Ok here it goes, I have a powermatic, two in hose all the way to an aw29 with a holed glide, I run the rpms on the machine at about 27 to 2900 rpms and when the wand is on the carpet doing its thing, the vac guage only reads about 8 sometimes 9. What gives, am I doing something wrong? Do I have the vac relief adj wrong? Please edumacate me. I am getting ok dry times but I want them to be better and I just want my machine to be running at tip top performance. Any ideas or tips would be greatly appreciated. Blessings to you! Don Gray
I would inspect for vacuum leaks. Make sure your vacuum relief valve is set properly to what your machine's manufacturer suggest to set it. What does the gauge do with 100 ft. of hose on it and you put your hand over the hose to seal it? Has it always done this or did it just recently start? Do you know for sure what rpm your machine is rated to run? My Boxxer 421 is rated to run at 3000 rpm with a 21hp B&S engine, but I think I'm running 3100.Both my engine and blower are rated to a top rpm of 3600, but I don't feel it's wise to bump it up that far. I'm fixing to put a tinytach on mine to see just how fast it is running. Under normal circumstances my gauge will read about 10 with just the hoses and wand attached. When the wand makes the seal at the carpet it will rise sometimes enough to trigger my vacuum relief valve on the waste tank which I have set at 14 hg. If you have another wand you might want to see if it does the same thing with it or just remove the glide and see if it does the same. On some carpets your glide might not be making a perfect seal, but that shouldn't happen all the time.
Its not a clog because you are only getting 8"hgs It sounds more like a bad waste tank seal or a Vac Rel. Valve that is not adjusted right. You are leaking air somewhere it the system if you had a clog your vac guage would go to what you have it maxed out at 12-15 hgs. is where it should come in at.
I was having the same problem last night and then I realized that it is my gauge that is stuck at 8. So I have no idea at all what I am actually pulling. So time to take it in.
I just had to put a new vacuum gauge on my Boxxer 421. Many suppliers carry them and it should be a fairly easy diy fix. Just make sure you get the same size gauge as is on your machine. I've never seen one stick before, but anything is possible.
Tapped on the glass and it dropped to 5 tapped on the glass again and it went up to 10 tapped again and it went to 8.
it could be the waste gate valve. Indicated by a gurgling sound in the tank while at any rpm. Its a brain fart thing we all have done once or twice aftewr long days work. or.. check to insure the teflon seal isnt DOA on the valve.
Get a secondary gauge and test the vac inlet and compare the two readings. Could be the cap on the gauge that needs to be opened to let air in. Check the connection and line at the gauge and relief valve. Could be a number of things. Dont fiddle with the relief valve unless you are 110% that is it. Tapping on the gauge and then a change indicates something screwy with gauge.
Check the guage reading with no vacuum hose or tools connected. Take not of the reading. It should be low, maybe 3 or 4. Then put your hand or a piece of cardboard over the vacuum outlet. Note the guage when the vacuum is fully restricted. This reading will be approximately where your vacuum releif valve opens, maybe 15". The difference between the high and the low reading is the vacuum power you have available to work with. That is what really matters. The reading with your hoses and wand attached simply indicates the amount of restriction offered by the tools that are attached.
