Question about regulator pressures?

My Huben has 2 gauges - one for the air cylinder and one for the regulator volume chamber.

After rebuilding the regulator - replaced the o-rings and lubed up the bellevue washers, I've been keeping an eye on the gauges looking for leaks, etc.

Over the past week, the air cylinder gauge has been steady at 185, but the regulator gauge has been dropping slowly, first 170 and now a week later 160. Is this just the regulator "settling" in after the rebuild or is there a leak? Or is this so-called "regulator creep". I would have thought with a leak somewhere in the gun, the gauge on the air cylinder would drop too? :unsure:
 
What was the reg pressure set to before your maintenance? Is it returning to this value consistently after a few shots? I'm assuming the Huben's regulator design allows cleaning and lubing without disturbing the piston spring setpoint adjustment.

Regulator creep usually overpressurizes the plenum above the regulator set point. Gradually at first and then faster and faster so you would see it rising continuously after shots and not rising to set point and staying steady. A regulator set point of 160 or 170 bar sounds a little higher than most. Do you know what it should be according to your notes and past setup?

If your plenum is leaking either due to an o-ring or the valve assembly, I would think it would equalize with the reservoir pressure gauge at some point and they would both bleed down together. Your reservoir gauge and regulator/plenum gauge may not actually agree even if there is the same pressure due to variations in gage calibration.

When you re-lubricated and reinstalled your o-rings on the regulator, did you lube the entire ring including the gland where it sits in the groove? In other words, did you install the O-ring dry and then pat some grease just on the OD? Maybe the regulator was creeping a little bit at the very beginning after reassembly and is now settling down to its set point as the o-rings settled and sealed. If properly fitted and lubricated, and not cut during reassembly, the O-rings should seal properly immediately.

Just brainstorming here good luck.

Feinwerk
 
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What was the reg pressure set to before your maintenance? Is it returning to this value consistently after a few shots? I'm assuming the Huben's regulator design allows cleaning and lubing without disturbing the piston spring setpoint adjustment.

Regulator creep usually overpressurizes the plenum above the regulator set point. Gradually at first and then faster and faster so you would see it rising continuously after shots and not rising to set point and staying steady. A regulator set point of 160 or 170 bar sounds a little higher than most. Do you know what it should be according to your notes and past setup?

If your plenum is leaking either due to an o-ring or the valve assembly, I would think it would equalize with the reservoir pressure gauge at some point and they would both bleed down together. Your reservoir gauge and regulator/plenum gauge may not actually agree even if there is the same pressure due to variations in gage calibration.

When you re-lubricated and reinstalled your o-rings on the regulator, did you lube the entire ring including the gland where it sits in the groove? In other words, did you install the O-ring dry and then pat some grease just on the OD? Maybe the regulator was creeping a little bit at the very beginning after reassembly and is now settling down to its set point as the o-rings settled and sealed. If properly fitted and lubricated, and not cut during reassembly, the O-rings should seal properly immediately.

Just brainstorming here good luck.

Feinwerk

Thanks for reply. I took apart all the washers one by one, lubed them, then restacked them. Regulator was set at 170bar before. Higher than my other guns but Huben recommends running it 150-18bar. I shall keep an eye on the gauges next week. Hopefully its just the bellevue springs settling in.
 
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FWIW, silicone grease or oil on the Bellevilles is functionally equivalent to no lubricant.

The rim of Bellevilles will frequently see loads of 100 - 500lbs, and although there is only an infinitesimal amount of lateral movement as they cycle, I like to apply the faintest amount of lubricant to them when I'm servicing a regulator. They do not see high pressure air so there is no concern with using a hydrocarbon-based lubricant like SuperLube synthetic or CorrosionX.
 
In have a very
FWIW, silicone grease or oil on the Bellevilles is functionally equivalent to no lubricant.

The rim of Bellevilles will frequently see loads of 100 - 500lbs, and although there is only an infinitesimal amount of lateral movement as they cycle, I like to apply the faintest amount of lubricant to them when I'm servicing a regulator. They do not see high pressure air so there is no concern with using a hydrocarbon-based lubricant like SuperLube synthetic or CorrosionX.
I have a slow leak on my Huben. I just bought it from Kelly at Krazykool 11 months ago. I have had no other problems with the air rifle. Could you give me some advice? Thank you.