My Sears 5 hp ( ok: 2 hp) belt drive compressor has been leaking at
the unloader valve whenever the unit is shut of or it turns itself off
(for longer than I care to admit). I have been limping along with
this problem by manually regulating the pressure via the breaker or
using enought air to keep the unit running for extended periods. I
finaly replaced the unloader valve last night. New one leaks just as
much - after a moment of thought - duh, that is what the unloader
valve is supposed to do. Problem is that the unloader valve is
unloading the tank along with any residual pressure in the pump.
Question is: where is the air leak coming from? The reed valves in
the head (I presume there are reed valves, have not opened up a
compressor in 30 years) or a check valve between the pump and the
tank? Any been there fixed that? Thought I would ask before digging
deeper into the compressor. THanks

On 6/14/2011 7:37 AM, wrote:
My Sears 5 hp ( ok: 2 hp) belt drive compressor has been leaking at
the unloader valve whenever the unit is shut of or it turns itself off
(for longer than I care to admit). I have been limping along with
this problem by manually regulating the pressure via the breaker or
using enought air to keep the unit running for extended periods. I
finaly replaced the unloader valve last night. New one leaks just as
much - after a moment of thought - duh, that is what the unloader
valve is supposed to do. Problem is that the unloader valve is
unloading the tank along with any residual pressure in the pump.
Question is: where is the air leak coming from? The reed valves in
the head (I presume there are reed valves, have not opened up a
compressor in 30 years) or a check valve between the pump and the
tank? Any been there fixed that? Thought I would ask before digging
deeper into the compressor. THanks

Mine of the same vintage has a check valve in the tank where the pipe
from the compressor attaches, looks like a pipe fitting but is the check
valve. When it went I cut the pipe & installed a compression fitting
type inline.

MikeB

On Tue, 14 Jun 2011 08:08:59 -0400, BQ340 wrote:

On 6/14/2011 7:37 AM, wrote:
My Sears 5 hp ( ok: 2 hp) belt drive compressor has been leaking at
the unloader valve whenever the unit is shut of or it turns itself off
(for longer than I care to admit). I have been limping along with
this problem by manually regulating the pressure via the breaker or
using enought air to keep the unit running for extended periods. I
finaly replaced the unloader valve last night. New one leaks just as
much - after a moment of thought - duh, that is what the unloader
valve is supposed to do. Problem is that the unloader valve is
unloading the tank along with any residual pressure in the pump.
Question is: where is the air leak coming from? The reed valves in
the head (I presume there are reed valves, have not opened up a
compressor in 30 years) or a check valve between the pump and the
tank? Any been there fixed that? Thought I would ask before digging
deeper into the compressor. THanks

Mine of the same vintage has a check valve in the tank where the pipe
from the compressor attaches, looks like a pipe fitting but is the check
valve. When it went I cut the pipe & installed a compression fitting
type inline.


Same experience here on a 50 year old IR T-30, including the same
symptoms the OP describes. Grainger has replacement checks, though in
my case the OEM check was much easier to install, and worth the extra
cost in avoided time and aggravation.

BTW, any old check valve is not going to be a suitable replacement.

--
Ned Simmons

Mine of the same vintage has a check valve in the tank where the pipe
from the compressor attaches, looks like a pipe fitting but is the check
valve. When it went I cut the pipe & installed a compression fitting
type inline.

Same experience here on a 50 year old IR T-30, including the same
symptoms the OP describes. Grainger has replacement checks, though in
my case the OEM check was much easier to install, and worth the extra
cost in avoided time and aggravation.

BTW, any old check valve is not going to be a suitable replacement.

--
Ned Simmons- Hide quoted text -

- Show quoted text -

THanks for the replys. "BTW, any old check valve is not going to be a
suitable replacement" - are you referring to the flow rate of the
check valve or is there something else I need to pay attention to.
After reading the responses, I was planning on buying one from
McMaster (note: I have not yet looked to see if they have one w/ a
suitable flow rate).

On Jun 17, 10:34*am, wrote:
Mine of the same vintage has a check valve in the tank where the pipe
from the compressor attaches, looks like a pipe fitting but is the check
valve. When it went I cut the pipe & installed a compression fitting
type inline.

Same experience here on a 50 year old IR T-30, including the same
symptoms the OP describes. Grainger has replacement checks, though in
my case the OEM check was much easier to install, and worth the extra
cost in avoided time and aggravation.

BTW, any old check valve is not going to be a suitable replacement.

--
Ned Simmons- Hide quoted text -

- Show quoted text -

THanks for the replys. *"BTW, any old check valve is not going to be a
suitable replacement" *- are you referring to the flow rate of the
check valve or is there something else I need to pay attention to.
After reading the responses, I was planning on buying one from
McMaster (note: I have not yet looked to see if they have one w/ a
suitable flow rate).- Hide quoted text -

- Show quoted text -

See the ones on this page:
http://www.surpluscenter.com/pages/Catalog284-096.pdf

Usually have a bleed-off fitting on the compressor side to run to the
pressure switch for unloading. One could be cobbled up from a regular
check valve and some fittings, but not every installation has room for
that.

