Question on PSG's theory here...

[usernametaken]

Today it was supposed to get up over 50 so knowing this, I shut down the furnace last night and switched to LP. This morning I did my first heat exchanger and stove pipe cleaning of the season. My wood is super dry this year so other than the super light powdery stuff that a good sneeze will remove, it looked pretty good. After cleaning the upper chamber and pipe, I cleaned out the firebox. When I was done I noticed the small ash had filled in cracks in the bottom 3 fire bricks that have the holes in them for the rear lower air supply. Once vacuumed out, I could see that cracks had grown beyond hairlines so I decided it was time to get some new ones. Now, here's the question. Why would PSG use vermiculite for these three bricks? Real fire brick isn't hard to drill so my only guess is that the cold air coming in through the air supply behind them would crack hot fire bricks due to the extreme temp difference? That's me totally spitballing as I really can't imagine why they would use that material there. Worse yet, those three "bricks" get more abuse than any others in the firebox from loading and raking coals. I can imagine that they will have to be changed yearly if they stay vermiculite. My other option is to buy standard firebricks and drill them. Thoughts? I'm going to call PSG tomorrow and ask them what their reasoning is here but thought maybe you all might have some thoughts as well....

Pic of the offending weak links:

 

[brenndatomu]

No idea why the different material...but those cracks wouldn't bother me much...as long as the bricks stay in place, shouldn't affect anything really....but if I were to do something about it...my first choice would be to repair...take them out and glue the pieces together with furnace cement...which I have done with standard firebrick, and the baffles too...it works great!
But if they crumble too much upon removal, I personally wouldn't hesitate to replace with standard firebrick.
Might want to lay off the "50 yard pass" split loading procedure...

 

[usernametaken]

I hadn't thought about cementing them back together. Perhaps I'll do that for now but they are pretty bad when removed with chunks falling out. I just didn't want them crumbling further with the weight of the top bricks sitting on them. I don't think it's the loading that really got them as bad as they are. I was using a fireplace poker last year instead of the supplied right angle poker and I likely impaled them more than once... Oops...

 

[brenndatomu]

I likely impaled them more than once... Oops...

 

[usernametaken]

Well, I was almost cursing you sir. I just went down and pulled everything apart on the back wall and was afraid it was too bad to go back together. However, I was able to clean everything up, dampen it, and load it with high temp mortar that I happened to have on hand. (It was open since last year at this time so I was glad to see it hadn't gone bad...) Anyways, it ain't pretty but it's all back together and likely a lot stronger than it was before. I'll still call to see why PSG used ceramic board there and if they say no real reason, I'll swap them to drilled firebrick in the spring. I think this will get me through this year if I'm careful though... Thanks again for the advice on the mortar!

PS: Now that I have that sorted for the time being, I'll have to figure out a better way to keep those holes ash free. Perhaps a quick use of the ash vac once in a while. They were totally plugged when I did my cleaning today which must have been affecting my burn.

 

[brenndatomu]

Anyways, it ain't pretty but it's all back together and likely a lot stronger than it was before.

Whew, glad it worked out and I'm not in the doghouse!
Make sure you give it 24 hours to dry before firing up...at least that's what the stuff I've used said to do...

 

[usernametaken]

Mine says it needs heat to cure. Says low fire for the first hour then full blast up to 500 or more to finish the cure... Good to 2k after that.

 

[laynes69]

I've had furnaces with cracked firebrick for years. Doesn't hurt a thing. I just learned not to throw wood into the firebox.

 

[usernametaken]

If these were made of firebrick, I don't think they would have even cracked. Making them out of ceramic board just doesn't make sense to me. They are going to get damaged no matter how gentle you are being such a soft material.

 

[usernametaken]

Well, I just placed a call. The guy taking calls could give no reasoning as to why those three bricks are not actually bricks but did tell me that if I changed them to drilled real brick that I could void my warranty. Not quite the info or explanation I was hoping for.

 

[andym]

Well, I just placed a call. The guy taking calls could give no reasoning as to why those three bricks are not actually bricks but did tell me that if I changed them to drilled real brick that I could void my warranty. Not quite the info or explanation I was hoping for.

Tell him that's ok. Just send me a free replacement every year.

 

[usernametaken]

I was thinking of something like that but decided to just agree and get off the phone. They want $15 bucks each for those three "bricks" plus shipping. I'm looking for a piece of board that I could cut and drill myself but not much out there in 1.25" thick. The stuff I found so far isn't much of a better deal either. It just kills me to spend $15 each on these things. I can get a box of 6 Rutland fire bricks for $31 delivered from Amazon and cut and drill 3 of them to match and have 3 leftover. They would last longer and save me coin. I'm just not sure if there is actually a reason they didn't do this from the factory? Based on the call today, I guess I'll never know.

 

[sloeffle]

I was thinking of something like that but decided to just agree and get off the phone. They want $15 bucks each for those three "bricks" plus shipping. I'm looking for a piece of board that I could cut and drill myself but not much out there in 1.25" thick. The stuff I found so far isn't much of a better deal either. It just kills me to spend $15 each on these things. I can get a box of 6 Rutland fire bricks for $31 delivered from Amazon and cut and drill 3 of them to match and have 3 leftover. They would last longer and save me coin. I'm just not sure if there is actually a reason they didn't do this from the factory? Based on the call today, I guess I'll never know.

What a rip off, I'd love to know the profit margin on those bricks. Maybe @SBI_Nick knows why they use different brick.

 

[SBI_Nick]

What a rip off, I'd love to know the profit margin on those bricks. Maybe @SBI_Nick knows why they use different brick.

I'm not the one who has design the Max Caddy, but i believe it was a manufacturing decision. You can leave it there even if they are cracked, as long as they protect the firebox it is fine. By the way, you can use a standard firebrick, cut it and drill it to the same size (very important to have the same dimension) and it will work fine.

thanks,

 

[usernametaken]

Thanks Nick! I suspected that was the case but the gentleman who answered the phone wasn't the warmest fellow and offered little other than a warranty concern. Anyways, I have my answer and my solution now and I really appreciate you dropping in to my thread to clarify...

 

[jmcmahon4]

Anybody got the measurements for where the holes go in the 3 lower bricks in the back.
I just realized when I replaced them a couple years winters ago I didn’t drill holes in them. PSG website wants $25/brick but they’re out of stock

 

[usernametaken]

I used my old one as a template. I would try using cardboard to make yourself a template since you don't have any of your old ones. Those holes are very important and I think you'll see a difference in your burns once you get them back to where they should be.

 

[jmcmahon4]

Thanks for the template idea, I’ll try that today unless someone else knows.. I was just hoping to have them all ready to do a quick swap. I’m not sure how I missed that when I changed them the first time
And yeah hopefully my burns are better after this

 

[usernametaken]

There are air inlets behind each of those holes so I'm sure you'll get a more even burn after drilling...

 

[jmcmahon4]

Yep.. burns are way better now. Can’t believe I did that

 

[SBI_Nick]

What a rip off, I'd love to know the profit margin on those bricks. Maybe @SBI_Nick knows why they use different brick.

Hi,

first as long as they hold together i wouldn't replace them. That doesn't affect the performance or the safety of the furnace. I believe it is a production reason why it's a different material.

Thanks,

Nicolas