Results 1 to 2 of 2
  1. #1
    Join Date
    Nov 2010
    Location
    Sacramento, CA
    Posts
    42
    Post Likes

    Robinair 15600 noisy and not pulling a good vacuum

    I recently bought a used 15600 without first connecting my micron gage. The motor runs, pulls a vacuum to about 900 microns or so, then the vacuum jumps up to about 1500, makes loud clicking noises, and the vacuum reading jumps all over. From what I've read, the noises may be the reed valves. I've also read we cannot buy parts, for service, have to send the units in.

    My question, it seems that the unit has a leak. When I shut the unit off after pulling a vacuum, I hear a momentary hissing sound, my other 15600 doesn't make that sound. It's like it's pulling a vacuum but there is a leak somewhere. The hissing sound lasts for only about half a second. It seems to be coming from the top of the pump area. What are the possibilities, the ISO valve? I could pull it and look at the O rings. If it is the reed valves, how can I look at them, where are they? I've read that the pump can be noisy until the vacuum gets below 1000 microns or so, but it seldom gets under 900 and never quiets down, that's why I suspect reed valves.

    I just bought the unit used, probably paid too much and don't know how much I want to put into it. I'd at least like to know what is wrong with it.

    BTW, I've done lots of searching for answers and haven't seen these questions asked.

    Jim
    Last edited by emptech; 12-29-2017 at 05:49 PM. Reason: added info

  2. #2
    Join Date
    Nov 2010
    Location
    Sacramento, CA
    Posts
    42
    Post Likes
    Thread Starter
    Additional info found. The hissing sound was coming from the gas ballast valve. I noticed that it was difficult to screw the plug in. Removing the plug, holding my finger over the hole, shutting the pump off, the hissing didn't occur. The valve, which is actually a plug, has a copper washer and a rubber washer, no matter how tight I made the valve, I couldn't stop the leak. Examining the tread, it appears to be 3/8"-16 but the threads were damaged. That thread size is very close to a metric 10mm x 1.5mm pitch, but not exactly. I contacted technical support, they gave the part number for new parts but had no idea what the threads were.

    Very carefully, I was able to clean up the threads in the housing with a tap, not leaving any debris in the hole. Tightening the valve, I can now get the vacuum down to 135 microns. I'm not happy with the rubber washer. I have a feeling this is not the right plug.

    Customer service says the replacement parts, the oil fill cap and gas ballast valve, part number 15371, sold as a set, can be purchased at any auto supply store, good luck with that, tried one down the street, special order, couldn't even give a price.

    Question, for those of you who have this pump, what does the valve look like, what kind of a seal does it have? I think somebody has replaced the valve with the wrong one. The oil cap uses an O ring, what kind of seal on the valve?

    Jim

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.