard directly under the boat. I have used pump out stations in the Great Lakes and all the way home to Halifax, but there are few pump out stations in NS so I wanted the manual overboard pump to work. I think that Ken is right, the valve I mentioned is on a 180 degree fitting and it would be perfect to ensure that sea water is not siphoned back to the tank after discharging. I believe my problem is in the hand pump, in that it is not self priming....even though it is supposed to be. I have dismantled it (that was fun) and am trying to find a re build kit for it, or will have to buy a different pump. Thanks for all your help.
Thanks for all the responses. Just to update....I am trying to empty the holding tank using the hand pump to discharge overboard. There is no "y" valve on this boat. The line goes directly from the marine head to the holding tank. The holding tank can be pumped out thru the deck at a pump out station or if I open a thru hull valve and use the hand pump, it should go through the thru hull overboard directly under the boat. I have used pump out stations in the Great Lakes and all the way home to Halifax, but there are few pump out stations in NS so I wanted the manual overboard pump to work. I think that Ken is right, the valve I mentioned is on a 180 degree fitting and it would be perfect to ensure that sea water is not siphoned back to the tank after discharging. I believe my problem is in the hand pump, in that it is not self priming....even though it is supposed to be. I have dismantled it (that was fun) and am trying to find a re build kit for it, or will have to buy a different pump. Thanks for all your help.
Wait a sec, Edward...
" the valve I mentioned is on a 180 degree fitting..." That definitely sounds like a vented loop...but that valve wouldn't have any impact on whether anything can be pumped over the loop. You said, "The holding tank can be pumped out thru the deck at a pump out station or if I open a thru hull valve and use the hand pump, it should go through the thru hull overboard directly under the boat." Assuming that you're smart enough to know whether the seacock is open on that thru-hull...what's in the tank discharge line--a y-valve or just a tee fitting? It also occurs to me that the PO might have put a plug in the thru-hull to satisfy the local law enforcment in his part of the Great Lakes. Or if the seacock handle may not be opening/closing the seacock any more. If the pump really is the problem, it's 15 years old...you might want consider just replacing it instead of rebuilding it.
" the valve I mentioned is on a 180 degree fitting..." That definitely sounds like a vented loop...but that valve wouldn't have any impact on whether anything can be pumped over the loop. You said, "The holding tank can be pumped out thru the deck at a pump out station or if I open a thru hull valve and use the hand pump, it should go through the thru hull overboard directly under the boat." Assuming that you're smart enough to know whether the seacock is open on that thru-hull...what's in the tank discharge line--a y-valve or just a tee fitting? It also occurs to me that the PO might have put a plug in the thru-hull to satisfy the local law enforcment in his part of the Great Lakes. Or if the seacock handle may not be opening/closing the seacock any more. If the pump really is the problem, it's 15 years old...you might want consider just replacing it instead of rebuilding it.
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