Compressor hard to start/re-start ?

[theoldwizard1]

This might be old info for many of you, but I just found this. There is a device called a "cold/easy start valve" that might solve your problem.

As close to the compressor head as possible, install a tee and one of these device (eBay <$10; ignore brand). It is sort of a secondary unloader. The valve stay open to atmosphere until it sees 20-25 psi and then closes.

 

[ttpete]

This might be old info for many of you, but I just found this. There is a device called a "cold/easy start valve" that might solve your problem.

As close to the compressor head as possible, install a tee and one of these device (eBay <$10; ignore brand). It is sort of a secondary unloader. The valve stay open to atmosphere until it sees 20-25 psi and then closes.

Most quality compressors have unloaders.

 

[theoldwizard1]

Most quality compressors have unloaders.

Mine has a regular unloader and this ! Why, I don't know.

 

[redmondjp]

Mine has a regular unloader and this ! Why, I don't know.

It helps the pump to get up to speed faster with less load on the electric motor. So they can use the smallest electric motor that they can get away with.

The typical low-end compressor unloader only discharges the pressure between the pump and the check valve at the tank. When the compressor goes to start, that line immediately builds pressure as the unloader valve is closed whenever the compressor is running.

So this additional valve keeps the output line of the pump at a low pressure until the pump speeds up enough for the pressure and flow of air to shut off the valve.

On some of the wheelbarrow-style gas-powered compressors, they have a manual unloader valve that you open while starting the motor, for the same reason: easier starting. Heck, with my 18HP pressure washer, I have to do the same thing (hold the gun valve open while starting) in order to start it.

 

[BUDSVTX]

Air compressor load genie at Granger, works great, have been using them for at least 30 years.

1/4 " SS steel ball valve mounted at the pressure washer pump discharge. Open the valve unloads the pump for easy starting. Older folk do things like this to make doing things easier. I can't pull start my 13HP pressure washer with out unloading the pump head. Also can't hold the gun open in 1 hand and pull start the pressure washer with the other.

 

[theoldwizard1]

Also can't hold the (pressure washer) gun open in 1 hand and pull start the pressure washer with the other.

Yeah, that pretty hard to do, but required, on my cheapy 5 hp PW.

 

[theoldwizard1]

It helps the pump to get up to speed faster with less load on the electric motor. So they can use the smallest electric motor that they can get away with.

It would likely prevent a breaker trip on a restart for a small compressor that ran close to the circuit breaker limit !

 

[gungatim]

interesting...I gave a buddy a compressor 2hp needs 20 amp recept. but he only has 15, when it restarts it is slow and trips the breaker. I thought the check valve or unloader was bad til I realized his circuit was undersized...he doesn't want me to run another one for him so he keeps draining the tank and starting it empty...maybe this item is the way to go.

wonder if it would work as a compression release on a Harley??? or would it re-open on the intake stroke?

 

[redmondjp]

1/4 " SS steel ball valve mounted at the pressure washer pump discharge. Open the valve unloads the pump for easy starting. Older folk do things like this to make doing things easier. I can't pull start my 13HP pressure washer with out unloading the pump head. Also can't hold the gun open in 1 hand and pull start the pressure washer with the other.

Not to derail this thread any further, but that's an awesome idea! And I think I even have one small SS ball valve somewhere in my garage as well.

 

[theoldwizard1]

wonder if it would work as a compression release on a Harley??? or would it re-open on the intake stroke?

It would likely re-open as it is spring loaded. Most compression releases (at least on small engines) use RPM to close them. Some chainsaws have a manual (pull/push it) compression release.

 

[t1r2u3s4t]

where do you install this valve? between the compressor and the tank's check valve?

 

[redmondjp]

where do you install this valve? between the compressor and the tank's check valve?

Yes - as stated in the first post, as close to the compressor head as possible. IMO, anywhere in that discharge line upstream of the check valve will be equally effective.

 

[finn]

It would likely prevent a breaker trip on a restart for a small compressor that ran close to the circuit breaker limit !

Possibly helpful on a jobsite that requires q long extension cord / big voltage drop.