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Discuss Circulating Pump Replacement in the Central Heating Forum area at

  1. trusty

    trusty New Member

    Hi everyone,

    Well...with my luck, my circulating pump has crapped out leaving us freezing!

    Id really appreciate some help choosing a replacement.

    I have a 2 bed flat with electric Trianco boiler and closed Y plan system.

    Ive bled the system and while spinning the shaft/bleed screw the motor doesn't even try to move - it just hums.

    The existing pump warranty expired 08. The pump is labelled Ikon, it seems to be an old Myson pump with a bleed knob rather than screw.

    My confusion comes from the label, there is no direction arrow and the speed settings seem to be much higher than any replacements. It was set on the highest speed aswell.

    Existing settings: 0.45A -> 104W -> 1850 n(min-1)

    The replacements seem to be energy friendly types which don't show flow rate, only power, which seems to be max 44W. Am I missing something?

    To be honest Id prefer the cheapest one which will get the job done as funds are tight.

    Again, really appreciate any advice/info you can share, have a nice warm Sunday!
  2. steadyon

    steadyon Active Member

    If it hums and gets hot but doesn't rotate on its own, but does rotate if you spin it with a screwdriver, the chances are the capacitor has gone.

    Isolate all electrics, remove cover plate for electrics of pump and see if there is a capacitor inside. Usual a tube shape, about 50mm long and 20mm diameter with two wires coming out of one end. If you can read the capacitance (in microfarads) and the voltage rating you can probably get a replacement from Maplin (if still trading) or RS. Make sure you get the same capacitance (or within 20%, they are not critical) and the same or higher voltage rating. Capacitor must be OK to use on AC mains voltage. Electrolytic capacitors won't do. If you can't read the capacitance, go for 5 to 8 microfarads. If you can't read the voltage rating, go for 400V ac (NOT 230V).

    Make a note of how the old wires are connected and replace like for like. If you can't disconnect the old wires, you'll need to cut them and join to the new. Use heat shrink tubing to insulate a soldered connection, its unlikely you'll get any mechanical connection inside the cover plate.
  3. trusty

    trusty New Member

    Hi @steadyon@steadyon thanks for your quick reply.

    Will give the capacitor a check. As the pump case heats more than the water but the motor hasn't seized. And get the burnt electrical smell.

    Although, It won't even try to spin when helped along which put me off the capacitor and the pump is pretty knackered looking.
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Any chance of a pic ?
  5. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    10 year old change it , if you have a local “gas spares” shop try find a non erp compliant pump ( old ones) the likes of a 15/50 grunfoss would be fine
  6. trusty

    trusty New Member

    Existing one looks very similar to this but with different power/rate.

    If I hang off until tomorrow I can get this one which seems right.

    But could I use something like this?

    Thanks again everyone,

    ...away to check voltage, capacitor, arrow and take picture.
    Last edited: Mar 11, 2018
  7. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Either will be fine
  8. trusty

    trusty New Member

    apologies but can you explain a bit more about the differences in power/flow rate, if you have time?

    I'm guessing it has something to do with erp/non-erp eu compliance?

    It's just my existing pump has 3 speeds, it was set on the highest:
    0.45A - 104W - 1850 n(min-1)

    Which seems a lot higher than the more modern equivalents. However these only show power/current not flow rate. Are they just more efficient?

    So, if using the modern versions and if they have a lower flow rate, do I risk problems with the boiler - overheating, etc?
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Yea more efficient and same pumping head all 6m so you will be fine
  10. trusty

    trusty New Member

    with regards to the flow direction (I want Left to Right), how do I know which is correct - clock-wise?
  11. trusty

    trusty New Member

    The existing pump

  12. Gasmk1

    Gasmk1 GSR

    there will be an arrown on the side of the body pointing the direction of flow
    • Agree Agree x 1
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