How hot is too hot at the cat?

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Eman85

Minister of Fire
Oct 10, 2022
1,274
E TN
VC 0028 Encore new ceramic cat and installed a temp sensor probe in the cat chamber. How hot is too hot at the cat chamber? When I close the internal damper it will run the temp up to 1200-1600 easily. I can cut the air back and it will drop the temp and it will cruise at 800-1000.
 
1. Most new cats are "hyperactive". They'll heat up quick and high. This will settle down after a while (e.g. a cord burned). My manufacturer (different stove) says not to worry.

2. 800-1000 is fantastic. I think keeping it below 1400 or so is ideal. But for new cats, it's not bad if it gets above that, see my first point.
 
I've never had a probe or any thermometer on the cat with this stove until now. it will rise pretty quickly and I can shut the air way down and the cat temp still stays up. Overnight burn and plenty in the box cat was still up in the high 6's low 7's in the morning. After hot refill I can close the damper and cat will rise to over 1000 and then I can close air and it settles and cruises in the 800's. I'm still trying to understand what or how the secondary air is supposed to work.
 
Yes, the cat temp is not related to the air as the stove top temp would be. In fact, shutting the air can (not should) even increase the cat temp (because you create more smoke/half-burnt gases, which is "food" for the cat making the cat create more heat).

I have no experience with hybrid (secondary air + cat) stoves.
 
This stove is 35 years old and it has a secondary air flap that is controlled by a coiled bi-metallic spring and a probe into the chamber. I'm trying to understand the theory behind why it's there and how it works.
 
Someone else with experience with this stove will have to answer.

My guess is that it will close the air a bit when it gets hot.
That is how the (primary) air in my stove is also regulated.
 
I believe that is correct. When the stove cools down it is supposed to open the secondary air in an effort to abate a stall in the draft up the flue.
 
I have searched this forum and there are 2 schools of thought, one says closes other says opens. I emailed VC, they said nothing and to contact my dealer as it's challenging to describe.
 
So far I've had the cat temps spike to 1600 a couple of times. reload and fire's going good flip the damper and the cat will climb to 1200-1300 and settle. STT at 5-600 and all is good, cut the air back and it's fine for a while then cat temp spikes. When it spikes you can hear a rumble or whoosh in the secondary area of the stove. Open the air control whoosh gets louder, cut the air back almost all of the way and cat temps slowly drop at 1300 things get happy again and the stove goes back into cruise mode.