Vented Loop Use

[GonzoF1]

I am closing in on the install of an anchor washdown rig. When we were in the yard last month, we had them install a new thru-hull (3/4") dedicated to the task. As I put the plan to paper, I am wondering if I need to run it (raw water) thru a vented loop prior to the pump's intake side?

And while I am at it, I noticed the air conditioner system is not looped above the waterline either. Should I consider making that change as well?

 

[kloudie1]

The loops are used to prevent siphoning back into the hull or the engine where the water can do significant damage. On the AC system, the seas water side is fully closed to the inside of the boat so unless you have a condensate eductor, no loop is needed. On the anchor wash, a valve at the thru-hull would be mandatory, but no loop unless you'll have an open hose end below waterline level (and if ya plan on leaving the thru-hull valve open )

 

[GonzoF1]

The loops are used to prevent siphoning back into the hull or the engine where the water can do significant damage. On the AC system, the seas water side is fully closed to the inside of the boat so unless you have a condensate eductor, no loop is needed. On the anchor wash, a valve at the thru-hull would be mandatory, but no loop unless you'll have an open hose end below waterline level (and if ya plan on leaving the thru-hull valve open )

Thanks for the reply. Actually, I was thinking I would leave the valve open most of the time, but maybe not now. I suppose that since anchoring out and the need for the washdown system could be weeks apart, it would be smart to leave it closed. I guess the pump might lose prime and have problems at startup when it has to pull water over the loop.

Okay then... No loops. Thanks again!

 

[Graycruiser]

The loops are used to prevent siphoning back into the hull or the engine where the water can do significant damage. On the AC system, the seas water side is fully closed to the inside of the boat so unless you have a condensate eductor, no loop is needed. On the anchor wash, a valve at the thru-hull would be mandatory, but no loop unless you'll have an open hose end below waterline level (and if ya plan on leaving the thru-hull valve open )

We do have a "condensate eductor" on our AC, and it has a check valve in the line. Why would we need a vented loop here? Wouldn't the chance of a faulty check valve be as likely as the failure of the duck valve in the loop?

 

[Dan_Y]

Graycruiser
What model of eductor are you using? I'm looking for one that is trustworthy (not a waterbed eductor pump).
TIA,
Dan

 

[woodster]

the pump will not pull water if the loop is between the through hull fitting and the suck side of the pump it has to be on the discharge side of the pump to work

 

[Graycruiser]

Graycruiser
What model of eductor are you using? I'm looking for one that is trustworthy (not a waterbed eductor pump).
TIA,
Dan

It is the CR330 from Marvair® Division of AIRXCEL®, Inc www.marvair.com
From user manual...
The Marvair CR330 removes the condensate water produced during the cooling cycle of your
air conditioner and discharges the condensate into the air conditioner’s
outlet water line. The condensate is pumped overboard any time the air conditioner’s
circulation pump is working and sufficient condensate is in the condensate pan of your
unit. By operating on the Venturi effect, a separate condensate pump is not required.
A water filter/strainer, a reducer and a check valve are also provided and must be installed with
the CR330. The filter prevents debris from entering the CR330 and obstructing the water flow.
The check valve allows the condensate to flow in only one direction.

We bought it through our A/C supplier. Tain't cheap, but seems to do the job well leaving little to no water in the pan. The only maintenance seems to be cleaning the filter bow, screen, and blow-out the check valve before Winter layup. Instructions are good, and installation is easy. There are plenty of parts to accommodate different installations. A couple others in our marina also installed the CR330 with no complaints. It's been about 3-4 years since installation.