HELP, I just had the modulator replaced on my furnace and don't know if it is working right. The heat blows through the register for one min. Shuts off for one min. It has been doing this for about an hour to heat the house 3 degrees! That does not seem right to me.:mad:

Modulator? Ignition module? Blower speed-control module? Post brand & model #, if replaced by a pro, give details of work performed from service invoice.

He called it a modulator... It is a sears furnace. About 15 yrs. Old. Its Honeywell

We did not get the service invoice yet.

Is the air filter clean? If clogged, the unit may be overheating and short-cycling.

Yes, it is dirty
Don't have a filter here to replace it. Will have to get one. If I take it out, should it not short cycle? Then go get a new filter if this works?

Yes. Running the system without a filter is better than with a clogged filter. Take it out, but replace it ASAP.

<<<Lynn DUH, lol
We took the dirty filter out :) Turned heat up, to see how long the blower runs. Hmmm still short cycling... I really thought this would do the trick. :mad: I am not sure that the modulator(as he called it) was the correct part for our funace. As he had to call the boss to come put it in. I hope they come back and fix the problem. Thanks for helping though. Appreciate your time.

Good luck, and share the sequel...

I hear many people call the ignition module a modulator. The only way that could cause this is if the thermostat heat anticipator does not match the new control. If he meant something else something must be out of adjustment.

>Today, the furnace man called it the board... and it was replaced because the furnace was not coming on. It started rapid cycling after he replaced it (or maybe before, and we just did not notice it). Now, he is getting a fan control switch. And maybe another part...
Like many homeowners I would imagine, this furnace has never had regular maint. So I asked him to clean things up. You would think, that would be the first thing to do, to correct any problems. Wondering how many parts will have to be replaced, as this is a Honeywell with a serial number indicating it is from 1992. Thanks for your input ;)