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GVD-6 flue damper motor ‘buzzing’

cjmaria
cjmaria Member Posts: 1
in Gas Heating

WM CG-6a boiler just replaced BoilerMate (again) and had follow up issues with wiring the new Indirex device. However when connected with TT (24v) power from the boiler and the outputs of the Indirex electronic box to TT of RS 832a relay causes the motor of the GV-6 flue damper to BUZZ.

Ok - so far I’ve replaced relay and just replaced the motor control of the GVD-6.

Indirex calls for heat by closing the TT contacts of the relay and the GVD motor starts buzzing (with damper open) . Boiler never fires although signals yo GVD input and relay output to pumps is working fine..,. just no boiler .

Thank you so much in advance- can follow up with better explanation- just wanted to get it all down

Comments

  • mattmia2
    mattmia2 Member Posts: 14,136

    check voltages. buzzing is usually a bad connection somewhere although i suppose it could be whatever is connected to the end switch on the vent damper is shorted too.

  • Big Ed_4
    Big Ed_4 Member Posts: 3,260

    Any error codes ?

    There was an error rendering this rich post.

  • HVACNUT
    HVACNUT Member Posts: 6,991

    Is there a seperate connection for DHW in the CGa?

    Is the "indirect electronic box" just a 2 wire control, or does it need constant 24 volt power? What is the model of the indirect control.

    If the indirect control is just a 2 wire, that goes to TT on the RA832A. XX in the RA832A goes to the DHW or thermostat connection in the boiler.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,038
    edited September 11

    The BUZZing can be a sign of a problem, or the Humming can be nothing at all.   The transformer and the relay coils are all operating at 60 Hertz.  That means that the electricity is changing directions in the coil winding wires 60 times every second.  That is resulting in the electro magnets, that are all part of the transformer coils and relay coils, getting the message and then getting the opposite message and back to the original message faster than any woman on earth can change her mind.  If this happens with just the right amount of tension on those electro magnets, there can be a harmonic resonance that is amplified by the surrounding components. It is close to the sound of the musical note B-flat.  This noise, although annoying, can be normal and nothing is wrong with the way things are wired. 

    If on the other hand, if the BUZZing is much louder and is happening at a different frequency than 60 Hertz, you could have a wiring problem that is causing a direct short circuit when the call for operation happens.  That short circuit will cause the relay to disengage at once.  When the relay disengages, the short circuit is gone and the relay then pulls in again to cause a short circuit again.  This BUZZ will be louder and more offensive like getting the wrong answer on a TV Game show.  

    So you need to better describe the Buzz that you are hearing, and then decide if there is a problem or the mild 60 Hertz Humm of the electrical current.  If you can lightly hold your hand on the part that is Humming and the noise goes away, it is probably the 60 cycle per second hummm and not the Short Circuit BUZZ 

    Why did it just start when the new item was replaced and it never did it before? you might ask.  There can be two reasons.  The Humm is happening because there are different components operating on the same transformer as before and the harmonics just happen to sync up with the damper motor parts to cause the Humm OR the wiring is wrong causing the BUZZ

    Now I hope this makes everything clear as mud.

    Mr. Ed

       

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,038

    Looking further into your query, I know what a WM CG-6 boiler is and a CGa-6 boiler is. The CG-6a boiler might be a typo with transposed characters, so I'm not sure of the exact boiler you have, however both have a control transformer. WM part No. 381-356-578 on the CGa boilers and WM part No. 510-312-166 on the CG boilers. both are 40 VA transformers. The GVD-6 is a 6" automatic vent damper made by field controls today but may have been made by Effikal before it was purchased by Field controls. The Indirex® may be referring to an indirect water heater that is made by Amtrol. it is equipped with an electronic aquastat that requires 24 VAC to power the circuit board, and has a set of dry contacts to operate the burner/circulator/zone valve/boiler control to send the heated boiler water to the indirect tank to heat the potable water in the tank.

    Screenshot 2025-09-11 at 10.27.39 AM.png

    This electronic control requires a minimum of three 24 VAC control wires but is easier to understand it there are 4 thermostat wires. Two wires to provide 24 VAC to the control and two wires to operate the boiler zone.

    When replacing a standard two wire analog aquastat with the new electronic aquastat, there is often times the ability to cross connect the 24 VAC input wires that will cause the Humming noise. Often reversing the wires from the transformer to the aquastat 24VAC Input will reduce or eliminate the Humming noise.

    I hope this helps.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

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