For those that have one, do you know what kind you have? Vetus makes a few - https://www.google.com/search?q=vetus+vented+loop - and there are the Forespar Marelon ones. I read some of the Vetus ones require running a vent line overboard or to a cockpit drain, or they leak water into the boat.
Also where do you have it mounted / how high? My mechanic suggested mounting it as high as possible, which means running it up into the stbd lazarette. I'm hesistant about that because our lazarette is jam packed full while cruising (it's our only large storage space).
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray