Question about Grundfos RCP-96 Recirculation Pump for Tankless Water Heaters

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3 speed Recirculation pump lost middle speed

I have a Wilo 3 speed recirculation pump for a heating system. The middle speed has quit. Wondering if it's just a simple fix, change a capacitor or something, or replace the pump. It still works on high speed.

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  • danlawrence_ Mar 24, 2009

    Thank you. I already went and pulled the control off, tested and found a burnt winding. Ironically the other pump of 2 went the day after that on all speeds and the lady at the house described an incident with a surge. I replaced them both with Grundfos.

    Thanks again.



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It sounds like you might have had a power surge and burnt the windings on the medium speed. If it is bothersome, you will need to replace either the motor or the whole pump. (not sure if replacing just the motor is an option.)

Posted on Mar 20, 2009


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1) When pump is OFF, then hot water is no longer leaving the tank.
Most recirculation systems have choice of timer for setting specific times of operation, or thermostatic operation that activates pump when sensor detects temperature less than 90 degrees

2) Condition of plumbing is suspect here because you are not receiving fully 90 degree hot water from the recirculation system.?.

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I have a laing cirulating pump thats is worhing but now making noise so i took it apart see nothing but it was hot when running so is there any thing i can do to fix before it burns out

Open following link for Re-circulation information and resources:

If the unit is getting hot, it may have already slowed and is now spiraling to it end.
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Pump runs 5 minutes and stops

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Open following link for recirculation system resources.

The recirculation can work on either the timer or the thermostat using slide switch located next to the timer dial.
First of all, look to see if dial is rotating as time passes.
Next look at position of slide switch. If switch is moved to 'timer,' then the timer controls the on-off function for pump.
Move the pins located on timer dial to control on-off times.
If the switch is moved to ON, then the thermostat controls the pump, and turns on until temperature in pipe reaches 94 or 100 degrees F approximately. I forget exact cutoff temp.

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

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