[Spectramal]

I have a 2 year old Coleman EB17CX furnace with a heat pump installed. While running it on 'emergency' one night I started hearing lots of clicking coming from it. Turns out as soon as the thermostat clicks off, so does the fan! Then the heat strips pop all the limit switches until they time out. I switched back to the heat pump and it does it there too, just less dangerous on cool down.

I was thinking the sequencer until I noticed it does it on heat and emergency... What controls the fan on cool down? The fan relay??

 

[Houston204]

Sounds like you need a sequencer.

TIME DELAY RELAY (SEQUENCER)
Sequencer controls the sequence in which the heating elements & blowers turn on. This one has the ability to control up to 3 heating elements. The switches turn on sequentially within 110 seconds (H1-110) or turn off sequentially within 110 seconds (C1-110)

3115-3571

Compatible with the following units
3100-715 3100-718 3115-750 3115-751 3115A751 3115B750 3115B751 3118-750 3118-751 3118A751 3118B750 3118B751 3200-815 3400A816 3400A818 3400A915 3500-816 3500-818 3500-916 3500A816 3500A818 3500A916 6536B9151 7142-815 7142A815 7148-815 7148A815 7336-815 7336A815 7442-815 7455-815 7642-9151 7642-9151 EB15A EB15B EB15B EB15BX EB15C EB15CX EB15D EB17A EB17B EB17B EB17BX EB17C EB17CX EB17D EBH15A EBH17A EBH17A EHA15A EHA17A S1-7642-9151

 

[Spectramal]

I was thinking that too, until I noticed it does it on the heat pump as well. Can the sequencer operate the fan without the heat strips??

 

[old_squid]

Unless your air handler has a fan control board or other timing circuit that it uses to control the blower in HP mode there won't be a delay off when the thermostat is satisfied. The sequencer controls this delay in Emer. heat mode.

 

[beenthere]

Probably the contacts for the fan on the sequencer are bad.