3400-818 blower won't start

[DaveH]

The coils heat up but I just hear a click trying to start the blower. The blower will run fine if I use the switch on the furnace so can you point me in the right direction as to what to check or replace?
Thanks!

[Robert]

Most likely that the contacts on the sequencer that energize one element and blower motor are not holding.

The other sets are and those elements are energizing.


That would be the M1/M2 set. See if you have 120vac from M1 to ground and from M2 to ground.

If so, see if you have a 0vac reading across M1 and M2.


Do these with t-stat calling for heat after waiting 1.5 minutes.



Thanks,
Robert

[DaveH]

Thanks Robert
I get 0v at both M1 and M2 to ground.

[Robert]

Hi,


I corrected my earlier post, should have said 120vac to ground, not 240vac.


Either way though, 0vac shows you are not getting power to sequencer.


Depending on which side it cam in on, trace both sides.


One side should go to breaker.


Other side should go to element terminal.


The element side should then run through element, exit, go through limit and then to breaker.



Trace both side wires to locate interruption in power.



Also, remove wires from sequencer M1 and M2.


Tape the ends good and turn power ON. When you hear ALL clicks and other elements are energized, about 1-2 minutes time, Ohm across M1 and M2 to see if contacts closed.


If so, should get a reading to show continuity.



Be sure to look closely when testing and look for the markings M1 and M2.


One is on front of sequencer and other is on back.



You should have 120vac to each side from M1 and M2 to good ground.


When bottom terminals H1 and H2 close from 24vac signal from t-stat, M1 to M2 should close sending full 240vac to element.




Thanks,
Robert

[DaveH]

OK I re-tested and have 120 both M1 to ground and M2 to ground. M1 to M2 I have 240vac.

[Robert]

Is that with a call for heat from t-stat after 1-2 minutes ?


Do you have 24-28vac across very bottom H1 and H2 (test front to back terminals same as M1 and M2) .


You should have 24-28vac signal from t-stat with call for heat.


IF you have 24-28vac across H1/H2 and still have 240vac across M1/M2, the sequencer is bad.



Thanks,
Robert

[DaveH]

Yes with the coils red hot I have:
M1 to Ground = 120vac
M2 to Ground = 120vac
H1 to H2 = 25vac
M1 to M2 = 240vac

[Robert]

Sequencer is bad.


Sequencer # 3115-3571 @ $39.99 + $6.75 shipping .


It can be seen and ordered through Paypal from right side of page here:http://www.mobilehomerepair.com/ColemanElec.html


Or, by calling toll free after (AM CST Mon thru Fri to 1-877-263-7860

and charge to Visa or Mastercard .


Let me know if outside the U.S. for added info.




Thanks for inquiring,
Robert

[DaveH]

Thank you very much for all your help Robert!

[Robert]

You're very welcome, happy to help.



Thanks,
Robert