Furnace start up question

[Cativo]

Hi all,

A newbie to this site, but after searching around, and seeing how helpful everyone was...I figured I'd give it a shot to see if I can get some help.

Here is my issue. My folks (Elderly) had a new furnace and A/C unit installed back in 2008. The furnace is an Advanced Distributor Product Model PT6448-M175AP. Its been working great since it was installed, however, in the past month or so my dad tells me that in the morning when it first kicks on he hears a weird sound, sort of like when you start your car but the starter doesn't engage (cranking sound). Then eventually, after a minute or so this sound goes away and the furnace kicks on. I have gone over there a bunch of times, in the afternoon, and can never duplicate the issue. Both my parents swear they hear this a few times a week (So its not every time, but more frequent). My dad says he thinks the furnace is starving for gas to ignite the pilot?? At least, that's what he says it sounds like to him. The heat output is good, so its functioning fine, just this weird noise.

Has anyone ever heard of something like this? Or, anyone have any idea what this could be?

[Big]

you need a tech to come out and look at it.

[Cativo]

OK. Thanks!

[how]

There is a natural sequence of events that occur in a furnace heating cycle. The start of the inducer motor, the proving of it through a pressure switch, the start up of the igniter, the opening of the gas valve, the confirmation of that flame, the start up of the main blower. etc.
The two things will help a tech coming out for an intermitant sound issue are.

EXACTLY how long after the thermostat first calls for heat in the morning, does the noice start occuring & how long does it go on for.

Having your Dad be down there when the noice occurs to see if he can tell what part of the system he's hearing the noice from.