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[ScottP]

I had to replace the air flow door control solenoid about 3 months ago as it was bad. Fitted the new one and everything was fine. This morning however, the control fuse for the solenoid had blown and so no air flow and no heat. I replaced the fuse but it popped as soon as I turned power back on. I disconnected the wires to the solenoid and replaced the fuse again. All good until I reconnected the wires and the fuse popped again. What would cause the new solenoid to go bad in 3 months. Seems they should last longer.

[RSI]

Is the door stuck? Are you using the same type fuse?

[ScottP]

I can open and close the air door by hand, no resistance. The last solenoid I replaced was jammed and wouldn't move. I replaced the fuse with the same one as before. I was going to take the solenoid back tomorrow and see if they will replace it.

[Scott7m]

Do you have any power issues or power surges in your area?

I have no idea why but there is one valley near me and about once a year every stove owner in that valley has there solenoids go bad all at once.  Then last year during the tornado outbreak I had a lot of people call for solenoids when they turned power back on in and around west liberty.  I am not sure why they are or seem to be sensitive

[snakedriver]

Hi Scott,

Sorry to hear of your troubles.

Not sure if you have or would be comfortable using one, but a simple measurement of the solenoid with an ohm meter while disconnected from the furnace will reveal volumes. It will reveal if the solenoid is indeed shorted and should be replaced, or whether the problem lies upstream from the solenoid. The reading of the solenoid should be low but not zero. Zero resistance blows fuses. The sizing of the fuse is such that only the solenoid should get power through it.

If there is an intermittent action taking place or a dead short elsewhere, the fuse will blow even if the solenoid is still good.

Talk to a friend or neighbor who is an electronics technician and can use a VOM (volt, ohm, milliammeter). It will be a simple matter for him or her to diagnose your problem. I just would hate to see the solenoid get replaced and still have the problem. Also lubricate it per the manual with WD-40.

Best of luck.

Jerry

[Scott7m]

I'd use something longer lasting than wd, but excellent advise

Wd-40 evaporates fast, we can soak engines in wd-40, let them dry for a week and paint them with no bubbles or fish eyes, meaning it's all gone.

[johnybcold]

My 1400 kept popping fuses, the solinoids goes because the PC board is not sending the correct current test the board, I ended up with a new display

[ScottP]

I borrowed a tester just now and get a zero reading, so I guess its fried. Just not impressed as it was new 3 months ago.

[Ohiowood]

What are you oiling ? With wd40 oil motor oil

[johnybcold]

I will have to check the ZcB manual my unit is going on 2 seasons I never lub anythink, can you check the volts going to the solinoids? I think there is a thread on here that mentions what the wires should be

[zimmer988]

When we build control systems and we always install a transient voltage filter on the outputs of our PLC's to protect the solenoids and PLC contacts. When inductive loads such as solenoids are de-energized it can produce damaging transient voltages.  Try something similar to this wired in parallel with your solenoid:
http://catalog.rke.com/item/transient-voltage-filters-suppressors-/le-phase-120-vac-240-vac-transient-voltage-filters/rcs?