Emglo AirMate AM OL 78HC4V leaks air

by Keith
(Orinda, Ca)

Emglo AirMate Model: AM OL 78HC4V leaks air from pressure control box...


I have a 20 year old Emglo AirMate Oil Less 1.5 HP Dual Tank air compressor. It leaks air from the "Furnas" 125 PSI Pressure Control box. It also trips the small circuit breaker on the unit occasionally. I don't know if the two are related.

My question is: is this a safety issue? How can it be repaired? Is it worth it?

Thanks,

Keith

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Jun 11, 2017
What's wrong with it??
by: Waylon

Myimglow compressor... ( This comment seems to be about a different compressor problem. If you start a new post in this forum we will try to get you some answers about fixing your specific compressor problem. Thanks. - Moderator )

Dec 23, 2015
leak?
by: Doug in s.d.ca

The safety issue is just one of a fire hazard if the electrical safety fails. Not a problem if you don't run it unattended.

Look in the electrical section for possible causes of that problem.

The air leak is almost certainly a stuck or dirty check valve. You may be able to clean it up, or if bad comes to worse, replace it.


Good luck.

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Emglo AirMate Model #AM78 HC4V Does not shut off

by Scott
(Indianapolis, IN)

Emglo AirMate Model #AM78 HC4V

Emglo AirMate Model #AM78 HC4V

Emglo AirMate Model #AM78 HC4V
Emglo AirMate Model #AM78 HC4V Pressure switch
Emglo AirMate Model #AM78 HC4V PRV

I'm sure this has been answered before, based on your introduction that indicates there are thousands of questions and answers but I can't seem to find it (the search box above searches the WHOLE INTERNET, not just your site, so I end up with computer answers and other non-relevent stuff). So I apologize in advance!!

I have an Emglo AirMate Model #AM78 HC4V that I inherited from my Dad, so I am not real familiar with it, nor it's history. It is marked "125 PSI" on a sticker but it is not shutting off when it reaches that pressure (on what I consider the "Primary" gauge, not the adjustable one at the air supply). It continues to build pressure and then what I call the "Pop-off Valve" blows and it drops pressure immediately and I shut it off manually via the manual ON/OFF switch.

I've included a couple of photos - one of the overall compressor, plus one of what I call the "Pressure Switch" and one of the "Pop-off Valve". In the pressure switch photo - I've outlined what I call the "Pressure Switch" in GREEN. I've outlined the "Pop-Off Valve" in BLUE and what I assume is some kind of "Sensor Supply Tube" in RED, which appears to supply air pressure up to the switch so that it knows when to shut off.

We were borrowing the compressor last year for my Son's Eagle Scout project and the compressor was working fine until the "Sensor Supply Tube" split (outlined in RED in the photo), so I replaced that with similar tubing from Home Depot or auto supply store - I don't remember, but it seems to be OK now...

Then, right away when we started using it again, my current symptom started - it builds pressure in the tank, but never shuts off and then the "Pop-Off Valve" blows at about 140PSI or so.

Just providing the above regarding replacement of the tubing for background, since I don't know if these two issues are related or not??? Maybe it wasn't shutting off properly and that's why the "Sensor Supply Tube" split in the first place (too much pressure before the pop-off valve blew??) or perhaps when the tube split, it has a diaphragm or other mechanism within the pressure switch that was also damaged or needs reset or replaced???

Anyway - I'm assuming that it's the pressure switch that's not functioning now, but is there a way to repair?? Or at least test to confirm before purchasing a new one (if they're even available for this old compressor)??

Thoughts? BTW - you have a very informative site here and I can't wait to delve into it more to better understand my compressors!!

Scott

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Oct 16, 2016
Emglo AirMate Model #AM78 HC4V
by: Bill

Sorry that the search boxes didn't provide help. There used to be a toggle that could restrict the search to the site the box was on, but that seems no longer to be the case.

The pressure switch tube (red) is the unloader valve line.

The blue circle is the PRV.

Visit the sitemap page for a list of all pages on the site, and also the troubleshooting page for details about issues that trouble multi-brand air compressors, including Emglo.

Off hand I'd say that you need to open the pressure switch, and carefully (live wires) use a multi-meter to determine if power is still crossing the switch points when the tank pressure goes past a normal cut out pressure of 125 PSI. Let the compressor run to 130 PSI and then test the wires on the motor side of the switch. They should not be live. If they are, then it is likely that your pressure switch is pooched.

See the pages on pressure switches for complete details about how they work.

Buy my ebook the Home Compressor for lots more info if you wish.

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is their a replacement part (check valve) to fit a Emglo Airmate model # AM78HC4V

by Jim Elliott
(Gimli, Manitoba)

I am having a continuous leaking through the small hole at the unloader valve. I hear it may be the check valve that has gone bad. The air compressor is about 30+ years old.

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Jan 04, 2015
Check valve
by: Bill

Simply use your browser to search for Emglo Airmate model # AM78HC4V as I just did, and I found replacement check valves right away.

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AM78HC4V has air leaking out of dipstick

by Jim S
(Central Tx USA)

AM78HC4V  has air leaking out of dipstick

AM78HC4V has air leaking out of dipstick

Emglo AirMate AM78HC4V has air leaking out of dipstick bypass holes.

Compressor will not build more than 30 psi

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Nov 16, 2015
AM78HC4V has air leaking out of dipstick
by: Bill

The air leaking from the oil fill tube typically indicates badly worn piston seals.

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emglo air mate am78 hc4v noise during first cycle

by doug
(chelmsford ma)

I have an older emglo air mate am78 hc4v.its electric 4 gal. 1.5 hp. It seems to be running fine and functioning properly but it makes a very loud squealing/whistling sound when first running it for the day.

Stops after a cycle or 2.

No other symptoms not sure what the problem is...

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