Cruisers Forum
 


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 16-10-2020, 16:48   #1
Registered User

Join Date: Jan 2015
Location: Seattle, WA
Boat: 1980 Pacific International Marine 41.5
Posts: 632
Where to position vented loop, exhaust or intake side

Trying to determine where the "proper" location of a vented loop should be, or if position doesnt matter.

My current setup has the vented loop between the water pump">raw water pump and the heat exchanger, however, the diagrams I am seeing online indicate that the vented loop should be located after the heat exchanger, before injecting into the mixing elbow.

Whats the proper position?
chowdan is offline   Reply With Quote
Old 16-10-2020, 16:54   #2
Registered User
 
Reefmagnet's Avatar

Join Date: May 2008
Location: puɐןsuǝǝnb 'ʎɐʞɔɐɯ
Boat: Nantucket Island 33
Posts: 4,501
Re: Where to position vented loop, exhaust or intake side

I'd go between heat exchanger and mixing elbow because it means less water can drain into the waterlock with engine off.
Reefmagnet is offline   Reply With Quote
Old 16-10-2020, 16:57   #3
Registered User
 
Dsanduril's Avatar

Join Date: Aug 2011
Location: Petersburg, AK
Boat: Outremer 50S
Posts: 4,024
Re: Where to position vented loop, exhaust or intake side

The closer the vented loop is to the exhaust/mixing elbow the less water there will be that falls down into the mixing elbow when the vent breaks a siphon. This, in turn, means there's less water that has a chance to make its way back up the exhaust system while the engine is off and potentially cause a lot of grief. If you have a fair sized water muffler or similar in the exhaust then the the volume difference is probably pretty negligible in comparison.

Bottom line, preferred is after the HX (for the reasons stated) but before the HX can work just fine. On some engines the connection from HX to elbow is so tight/special that trying to insert a vented loop there is somewhere between an exercise in frustration and impossible.
Dsanduril is online now   Reply With Quote
Old 16-10-2020, 17:13   #4
Registered User

Join Date: Jan 2015
Location: Seattle, WA
Boat: 1980 Pacific International Marine 41.5
Posts: 632
Re: Where to position vented loop, exhaust or intake side

Thanks guys. I just put an order in for a new piece to run from the RW to heat exchanger(Yanmar OEM part). Another $40 is a drop in the bucket when it comes to all new hoses.

I'll go with adding the vented loop between heat exchanger and mixing elbow. Reducing the amount of water that can enter the muffler is ideal as I've got a fairly long run - about 7.5 feet from lift can to loop before exiting so having the least amount of water in this area is ideal.
chowdan is offline   Reply With Quote
Old 16-10-2020, 20:02   #5
Senior Cruiser
 
DeValency's Avatar

Cruisers Forum Supporter

Join Date: Oct 2018
Location: Boston
Boat: Farr 40 (Racing), Contest 43 (Cruising)
Posts: 732
Re: Where to position vented loop, exhaust or intake side

Quote:
Originally Posted by chowdan View Post
Trying to determine where the "proper" location of a vented loop should be, or if position doesnt matter.

My current setup has the vented loop between the raw water pump and the heat exchanger, however, the diagrams I am seeing online indicate that the vented loop should be located after the heat exchanger, before injecting into the mixing elbow.

Whats the proper position?
The later is the correct way to go. You don't want sea water reversing into the elbow and heat exchanger
__________________
New England offshore racing, Worldwide cruising - S/V GDY-Kids: 4/2020 back in the US after years in the Caribbeans.
https://www.instagram.com/gdykidscontest/
DeValency is offline   Reply With Quote
Old 17-10-2020, 04:55   #6
Senior Cruiser
 
GordMay's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 42,587
Images: 241
Re: Where to position vented loop, exhaust or intake side

I realize the issue has been resolved, but FWIW.
See ➥ https://www.cruisersforum.com/galler...r&imageuser=79
And ➥ https://www.cruisersforum.com/galler...r&imageuser=79
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 17-10-2020, 10:10   #7
Registered User

Join Date: Apr 2012
Location: Currently in Spain
Boat: Island Packet 420
Posts: 389
Re: Where to position vented loop, exhaust or intake side

And, make sure the vented loop is above the waterline, even when heeled.
sailing_gal is offline   Reply With Quote
Old 17-10-2020, 10:22   #8
Senior Cruiser
 
DeValency's Avatar

Cruisers Forum Supporter

Join Date: Oct 2018
Location: Boston
Boat: Farr 40 (Racing), Contest 43 (Cruising)
Posts: 732
Re: Where to position vented loop, exhaust or intake side

The drawings here show the loop but not the vent. A loop only will not prevent a back flow at some heeling conditions! A vent must be installed.

I don’t like the loops with a valve, these tend to clog. The better solution is a small heat resistant tube (copper, silicone...), that can go even higher and discharge into the cockpit drain (that’s the original at my center cockpit) or outside.
__________________
New England offshore racing, Worldwide cruising - S/V GDY-Kids: 4/2020 back in the US after years in the Caribbeans.
https://www.instagram.com/gdykidscontest/
DeValency is offline   Reply With Quote
Reply

Tags
exhaust

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why are vented loops vented outside? BobHorn Plumbing Systems and Fixtures 18 13-07-2020 10:32
Why turbo wash the intake when exhaust side is dirty? Jeanneau 45.2 Engines and Propulsion Systems 11 26-04-2018 17:20
Marelon Vented loop suitable for exhaust? SV Demeter Engines and Propulsion Systems 2 02-04-2012 10:59
Plastic Anti-Siphon Valve for Vented Loop Dick Locke Plumbing Systems and Fixtures 4 17-07-2009 22:49
2" Vented Loop Source Stevens 47 Plumbing Systems and Fixtures 31 20-02-2009 08:45

Advertise Here


All times are GMT -7. The time now is 08:58.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.