Secoh air pump stopped work? Fault’s probably the easily-replaced diaphragm

The following is written entirely for the benefit of Google, and you, dear reader, who probably like me has a Secoh EL 80 15 pump or similar that has stopped working. It may have been one year or it might have been three. (That’s what happened with us.) Maybe it’s powering a cess pit or a koi carp pond or whatever.

You’re thinking you might need to buy a new one. What!! TWO HUNDRED POUNDS!!

Don’t worry. The thing that goes wrong is the rubber-ish diaphragm that vibrates back and forth to pump the air around. You can buy spare parts for these. They’re much cheaper – about 60 pounds.

If the pump is a few years old, then you should probably replace both diaphragms – they’re arranged one each side of an electromagnet in the centre of the device.

Replacement isn’t hard at all. If you have a Philips (cross-head) screwdriver and about 20 minutes to spare you can do it yourself. Try not to do what I did and crossthread one of the screws so it breaks off when you’re doing the replacement. Gah.

You also have to change the position of the centre rocker so that it’s evenly placed between the electromagnet (you’ll find it’s on one side when you open the pump up – usually over to the diaphragm that’s intact. Shift it back to the middle).

You can download the manuals for Secoh pumps. Useful.

Hope that helps.

7 thoughts on “Secoh air pump stopped work? Fault’s probably the easily-replaced diaphragm”

  1. FYI Still lots of ‘broken images’ on your blog!?
    Two in the header and two in the right hand column? (+ the RSS feed buttons etc.)

    Is it just me?

  2. “Try not to do what I did and crossthread one of the screws so it breaks off when you’re doing the replacement. Gah.”

    hehe i’ve lost count of the times i’ve done this. Usually it is on a head that someone else has tightened and it’s worn slightly leaving me the joy of finishing it off!

  3. many thanks I have a Secoh el – 200 not working two diaphrams cracked. but when you fire it up 240 the electromagnets do not work? John

  4. I HAVE IN MY 2YEARS OLD £35,000 TO BUY & INSTALL SEWAGE TREATMENT PLANT, FIVE SECOH 250 TWIN PUMPS . EACH PUMP HAS GONE WRONG ON MORE THAN ONE TIME . I DON`T REMEMBER THE LAST TIME THEY WERE ALL WORKING. AT PRESENT ONE PUMP IS BACK AT THE PLANT MAKERS BEING FIXED. ANOTHER ONE THAT CAME BACK LAST WEEK IS RUNNING VERY LOUD !!! THE PLANT SUPPLIERS FBJ IN BASINSTOKE UK TOLD ME TO TURN THAT ONE OFF THIS AFTERNOON AFTER A PHONE CALL FRON ME. IT`S NOT JUST THE DIAPHRAMS THAT ARE GOING. PARTS ARE COMING UNGLUED INSIDE THE PUMPS.
    IN MY OPINION THEY ARE TOO FRAGILE & COMPLEX FOR THIS USE. WOULD NOT RECOMEND THESE TO MY WORST ENEMY.

  5. My experience tallies with Chris’s. My Secoh EL-S-100 pump lasted three years before expiring.
    I’d replaced the diaphragms as recommended. The fault? The magnets are glued into an aluminium
    carrier that acts on the diaphragms. Both magnets had moved until jamming up the carrier.
    Net result burnt out coils. There are several references out there quoting the billions of
    operations these diaphragms cycle per year and how important it is to replace them. I’d agree,
    but as someone working in engineering design I can state categorically that it would be very easy
    to produce a design that cost much the same but would never allow the magnets to move.
    I have now replaced the pump with a unit from the competition. Its much cheaper to buy and the
    service kits include the magnets and carrier at little more than half the price of the diaphragms
    for the Secoh unit. My local installer of sewage treatment plant (I’d guess that they are probably
    they biggest in the UK) tells me that they now fit the alternative as standard.

  6. EL 60 Secoh airpump – Thanks for info – 1 of the diaphragms had split – however I stripped the lower thread on 1 side of the pump as well ! – the secret is to tease the lower part of the diaphragm holder into the locating notch first + lower screws then do up the top 2 screws.
    One thing i forgot to do was reset (central position) the blue plastic autostop switch so had to take it apart again ! Now seems to be working fine – will see how long it lasts.
    What was the make of the cheaper/better competitive pump so that I can look out for one in the future. Do you know who does the cheapest genuine replacement diaphragms – they seem to vary considerably ?
    many thanks & kind rgds
    Alan Kirk
    01788 890526

  7. My magnet failed too, turns out my pump had been getting really hot (cause of the magnet problem). Cause of pump getting hot? Blocked pipes down in my tank. Part replaced, pipework cleared and pump has worked perfectly ever since – five years later, it’s had a couple of filters and the diaphragms replaced once. Secoh stuff gets my vote, wouldn’t dream of using anything else. My problems were caused by the system .. not the pump.

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