It happened again. Some of you may remember a couple years back my cat had this problem and I figured it was from some kind of thermo shock from wet wood or engaging the combustor too soon. Well the last couple years I was very careful about dry wood and giving it proper time to engage. Everything seemed fine til yesterday when I did my spring sweep and inspection. The cat is cracked just about everywhere and there is a little crumbing or broken pieces, but not too bad yet.
I gave Woodstock a call. They have been keeping notes on me since I bought the stove. I think thats good, they can help troubleshoot. How can this be, I ask? Wood moisture is 20% or less and I always give 10-20 minutes before engaging the cat. After a good long discussion on how, what ,where, why,and when, they came to the conclusion it has to be overdrafting and recommend a pipe damper. They say my internal flue temps of 600-800 are too high and you could be sucking flames into the cat causing it to crack? What? 600-800 is the normal range for my internal probe, I thought cracking was from thermo shock, but they say flame impingement also causes cracking.
I don't know, I'm a little puzzled and upset. Chimney is 25' from top of the stove, outside wall brick chimney with 5.5" stainless liner. Wouldn't one think if I'm overdrafting I'd be close to overfiring too. Not so, I've been over 700 only a couple times and brought it back down quickly. The stove always seems under control and I don't have a roaring stream of flame going up into the cat. Since the cat is waranteed for 3 years, they are sending a new cat free of charge again, and I'm going to install the pipe damper for next season and see what happens. I wonder how many time they will let me go on this til they charge me for replacement. If it were me on the other end, I'd be thinking this guys burning wet wood and overfiring his stove. They seem to have great patience.
I gave Woodstock a call. They have been keeping notes on me since I bought the stove. I think thats good, they can help troubleshoot. How can this be, I ask? Wood moisture is 20% or less and I always give 10-20 minutes before engaging the cat. After a good long discussion on how, what ,where, why,and when, they came to the conclusion it has to be overdrafting and recommend a pipe damper. They say my internal flue temps of 600-800 are too high and you could be sucking flames into the cat causing it to crack? What? 600-800 is the normal range for my internal probe, I thought cracking was from thermo shock, but they say flame impingement also causes cracking.
I don't know, I'm a little puzzled and upset. Chimney is 25' from top of the stove, outside wall brick chimney with 5.5" stainless liner. Wouldn't one think if I'm overdrafting I'd be close to overfiring too. Not so, I've been over 700 only a couple times and brought it back down quickly. The stove always seems under control and I don't have a roaring stream of flame going up into the cat. Since the cat is waranteed for 3 years, they are sending a new cat free of charge again, and I'm going to install the pipe damper for next season and see what happens. I wonder how many time they will let me go on this til they charge me for replacement. If it were me on the other end, I'd be thinking this guys burning wet wood and overfiring his stove. They seem to have great patience.