Loud clacking sound on Carrier Infinity Furance during call for heat

[motoguy128]

I wonder if the gas line size is marginal (high velocity) and isn't supported well, so when it open, it hammers/vibrated. Anyone seen that happen before?

[carriercancuck]

I'm pretty sure it's not the gas valve as there is at least 20-30 seconds between that and the firing of the burners.

Is there some kind of valve connected to the inducer fan for taking in fresh air and exhausting gas? The the first part is I just can't figure out why the noise goes away for 24 hours after I turn off / on the main power supply.

I stood infront of the furnace today after engaging a heat cycle and the clunk is more like a very loud click (which is odd) which makes me think that whatever it is, is being amplified by the cold air return *argh*, but I can't figure out how or why the air intake / exhaust valve would make such a loud nosie through the cold air return.

[motoguy128]

The only other click I can thjink of is the ignitor relay, but I didnt think it was very loud.

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[carriercancuck]

The only other click I can thjink of is the ignitor relay, but I didnt think it was very loud.

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I had a visit from an authorized carrier service rep and he took at look at the unit. He noted that it was unusual and noted to me that it was a "throttle valve." It the sequence I can say for sure it starts before the igniter glows and lights the flame and I can hear a separate valve for the gas. This happens during the warm up process. I'm waiting for a call for the part to come in - has anyone has an issue with this part before?

[tiger man]

Are you turning your heating humidity down to nothing on the infinity control while you hear this noise. When you have a humidity demand, the infinity energizes the hum terminal, which in turn energizes the relay.

[carriercancuck]

Are you turning your heating humidity down to nothing on the infinity control while you hear this noise. When you have a humidity demand, the infinity energizes the hum terminal, which in turn energizes the relay.

I tried turning the humidity request all the down (even disconnected the humidifier itself) and the issue still occurred. (note I keep the humidity level at "auto" to the outdoor temperature). Granted, the clacking was there as well when I had the entry level honeywell in the house as well.