Air compressor headaches. - Page 2

rdm · 07-27-2003, 05:23 AM

Goood morning early birds,
We are finishing packing to leave on our summer trip here in Ontario. Yesterday I took all suggestions and spent some time trying to understand our rear air ride system and how it works.
Our coach has a Gast compressor model 2HBC-19-M220 that is driven by a 1/4 HP 29Amp Honeywell 12vdc motor.
What I have learned is the air tank leaks out overnite but the air bags stay up. I believe the air is leaking back through the compreessor because you can hear air noise when the compressor shuts off.
By adjusting the high pressure regulator with the settig screw I was able to get the compressor to shut down and not run continually. I believe the air tank has about 95-100lbs. in it when this happens (I tested it at the schrader valve)
The relief valve does not make a blow off noise at this setting so when the compressor tries to start it can't because of the load on it since the check valve on the air tank is not working it will start in 3-4 min because of the leak back. If we were travelling I do not know if it would take this long because the air bags would demand some air.
In summary I will install a new check valve at the compressor in the compartment on the line that feeds the air tank Is this OK and can I leave the original where it is.
What can I do about the blow off valve can they be cleaned or should I replace this also.
Are our high pressure settings to low
The forum help is always appreciated.
It seems I do more asking than helping.
Have a great Sunday
Ray

thenewkid64 · 07-27-2003, 05:42 AM

Ray,

I have the same basic problem. It has been reccomended to me that I place a check valve as close to the tank on the inlet from the compressor as possible. This will maintain the tank pressure and also allow for the compressor to start without back pressure due to the leaking check valve in he compressor. You will need to move the pressure switch so it is between the check valve and the tank or it will constantly cycle on an off as the air in the line bleeds off.
I think 95-100 psi is OK, but I would try to replace the pressure relief valve too. If a replacement is not possible you may want to carry some type of cap or plug in case it fails. At the least you can cap it and continue. I have no pressure relief valve on mine.

PeterH-79MH · 07-27-2003, 06:14 AM

Ray, for your situation Brett got it right:
compressor-check valve-pressure switch-tank.
This will isolate your compressor from the system pressure.
Just be aware that you may not hear the compressor for days if you have an otherwise tight system.
You indicated that your bags stay up, but the tank bleeds down.
This would mean that you have a good check valve on the bag side of the tank. Leave it there.

thenewkid64 · 07-27-2003, 06:32 AM

See Peter, I really do pay attention

rdm · 07-27-2003, 06:58 AM

Thanks Peter and Brett

On our 325 The air line schematic shows the high pressure switch reads pressure the curbside of the tank on the opposite side to where the inline check valve is. The push type coupling is also teed into this line for optional use ( I have never used it )

The inline check valve is on the line from the compressor to the driver side of the tank the check valve is connected to the air tank

Can I just install another check valve at the compressor head and leave the old one in place will this accomplish what you would like to see. At the tank as usual everything is quite rusty and looks like leave it alne

What pressure should it operate at my manual says 3lb

Do i have to move the high pressure regulator if I do this

The low pressure switch is connected to the air bags and seems to function properly.

Thanks for the help Hope to be on the road by noon tomorrow
with your help

Ray

thenewkid64 · 07-27-2003, 07:06 AM

Ray,

I think I understand, but let me be sure.

The pressure switch is mounted to the line coming out of the tank that feeds the exterior air port and the bags?

There is a check valve currently between the compressor and the tank, and that is all that is between the compressor and the tank?

If the answers to both of these questions is yes, then I think all you need to do is replace the check valve between the compressor and tank. There are check valves in some of the compressors that are used for Airbag inflation, but your setup, if I understand it right, has the addtional one right at the tank.

The reason you want the valve as close to the tank as possible is to allow the compressor some head room to start at a lower pressure than the tank pressure. This allows for an easier start and will prolong compressor life.

rdm · 07-27-2003, 07:18 AM

That is right Brett on the 325 and 345 the layout is as stated

On the opposite side of the compressor is the relief valve it has been working but does not make a sound when the compressor shuts down.

The dual levelling controls on the 325 make a need for a lot of air when driving on crowned roads as the unit is trying to right itself as you drive

Thanks again for your help
I will try to remove this valve right away

Ray

thenewkid64 · 07-27-2003, 07:44 AM

I have the dual valves as well and my system is all ways doing a dump and fill as I drive over expansion joints and in and out of parking lots.

rdm · 07-27-2003, 07:51 AM

Brett
The valve came out a lot better than expected
Is 3 lb crack pressure all right
I am off to the auto parts store for a new one
Thanks
Ray

wb13798 · 07-27-2003, 08:00 AM

sound like you need to do what is did install the check valve at the compressor and when you get the time move it to the tank . mine has been working for about a year no problems . i screwed it into the compressor head cant get any closer than that. i do plan to move it when i get around to it. lol
al

PeterH-79MH · 07-27-2003, 08:37 AM

Quote:

Originally posted by rdm
Brett
The valve came out a lot better than expected
Is 3 lb crack pressure all right
I am off to the auto parts store for a new one
Thanks
Ray

3 lb crack pressure sounds right for the 1/2" pipe size.
I would be interested to know if you found it at the local auto parts store and how much it costs?

rdm · 07-29-2003, 03:51 PM

Hi Peter and Brett
We made it out on our trip on monday.
I replaced the check valve and everything seems to work properly our first leg of our trip was 225 miles of county roads with a lot of crowning.
When I remove the old valve it was in backwards no wonder I have had problems since we bought gthe coach.
You could blow into the valve the way it was installed but with diffculty.
Peter valve was available through local UAP store but took 3 hr to delivered on Monday AM $12.50 Can about 9-10 US $ I bought 2 to have a spare.
Once again the forum help get our trip underway
Thanks Guys
Ray and Evelyn

PeterH-79MH · 07-30-2003, 05:16 AM

Ray, good deal on the successful repair.
Someone must have increased the pressure switch settings to blow thru the backwards check valve

?
Airstream dealers charge you $38.- for that valve. It's always good to uncover some of their unjust pricing.
Have a safe trip.