Steam Boiler Venting

Cyclone33

I have a Crown BS1172NFZZPSU propane steam boiler.

Input 172k btu/hr
Output 142k btu/hr

I was considering installing a liner in my chimney. It is about 30' high and my boiler is about 5' over horizontal. Based on the tables, i believe i would need a 4" type B vent if i line my chimney. Other option would be to have my chimney cleaned and inspected. Which is a better option? Can i put a chimney cap on for either option? Thanks in advance!

leonz

Being a novice;

Is the chimney height 3 feet taller than the highest roof on your home?

When was the boilers burner cleaned last and the mud flushed out of the sump? Was the pigtail cleaned and the pressuretrol checked for accuracy?

Do you have the proper venting on the end of the basement header pipes and your radiators?

If your chimney has a clay flue tile liner you should not need a chimney cap one unless you have issues with down drafts and your home is surrounded with tall trees.

Cyclone33

Hi @leonz ,

They chimney is over 3ft higher than highest roof point.

Boiler burner is cleaned yearly. Has not been flushed recently - do you have a recommended process for this?

I have a vaporstat that was new last year. Accuracy checked.

There are 4 gorton #2 vents on the main. 2 pipe steam trane vapor system so no vents on radiators.

I will have to confirm the flue liner.

Thanks!

ChrisJ

@Bob Harper

Jamie Hall

Your chimney will have to be cleaned and inspected before you put a liner in, so do that first. Then think about a liner if the chimney has problems — but I doubt you'll need one.

I'm not sure what the problem is?

Cyclone33

I was told I should have a liner so thats why i was asking.

I will get it inspected to confirm condition. If it is in good shape, is there any reason for a chimney cap?

thanks

Jamie Hall

Screen at the top, absolutely. Cap? Kind of optional.

delcrossv

https://forum.heatinghelp.com/discussion/comment/1813678#Comment_1813678

One of the buildings I service has no screen. I have to remember to take a plastic grocery bag with me every fall to remove the inevitable dead bird.

Bob Harper

The chimney should have a level II inspection, which, if properly done, will indicate a ss liner sized to the appliance. I've never found a sweep who has found a masonry chimney lined with TC tile that meets the code, much less that has held up for any length of service. Keep in mind tiles are 2ft long. They have joints. Those joints are laid in Portland cement-based mortars, usually a type N. The code calls for a medium duty non-water soluble calcium aluminate refractory cement mixture. Never seen it in the wild. The liner will also size the flue to the boiler. Use a smoothwall ss liner so you don't have to derate it 20% for corrugations.
Listed liners require a rain cap. Spark arrestor screens are optional and limited in opening size so they neither clog easily nor allow birds in. Bats and bugs can get through. Sweep the liner into the room with a broad radius at the base- no tee. Not needed and adds flow resistance. With 2-3" of liner into the room, attach an appliance connector for the transition to single walled unlisted pipe. I use rigid ss chimney liner as connector for a permanent connection. I incorporate a slip section for easy disassembly allowing inspection or service and re-assembly.

HTH