vac plugged up all of a sudden how to fix it?

[knight_toolworks]

it was working fine for months then all of a sudden I show almost full vac with one or all gates opened. so it has to be plugged up right before or in the t I guess. Since the pressure gauge is right after it. I put a coupler right at the end of the black pipe took it off and airflow is fine before it. but there is not much meat left if I cut right at the elbow. I tried putting a wire down it but who knows with all those turns.
http://i154.photobucket.com/albums/s266/knighttoolworks/posting/0573FBFC.jpg

[knight_toolworks]

Ok this is weird as I was afraid there is no plug but it only cost me a couple of elbows. I just surfaced the top could that somehow have done it? I was able to remove the piple after the first valve and there is plenty of air movement. it's like the spoilboard is blocking all but 2" or so of air. even with nothing on the table and all 4 valves open I have almost above normal pressure then if I had a sheet of stock on the table.
I have two gauges so one can't be bad since they read the same. its really like I sealed the spoilboard.

[Brady Watson]

Disconnect it @ the vac & blow it out with a shopvac blower or compressed air...When you get it all clean, put an inlet filter on it! Hooketh thy self up...

-B

[knight_toolworks]

I have a filter box before the vacs. But I doubt all 4 inlets could plug up at the same time. I mean they were fine this morning till I surfaced the table.
I took one pipe off after the valve and it is clear. it would take a lot to plug up a 2" pipe. when there was nothing there when I redid my tabletop. I am able to disconect the pipe right up to the valves and there is no plug after the filter. it has to be the top stopping it. all four zones are affected and there is no plug leading to the valves.
I only lose 1 or 2" opening all 4 valves right now.

[knight_toolworks]

right now I don't have a shop vac that blows. I thought about doing that but I forgot about the airhose. but it seems impossible all 4 inlets plugged up all at once.

[danhamm]

Use the dischsrge of your vac system or your dust collection system..

[knight_toolworks]

too hard to get the air to the right pipe. plus there is not a lot of pressure.
but I will use compressed air. but I can't think there is anything large enough to clog the pipes. I mean how would it get there in the first place? there was nothing when I put the top on.

[jerry_stanek]

after I surface my spoil board I blow it out by hooking my vacs up to blow a lot of dust comes out.

[gene]

Have you surfaced both sides of your spoilboard? also check your filter if you havent allready

[knight_toolworks]

Yes I surfaced both sides. I have surfaced this spoilboard for the second time after I flattened it after installing it. but last time I forgot to turn on my vac and the top was not flat. this time I surfaced it with the vac on. So I am thinking somehow it plugged it up. I have never had this happen before but it sure baffled me.

[knight_toolworks]

after I surface my spoil board I blow it out by hooking my vacs up to blow a lot of dust comes out.
that's what I am thinking is the problem. I will try it out today.

[knight_toolworks]

Ok I am clueless. I decided to redo the piping as it was such a wacky job with the filter box. I removed the filter box because of the bulk of it. well all works just like it should now. I had tested the airflow after the filter box last night and it was fine. I took the box apart and the filter is not plugged up. so I have no clue what was going on. I almost fried one of my motors. it rattles if it pulls too much vac glad I ordered the pressure relief valves.

I am going to all rubber sleeves and clamps for joints I want to take apart. the screw joints are expensive and a real pain to reconnect if things don't line up perfectly. But I had a couple I could reuse for the flex hose.
http://i154.photobucket.com/albums/s266/knighttoolworks/posting/1470723b.jpg

[Brady Watson]

I see big spring loaded check valves in there...they are less than desirable. The 'flap' type sewer check valves with no spring are best since they require next to no pressure to close. Also - you are totally killing your CFM potential with all those bends in the system. Each 90 degree elbow is equivalent to about 5 or 6 feet of 2" PVC pipe. EACH elbow will reduce your airflow by at least 10% of the overall system CFM - count them out...how much are you losing?

It could be one of those check valves got stuck?

-B

[michael_schwartz]

I see big spring loaded check valves in there...they are less than desirable. The 'flap' type sewer check valves with no spring are best since they require next to no pressure to close. Also - you are totally killing your CFM potential with all those bends in the system. Each 90 degree elbow is equivalent to about 5 or 6 feet of 2" PVC pipe. EACH elbow will reduce your airflow by at least 10% of the overall system CFM - count them out...how much are you losing?

It could be one of those check valves got stuck?

-B

So what would be a realistic number of elbows to aim for. Something like 1-3 max to get to any one zone?

[Brady Watson]

So what would be a realistic number of elbows to aim for. Something like 1-3 max to get to any one zone?

2 per zone is ideal...You have to give up some CFM in order to get the vacuum plumbed, but extra elbows, tees and bends should be avoided. After you get over the hump and start to build vacuum pressure, this is really not much of a concern. The times when it is a concern is when a customer brings A/C plywood that is like a potato chip and that extra CFM can make it or break it to get the initial seal.

Zero elbows is best...especially if you are using Lighthouse motors.

Support board 2" hole - filter - vacuum motor.

Bear in mind that it is tough to prove the 10% (some say 25%) estimate on the elbows without some fairly specialized equipment. I do know that elbows and bends do make a big difference on intake manifolds and exhaust systems...both of which flow air, just like our vac systems.

-B

[knight_toolworks]

I see big spring loaded check valves in there...they are less than desirable. The 'flap' type sewer check valves with no spring are best since they require next to no pressure to close. Also - you are totally killing your CFM potential with all those bends in the system. Each 90 degree elbow is equivalent to about 5 or 6 feet of 2" PVC pipe. EACH elbow will reduce your airflow by at least 10% of the overall system CFM - count them out...how much are you losing?

It could be one of those check valves got stuck?

-B

I thought at first it was the valves but both seemed to work and I got suction past them. They were both before the filter box. Now I have two elbows and a t to the valves that's about the best I can do. but setup befroe the plug was real wacky and I could only get 5" max now I can get 7 to 9or more depending on what motors I use.

[knight_toolworks]

ok today I got the same full vac thing going on. though not quite as bad. but still with all for valves open I am still get 5"
So I figured it had to be the check valve though I wondered how it could be two of them. replaced it with straight pipe and it is still a problem. I resurfaced the spoilboad and all is fine. for now anyway.
but I did get these guys so I can make sure they are working http://www.amazon.com/King-Brothers-Inc-KSCC-2000-S-2-Inch/dp/B001OE1AB4/ref=sr_1_43?ie=UTF8&qid=1332272824&sr=8-43
well yes it was better but still I had to open another gate to keep the pressure down. I think the only solution is to remove the surface till it stops or replacing the sheet.