Watts Manifold Leaking

FB

There's a really slow leak - 3 or 4 drips an hour- at the hex shaped top of one of the 3/4" BSP threaded fittings on the underside of the supply manifold. A gentleman at Watts was able to confirm that these fittings are screwed onto cylindrical protrusions on the underside of the manifold. Unfortunately, he did not know what provides a seal between the fitting and the cylindrical protrusion. Each of the fittings has a bit of what appears to be fibrous black packing or gasket material poking out of the threads, visible just above the hex. Watts catalogs list several gaskets for sealing the BSP manifold connections but nothing for the threaded connection that's leaking. Have you ever removed one of these fittings and examined the type of seal? Before draining the system and applying wrenches, I'd like to know what to expect. Thanks in advance for any advice.
Fred

SWEI

Assuming that's a Eurokonus fitting, there is an O-ring that fits a groove in the face of the dome-shaped end of the part that fits into the tube. The threads do not use a sealer.

hot_rod

Dry it with a Kleenex and make sure it is not leaking from above, if it has an actuator above it is more common to find an O ring leak at the stem, running down.




Most straight thread connections are assembled with a gasket AND Loctite, that is the case here. A red tapered cone washer and red loctite.

Might be tough to find that washer, a new O ring, dry everything and Loctite it together. If the red cone washer is ok just reseal with thread locker.

Loctite 545 is best if you can find a small squeeze tube, it is for hydraulic and pneumatic pressure applications.

SWEI

Oops -- my bad. Wrong threads!

An anaerobic threadlocker (e.g. Loctite 545, 565, 567) would be the easiest and most permanent fix. Someone here mentioned a heavier bodied option (Hernon Dripstop 923) a few months back, which may be better at filling large gaps.

hot_rod

In this case I would use a "glue" like the Loctite.
272 is a heavy body version for loose threads, but not as permanent as 575.

That Hernon Dripstop look like a high tech teflon, the fitting could un screw when the pex connection was worked on unless it is glued together.

Ideally the correct gasket makes the seal, the locker just keeps it all together, not much more than finger tight to make an o-ring seal with straight threads. Over tightening distorts the gasket or O-ring, usually a torque tool is used in those assemblies, to get the perfect "squeeze" on the gasket or ring.

Same with ball valves, when they are assembled they use a locker, else the valve would dis assemble at the seam when you un threaded the pipe from IP valves.

BobC

Using the right sealant is important.

Back in the mid seventies the company I worked for made a series of power supplies that was used by the navy and air force. There were 8 different supplies that ranged from small dual output supplies to large 22" rack mount units that had a dozen outputs.

Several of the supplies used a small "oops" board in the overvoltage interface that fed the SCR's. This board was about an inch square and had 6 components on it, it mounted via a single swaged 2-56 standoff. The board was usually tucked in between some large can caps.

Because this equipment had to pass stringent vibration requirements all the hardware was loctited.

The problem was they used the red loctite that was VERY good at sealing threads but a bear to break loose if it was used on small screws. Remember that 2-56 standoff on the board that was buried in the capacitor back, it was mounted with a nice little slotted flat head screw. You could not apply enough torque to the screw to break it free without it also breaking free of the small printed circuit card it was swaged onto. All you could see from the inside of the chassis was the backside of the pwb with the 2-56 standoff swaged into it, if you applied enough torque the standoff would start turning in the board. You couldn't apply heat because that would destroy the finish on the chassis.

The only choice was to break the board in half, grasp the standoff with pliers and remove that screw (with great difficulty). The folks who had to replace that board were not happy, I told them to use the green loctite that was not nearly as tenacious.

They didn't listen to me so I snapped four more boards in the next week. The guy who ran the rework department went to the owner to complain about what i was doing and i was called into the office. I explained what I had done and told them I had added a note to the assembly print (via ECO) with the correct loctite called out.

The boss told the head of the rework department to listen to me or get used to replacing the little boards - he was not happy.

Bob

hot_rod

Good story! Yeah use the Loctite support to select the right product, some come apart easily, others not at all

SWEI

Henkel sells a LOT of Loctite variations. They sell through multiple divisions, which can make comparing them somewhat difficult.