Coleman 3400-815 not getting very hot if at all.

[CaptDunsel]

Greetings,

You guys have always given me very good information on this site and have helped me diagnose and replace a bad sequencer and fan motor in this unit before and I can not tell you how much I have appreciated that help.

With the mild winter we have been having down here in Chattanooga I have not been having to use my central heat very much. I have two oil filled radiant type heaters that have done a good job most of the winter for me and seem to be more economical that the central heater. I set that to 68 so it only cuts in when the little heaters can't handle the load.

That being said I have noticed on a few recent cold nights that the central heat cuts on but only seems to blow cold air and never seems to bring the temperature up much if at all. It looks like it just runs continuously until the sun comes up and it warms up enough outside for my little heaters to finally bring the temperature back up.

Could I have a bad heating element or some bad relay/sequencers, etc.? Could you offer me some advice on how to determine the problem? I work on X-Ray equipment for a living so I am not squeamish about poking around inside live equipment with a voltmeter.

[DaleM]

First you can check to see if the sequencer is sending power to the elements. Should have 220v or so when testing at each end of the element, do not read through the limits. If so, then pull power, disconnect the wiring from the elements and see if you have continuity through them. Strange as it sounds I believe all your elements are cooked. Since you have been using auxillary heating in your place you may have never noticed the loss of 1 or 2 elements. Now maybe the last one has gone and the furnace is simply going through the motions but not heating.

[CaptDunsel]

Thanks Dale,

I removed power and took off the front cover and A quick visual inspection found the problems. 1) 1 yellow wire from fuse to sequencer burned through. 2) Red wire from double pole sequencer to center element connected to coil connection of sequencer instead of the opposing pole of the contact that the red wire from the fuses went to (Glad that one didn't cause any issues!) I connected the red wire to the correct contact and went to ACE hardware and got a foot of 10 gauge copper wire (had it in yellow no less) and two high temperature crimp spade connectors and replaced the burnt wire. Powered everything up and eureka, we have heat! Seems to work a lot better with three elements instead of one. guess that could explain the nearly $500 heat bill for December!

Thanks again, you guys are the best.

Kirk

[DaleM]

Glad you're all fixed up!!