05-27-2020, 09:46 AM
I recently repaired the air water sequence valve in our Microphor LF210. The following are hints from my experience.
- When you order the air water sequence valve overhaul kit PN 95187 it will convert the older style black valve open top end cap to a closed end cap. This is done with replacement of the internal spool stem, the addition of an end plug and an end cap that does not have a hole in it. This eliminates a water leak failure point where the older style stem would protrude from the end and required an o ring to seal it. See yellow arrow in picture.
- The gray body valve is the newer part and much more robust than the older black valve. If converting from the black valve to gray you have to transfer the air fittings. Do not use teflon tape to seal the fittings, use plumbers putty. These fittings can be over tightened easily and crack the valve body. They do not need to be super tight, just snug.
- Both the black and gray valves have a top and bottom joint to the middle valve body. When you install the top portion of valve to middle portion it does not need to be super tight. Doing so will crack it. This connection does not seal water or air. It is just a mechanical bond between the two parts. If you are just taking apart the valve to clean and lube it I suggest you make two index marks on these threaded areas. Then upon reassembly, stop at the index marks.
- The bottom end cap to middle valve body is sealed with an o ring. ( see green arrow ). When you screw this joint together the gray valve body has to pass past this o-ring to seal. This creates a binding point during assembly. If you stop short of going all the way past this o-ring, the internal operating piston can travel farther than it is supposed to and the valve will not work correctly. If you tighten the bottom end cap enough to get past the o ring and bottom out the gray body you can then over tighten the bottom end cap and crack it. The answer is to first remove the sealing o-ring ( green arrow ) and then screw on the bottom end cap till the body bottoms to the end cap. Then make Sharpie index marks ( Red arrows ) noting the point where it's just at the end of its travel together in the joint. Then unscrew the joint, reinstall the o-ring and reassemble by tightening to the index marks only. It will help to lube the o-ring with silicone.
- The bottom air fittings going into the valve body can easily damage the valve if they are over tightened into the valve plastic. The threads can be pulled or the body plastic will crack.
- The internals of the valve should be lubed with silicone grease. This includes the o-rings, spool stem.
- The water inlet and spud outlet fittings can crack the plastic of the valve if over tightened. Use caution here as well.