replacing seacock valve-gctid802349

[Guest]

The thru hull fitting looks good but that seacock valve was frozen. I remove the old valve. The thread from the thru fitting is good. Trying the replace with new seacock valve.

My question is when threading in new seacock valve to fittings, do I use 3m sealant on the thread or teflon tape for the threads?

[boatworkfl]

"simjun" post=802349 wrote:
The thru hull fitting looks good but that seacock valve was frozen. I remove the old valve. The thread from the thru fitting is good. Trying the replace with new seacock valve.

My question is when threading in new seacock valve to fittings, do I use 3m sealant on the thread or teflon tape for the threads?

Use a sealant! Not Teflon.

[Mr._Darcy]

I agree with boatworkfl, use a good quality sealant. Make sure the threads are clean and flawless before reassembling. Carefully use a thread file and wire brush to clean and smooth as needed. And as my brother would say, lightly turn it a couple of turns counterclockwise to hear the threads click, then while keeping it aligned turn clockwise gently to engage the threads. This technique, ritual or whatever, has prevented cross threading for many years for mechanics and plumbers. Our grandpa, who was a millwright, did it too. Buggering up the threads on a through hull can get expensive in short order.

Greg

[Norton_Rider]

Are you using a real seacock or a ball valve? If using the later, keep in mind that thru-hulls have NPS threads and ball valves have NPT threads. A ball valve will thread on a thru-hull for a for a few turns, but not enough. This creates an unsafe situation. Unfortunately many manufacturers and boat yards use ball valves on thru-hulls. Many older Bayliners were this way. Here are some good articles:

http://www.sailfeed.com/2013/10/no-n...-and-seacocks/

http://www.pbase.com/mainecruising/s..._primer&page=1

[boatworkfl]

"Norton Rider" post=802352 wrote:
Are you using a real seacock or a ball valve? If using the later, keep in mind that thru-hulls have NPS threads and ball valves have NPT threads. A ball valve will thread on a thru-hull for a for a few turns, but not enough. This creates an unsafe situation. Unfortunately many manufacturers and boat yards use ball valves on thru-hulls. Many older Bayliners were this way. Here are some good articles:

http://www.sailfeed.com/2013/10/no-n...-and-seacocks/

http://www.pbase.com/mainecruising/s..._primer&page=1

One of the best explanations of the difference between a correct seacock and a standard ball valve thru hull.

[Guest]

I check under the boat. The thru hall fitting for the a/c function is a high speed pick-up. The flange nut is secured with nps thread pattern, on the top part the thread pattern changes to npt. Please confirm if your boat has this high speed pick up fitting.