SCWD repair version 2 2/20/08

I go through a SQWD about once every 4 months so I decided to try and rebuild one. After searching the internet I see a couple people have modded them so I decided to give it a try.

Initially I thought I would go with the use of a 1 1/2" cleanout as the body replacement as done by some other DIYers. I ended up cutting the body a little to short so this one is going to go back together with the original body parts and a self made adaptor to glue the parts together.

It seems most of the SQWDs go bad by either getting sand stuck in the them or the diverter plate breaks. Oddly enough this first attempt of mine has the main impellor seperated from the shaft. So after cleaning everything in some bleach and then vinegar and giving all the parts a good scrub I'm going to attempt to superglue the impellor back to the shaft. If it doesn't hold I may try to fuse it on.

here are some pics of the parts I was going to originally use so you can get the iidea.

here is the adapter ring I made to put the two part back together

here is the internal geared assembly all together - the impellor on the left is what came off

here is the gear assembly taken apart. It's pretty slick, each of those gear assemblies must reduce the rotations by 3 or 4 times. I'm guessing not counting gear teeth. If I'm correct, or close, for every 100 impeller rotations the first set of reduction gears would turn 33 times, the second 11, the third 4 and the last set once. So it would be about a 100 to 1 reduction (again guessing not counting)

the picture has all the parts cleaned up after soaking in vinegar and the main impeller has been glued and is drying. So far it turns freely with a breath.

while the glue is drying I decided to test fit the body parts. I also reamed out the openings with a 1/2" drill bit. From what I've read this should improve the flow some.

I decided to test run the impellor / gear assembly. I t seems to be working fine but I'm going to wait over night before gluing just incase that impellor glue doesn't set completly and I have to fuse it. Here is a video of the test run. You may be able to make out how fast the impellor turns in comparison to the diverter.

http://www.youtube.com/watch?v=-xhnuaUAS20

[Marc]

You did a great job in that assembly. I hope it holds tightly without any leaks. It almost seems like it should be something you can take apart from time to time.

You did a great job in that assembly. I hope it holds tightly without any leaks. It almost seems like it should be something you can take apart from time to time.

I am very concerned about leaks. Given this is my closed loop on the bottom of the tank a leak would be bad, very bad .

I may or may not use this. Initially I wanted to install a removable or screwed device to give me future access. I have a couple dead SQWDs so I can play with them. Here are some thoughts:

1) Using the existing body but replacing one end with a threaded fitting for access to the gears for maintenance. I've seen a couple designs on this.

2) Making a larger body "Super SQWD" out of PVC parts that allows for more flow and access. There is one in the DIY forum on Reefcentral.

Initially, I wanted to go with item 1 above. But when I cut the body a little short I decided to just fix and reseal the exisitng body. I wanted to get this done yesterday, but after finding what was wrong and wanting the glue to set for more then a day, I may go back to my original desire. I'll just need to get some different parts.

Or, I'll continue with this as is. Then build the removable version on a second busted SQWD. And then gut this one out later for the super SQWD in item 2 above.

What ever I do I will test for leaks and integrity prior and after installation.

At the end of the day I may end up going with a oceans motions anyway but I figured I'd play with the SQWD mods befor that investment.

I'll continue to document progress and lessons learned on this post so others can chime in with their experiances or learn from mine

[Marc]

That sounds like a good plan.

Do you think that perhaps you could somehow use a Union as the center piece, that way it could always be taken apart when necessary?

Do you think that perhaps you could somehow use a Union as the center piece, that way it could always be taken apart when necessary?

that very thought kept me awake last night

next time I'm at a hardware store I'll have to take a close look at them, my thought is they may be to long even after cutting. But maybe if I just use the flanges and a very short piec I could work it in.

the reason I say I cut the body too short was the guide inside the body holds both the diverter piece and gear cylinder. The cut I made only allowed for the guide to hold the diverter.

I have been bouncing a couple ideas around, for example, maybe use that coupling I made, then a short piece of body for the guide and then a screwed connection like I initially intended. But, now that you mention it, I want to check on the union route again. If I can get it to dimensionally work out, it would provide a better solution to future access.

[Marc]

I wonder if you could make your own holder within a union permanently, slip the gearwork into that, and connect plumbing like normal.

I do know in those RC threads there was discussion about too much flow eventually circumventing the scwd mechanism, so you will have to find what works vs. what is excess.

Now there you go and get me thinking again. I like the concept, maybe the super SQWD like I saw on RC but with a union body instead of a screwed coupling.

As for the oversize to overflow. I would want to keep the inside chamber about the same size but just open up the inlet and outlet a bit.

now I'm thinking the super SQWD could be 4 outlets. I'm leaning toward taking the SQWD and cut off all of the inlets and outlets so they are just openings. Then drill two more outlets so total 4. Still cut the bioy in half and encase each half in a proibably a 2" cut down union. Reduce down to the inlet and build a 4 way outlet pipe with a sch 80 (for thickness) outlet body that has 4 openings with threaded connections (or maybe socket) with 3/4 pipe outlets.

[Marc]

Less talkin', more moddin'.

I'll swing by the hardware store on Friday and pick up a couple unions (2" and 1 1/2") to see if your idea will work.

I picked up the unions. The 2" fits ovver the body but is huge and will make it dificult to hook back up. After several consideration I have come up with a union modification on the 1 1/2" that I thik will work just fine. It will include making some cuts on the union and will require a hole saw cut to lenghten the socket depth on one end.

[Marc]

Looking forward to all the pictures.

Problem

Using a 2" union is too big. the 1 1/2" does not proved enough space to remove/install the gear/diverter assembly therefore defeating the purpose of installing it. I can go back to my original design as a one time fix or may incorporate a rear access port with a 1 1/2" cleanout fitting to remove the diverter valve.

her are some pictures of the body union rough fit up. So far, it looks like it will work fine. I'll work on the back access next. I had to notch the connection to preserve the internal support

the union mod works but I lost too much of the internal guide and the gear assembly doesn't appear sound enough for me to want to use it. I could add some more guides, and I may go this direction eventually but for now I think I'm going to retire this mod and work on two other versions

1) a simple, cut off the back side and add a 1 1/2" cleanout for access

2) the 2" PVC complete new body version from Reefcentral

here is version 2 of the mod - I exanded on just cutting off the back for cleaning the diverter. this version gives access to both ends

To start, I cut off both ends

Replaced the back (diverter) side with a trimmed 1 /12" PVC cleanout & plug

On the inlet (gear) side I replaced the original nozzle with a trimmed 1 1/2" SW X threaded union. Then added a 1 1/2" X 3/4" reducer and a 3/4" threaded tubing adaptor.

and here is the whole thing put together, I tested it and it works fine and may install it later this week

[Marc]

Amazing progress. Be sure to apply some silicone grease to the threads so open it more easily in the future. I also put that on the threads of unions.

Amazing progress. Be sure to apply some silicone grease to the threads so open it more easily in the future. I also put that on the threads of unions.

Marc - would you use the silicone grease instead of teflon tape?

[Marc]

The grease is to make it easy to unscrew, not to seal it. You can seal it with teflon paste or teflon tape.

I wonder if grease and tape work, so you have a seal that isn't impossible to open later.