wrote: Randy, Perplexing... While I have certainly noted the pressure in the low side rise and fall from thermal influence when parked in the hangar(up to ~1000 psi), I do not recall having the high side follow this trend. In the extended position the lowest resistance path to the reservoir has been closed off. Theoretically both sides could hold pressure, up to relief valve settings, if pressurized by some means. The high side would lag very far behind since the entire high side circuit would be depressurized and hoses completely relaxed before any thermal influences would start building pressure. I can run another hair dryer test on the bench similar to what I did to demonstrate the up-side behavior with thermal heating and cooling of the cylinders. I'm not sure what to expect. As far as momentary pump starts are concerned. I have such an over-ride circuits built right into the panel. They are nothing more than momentary push buttons that jumper across the pressure switches. These were installed during the time of a previous generation of pressure switches which had a habit of sticking open. Chris Chris Zavatson N91CZ 360std www.N91CZ.com --------------------------------- Ahhh...imagining that irresistible "new car" smell? Check outnew cars at Yahoo! Autos. --0-1465605381-1176920020=:18971 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit

Chris,

In this instance I am not sure what either side was doing as I did not look at the pressure gauges. I belive the low side was very high. High enough to make the 0-1200 psi range gauge fail. I am guessing 2000 or so. I am not sure why the pump would not come on in this condition unless the high side pressure was above 1300.

I plan to replace the guage on the low side and do some gear testing.

I will monitor the gauges when those same conditions exist again and post what I find.

Randy Snarr

"Zavatson, Christopher J (US SSA)" <Christopher.Zavatson@baesystems.com> wrote:

Randy,

Perplexing...

While I have certainly noted the pressure in the low side rise and fall from thermal influence when parked in the hangar(up to ~1000 psi), I do not recall having the high side follow this trend. In the extended position the lowest resistance path to the reservoir has been closed off. Theoretically both sides could hold pressure, up to relief valve settings, if pressurized by some means. The high side would lag very far behind since the entire high side circuit would be depressurized and hoses completely relaxed before any thermal influences would start building pressure.

I can run another hair dryer test on the bench similar to what I did to demonstrate the up-side behavior with thermal heating and cooling of the cylinders. I'm not sure what to expect.

As far as momentary pump starts are concerned. I have such an over-ride circuits built right into the panel. They are nothing more than momentary push buttons that jumper across the pressure switches. These were installed during the time of a previous generation of pressure switches which had a habit of sticking open.

Chris

Chris Zavatson

N91CZ

360std

www.N91CZ.com

Ahhh...imagining that irresistible "new car" smell?
Check out new cars at Yahoo! Autos. --0-1465605381-1176920020=:18971--