Stan

On 6/17/2011 12:34 PM, wrote:

Mine of the same vintage has a check valve in the tank where the pipe
from the compressor attaches, looks like a pipe fitting but is the check
valve. When it went I cut the pipe& installed a compression fitting
type inline.

Same experience here on a 50 year old IR T-30, including the same
symptoms the OP describes. Grainger has replacement checks, though in
my case the OEM check was much easier to install, and worth the extra
cost in avoided time and aggravation.

BTW, any old check valve is not going to be a suitable replacement.

--
Ned Simmons- Hide quoted text -

- Show quoted text -

THanks for the replys. "BTW, any old check valve is not going to be a
suitable replacement" - are you referring to the flow rate of the
check valve or is there something else I need to pay attention to.
After reading the responses, I was planning on buying one from
McMaster (note: I have not yet looked to see if they have one w/ a
suitable flow rate).

Flow & heat tolerance. Try to put it as far from the compressor head as
you can, that pipe & valve get HOT. I got mine from Graingers.

MikeB

On Fri, 17 Jun 2011 14:16:06 -0400, BQ340 wrote:

On 6/17/2011 12:34 PM, wrote:

Mine of the same vintage has a check valve in the tank where the pipe
from the compressor attaches, looks like a pipe fitting but is the check
valve. When it went I cut the pipe& installed a compression fitting
type inline.

Same experience here on a 50 year old IR T-30, including the same
symptoms the OP describes. Grainger has replacement checks, though in
my case the OEM check was much easier to install, and worth the extra
cost in avoided time and aggravation.

BTW, any old check valve is not going to be a suitable replacement.

--
Ned Simmons- Hide quoted text -

- Show quoted text -

THanks for the replys. "BTW, any old check valve is not going to be a
suitable replacement" - are you referring to the flow rate of the
check valve or is there something else I need to pay attention to.
After reading the responses, I was planning on buying one from
McMaster (note: I have not yet looked to see if they have one w/ a
suitable flow rate).

Flow & heat tolerance. Try to put it as far from the compressor head as
you can, that pipe & valve get HOT. I got mine from Graingers.

MikeB
Mine is a simple brass foot valve from the plumbing department. 1"
Npt

On Fri, 17 Jun 2011 14:16:06 -0400, BQ340 wrote:

On 6/17/2011 12:34 PM, wrote:

Mine of the same vintage has a check valve in the tank where the pipe
from the compressor attaches, looks like a pipe fitting but is the check
valve. When it went I cut the pipe& installed a compression fitting
type inline.

Same experience here on a 50 year old IR T-30, including the same
symptoms the OP describes. Grainger has replacement checks, though in
my case the OEM check was much easier to install, and worth the extra
cost in avoided time and aggravation.

BTW, any old check valve is not going to be a suitable replacement.

--
Ned Simmons- Hide quoted text -

- Show quoted text -

THanks for the replys. "BTW, any old check valve is not going to be a
suitable replacement" - are you referring to the flow rate of the
check valve or is there something else I need to pay attention to.
After reading the responses, I was planning on buying one from
McMaster (note: I have not yet looked to see if they have one w/ a
suitable flow rate).

Flow & heat tolerance. Try to put it as far from the compressor head as
you can, that pipe & valve get HOT. I got mine from Graingers.

MikeB

See the bottom of Grainger p.3675 for a variety of sizes and styles.
As Mike said, note the relatively high temperature rating of these
checks.
http://www.grainger.com/Grainger/wwg...Catalog= main

--
Ned Simmons

One last kiss.

A round from a .44 Mag.

Walk away ............................

On Jun 17, 9:36*pm, Ned Simmons wrote:

See the bottom of Grainger p.3675 for a variety of sizes and styles.
As Mike said, note the relatively high temperature rating of these
checks.http://www.grainger.com/Grainger/wwg...ml?browserComp...

--
Ned Simmons-


Ned, thanks for the link. I dug out the owners manual and found the
Sears P/N (CAC-437) and stuck in the manual a receipt from the local
Sears parts service ctr (long since closed) for a replacement check
valve. So I have replaced this valve once before. WIth that
knowledge I went looking in my scrap air compressor related bin. Sure
enough, I found the old one - the bottom of the valve had broken free
or unscrewed and fell into the tank. Today when I removed the check
valve from the compressor the top of the check valve is missing!
Suddenly explains the terminal noise the compressor suddently made the
last time I was using it - I ran to the machine and shut it down but
it must have run for 30 to 45 seconds w/ the valve bit(s) in the
compresor cylinder. I have not pulled the compressor head yet to see
the damage but it looks like the tank pressure pushed the valve ball
or shuttle up the pressure line and into the head. I really can't
blame the check valve - it has been leaking back thru the release
valve for over a year - I was just too busy and learned how to work
around the issue rather than to replace it when it began to fail.