well here I am again... almost a year to the day. Same symptoms . Compressor will not build pressure. Blowing off thru pneumatic unloader... Brownac1983 do you think the spool piece could have failed in a year ? Gonna take the hyd unloader off today and give it a look. Why do things break down when you need them the most ??? Murphy ???

thanks
john

 

. went out and removed the hyd unloader and looked at the pieces... the rubber seal in the spool looks like i's broken down and it's top is even with or below the top of the brass of the spool. Seems like it should be a little bit proud of the housing...see pics

might as well order a new rebuild kit and get it on the brown truck asap... any guess what makes these rubber seals break down so fast ???

 

What oil are you using Quincy oil?
I never had that go bad on the ones at the hospital I worked at it was always the rubber diaphragm under the mushroom thing at the top.
With the heat the head gives off it dries out and cracks.

I also like your air dryer.
It looks like it is between pump & tank? How good does it work?
I also have a dryer but it is after the tank and before the piping around the shop.


And as a last stop for the water each of the 5 air drop / hose connection has a drip leg.

Dave ----

 

thanks for the reply

 

It could be the synthetic oil, but then again maybe not. I'm not sure what those seals are made of. Did you replace the spring when you rebuilt it? If not, you might try that, it could be chattering. Those seals should last at least a few years even with constant use. But if you depend on your compressor keep a couple on hand.
-Drew

 

Is the synthetic 30W that you're using specifically an air compressor oil?

 

.
yes Drew... replaced spring, piston and rod. I can easily change back to dino oil.. it's just a quart or so... got a rebuild kit on order, waiting on brown truck.

john

 

not compressor oil..just generic syn... Castrol if I remember correctly

 

It shouldn't have anything to do with this issue, but in general you want to use a non-detergent oil for compressors. Auto oils contain detergents that are designed to keep dirt and debris in suspension so the oil filter can catch them. On applications without an oil filter (compressors, small engines, etc), you want a non-detergent oil so any dirt or debris settle to the bottom instead of stay in suspension to be repeatedly splashed onto the cylinder walls. You can buy purpose-labeled compressor oil, but any non-detergent oil will do. It's not going to hurt anything short term, just something to keep in mind for the next change.

 

It cold be the oil like brown pointed out and why I asked what you were using.
At the hospital we used Quincy oil on the 2 Quincy compressors and Kaeser oil in the Kaeser screw compressor.
In my home garage the SnapOn compressor I use oil made / marked for air compressors.

It also does not use that same type of un-loader like yours. It uses a check valve just before the compressors out let line that goes into the tank.
That is 1 reason why I did not run the air thru a cooler before it went into the tank like you did.

That check valve was also why I think the compressor was taken out of use. I found the starter control contacts welded closed from trying to start under load, so the unit would not shut down when it got to PSI.
I also had a Craftsman 30 gal that had the same type of check valve that failed and would not let the compressor start.

I think if it was me I would do like you did the last time and rebuild that oil psi loader and replace the rubber diaphragm at the top and use an oil made for air compressors so it would not hurt that loader rubber seal.
Dave ----

 

Agreed. And I'd keep a spare unloader kit on hand just in case. It's only a minor annoyance to rebuild it every year or two if you have the parts on hand, vs. having your compressor down for a few days in the middle of a project.

 

FF so do you think ANY compressor graded oil 30WT ND would do ok ?? i.e. Ingersoll Rand or Amsoil ?? I like the idea of synthetic because of the longer life and less buildup in the pump. Parts won't be here till monday so I got time to find some.,.,,. just hate to order online

 

so update got up to 34 today and I rebuilt the hyd unloader. new valve(piston) and spring and such...reinstalled and it's just as bad... still blowing off at pnum unloader... what to check next ???

 

Check the diaphragm in the pneumatic unloader.

 

If you're in a bind, you can cut one yourself from reinforced rubber sheet. It won't be as good as factory, but it should get you by until a replacement part arrives.
https://www.ebay.com/itm/New-Quincy-...-/271831067801