Checking crank seals with Freon.

[gsonwg]

So maybe I’m an idiot or maybe I’m on to somethin. Last I time I was checking seals I rigged up a way to use my air conditioning gauges to read the pressure so instead of air I carefully pressurized with 410a and then used my audible leak detector to check for leaks. Those seals happened not to be leaking so I could not really see if it for sure worked. However I did find that my leak detector picks us gasoline fumes so it can throw a false flag. Seem like a good or bad idea?

 

[pioneerguy600]

If you already have the gear, why not. On the other hand I wouldn`t go out and buy it all just to service chainsaws. Any pressurized gas would work, ie oxygen, co2, argon helium etc but plain compressed air is likely a cheaper route for most of us.

 

[sean donato]

Wouldnt go telling a lot of people about that, if your into hvac you know how anal they are about recovering refrigerant these days.

 

[gsonwg]

No need to recover it. I leave it in the case so if the saw freezes up I know it’s low and must have a leak. If I knew how I would insert a laughing smiling face to let everyone not into hvac that it’s a joke.

 

[ironman_gq]

No need to recover it. I leave it in the case so if the saw freezes up I know it’s low and must have a leak. If I knew how I would insert a laughing smiling face to let everyone not into hvac that it’s a joke.

Propane is R290, your sniffer should detect that just fine and it's a lot cheaper than other refrigerants.

 

[gsonwg]

I use propane to test all my old r-12 stuff for leaks and run em for a little while to make sure before I fill em with crazy expensive 12. My sniffer is old and for some reason will only pick up propane if it’s a big leak.

 

[lone wolf]

Wouldnt go telling a lot of people about that, if your into hvac you know how anal they are about recovering refrigerant these days.

Only about large amounts they cant be bothered about small stuff!

 

[sean donato]

Only about large amounts they cant be bothered about small stuff!

The new (at the time) standard made our old machines obsolete because they didnt recover enough refrigerant. I cant remember the J spec it fell under, was a pain. The spec sent into effect right before the new r1234yf hit the market. We switched to pressure testing with nitrogen after the system has been evacuated, to prevent someone from being able to turn us in. One of the guys had been turned in for "venting" a system that had a bad leak. Had 10lbs static pressure left in it shouldnt have issue, but the company still got fined for it. So in my mind at least, why tempt fate?

 

[Vintage Engine Repairs]

Seals typically fail on vacuum more often than pressure.

 

[Okie]

IMHO: (and you asked)
That procedure is a little bit overboard.
Just using not over 5 lbs of free air (which can also be re-cycled) first and soapy water one can tell how bad a leak is and then do a vacuum while rotating the crank again using FREE air. (and using less costly test equipment and just the area between your ears as a detector and only one eye required)
AND a leak so small that it does not produce a fair amount of soap bubbles is not going to upset the running of a chainsaw where as a good freon leak detector could indicate a serious leak because chainsaw ROTATING seals are not designed to seal freon.
Also Al Gore and the going green tree huggers would not like your using Freon testing procedures.

 

[stihl86]

If you already have the gear, why not. On the other hand I wouldn`t go out and buy it all just to service chainsaws. Any pressurized gas would work, ie oxygen, co2, argon helium etc but plain compressed air is likely a cheaper route for most of us.

You don't check crank seals with pressure. It might hide a leak.
They have a tendency to lift under vac. That why its called a Vac/Press test.
Unless I misunderstood something you posted.

 

[pioneerguy600]

You totally misunderstood.

 

[stihl86]

You totally misunderstood.

What I did was quote the wrong post. Sorry.

 

[trains]

No need to recover it. I leave it in the case so if the saw freezes up I know it’s low and must have a leak. If I knew how I would insert a laughing smiling face to let everyone not into hvac that it’s a joke.

Throw in some dye just to be sure, easy to check any leaks with the light.

 

[stihl86]

Read the OP `s post first, I was responding to his question. You are not sorry,I have seen other outbursts from you and it won`t get you any points on this site.

This is considered an outburst?
You put a like, then this.

 

[gsonwg]

IMHO: (and you asked)
That procedure is a little bit overboard.
Just using not over 5 lbs of free air (which can also be re-cycled) first and soapy water one can tell how bad a leak is and then do a vacuum while rotating the crank again using FREE air. (and using less costly test equipment and just the area between your ears as a detector and only one eye required)
AND a leak so small that it does not produce a fair amount of soap bubbles is not going to upset the running of a chainsaw where as a good freon leak detector could indicate a serious leak because chainsaw ROTATING seals are not designed to seal freon.
Also Al Gore and the going green tree huggers would not like your using Freon testing procedures.

I totally agree it’s overboard for the majority of people. Just so happens I have all the stuff and it hooked up to my rig easily. I think air is the best bet for most people and probably for me in most cases. I didn’t even intend to do it that way when I started, the idea just struck me during the process. However my family has been on ”them peoples” list for generations so Al Gore already don’t like me.

 

[toadman]

I accidentally broke a saw seal with my JB vacuum pump hooked through my fieldpiece manifold... I got a phone call mid test & came back to 1100 microns!!
Normally it works great
I pressure test any HVAC system I repair or replace
with nitrogen at operating pressure, and leave for an hour while I clean up... then usually evacuate systems down to 250 microns.
At leading below 500.
After that there is either no leaks, or you failed one or both of those tests/evacuation.
Testing for leaks with freon/refrigerant detectors as a test is spotty at best, or at least I have not found a leak detector that will catch anything less than a 4oz a year leak.
Gas detectors & sonic detectors get massive leaks, probably enough for a saw, or to keep a house from exploding, but not enough as a stand alone test for a good refrigeration unit to last leak free.
even one running propane, I missed a few leaks in copper I was straight over top of, that I easily found with nitrogen & good soap bubbles.