coal stoker boiler plumbing

leonz

Would you mind humoring me here for a few minutes??


This coal stoker boiler was installed by a non licenced plumber and 2 steel compression tanks were ripped out of the ceiling joists and an expansion tank installed.
The previous coal stoker boiler was an Axeman Anderson 260S with a 4 inch hot water riser and two 2 inch returns to the boiler sump.

The pictures are not all that good in showing everything.

The other thing thing is there is an oil boiler tied into the system and the owner does not know if it is an in series piping set up with a check valve or parallel. he said the oil boiler is heating the 3 of the 7 zones and working fine- I have yet to see the oil boiler pictures to see what the plumbing looks like.

The other thing is thing is this place is 7,000 square feet over three floors I believe he said.

The circulators location and the reduced piping size coming out of the sump gave me a primary clue and then learning about the steel compression tanks being ripped out was another, BUT I just found the "spirovent" in the system sitting on top of the compression tank.


The compression tank should be at least an AMTROL SX160V I think.


Thanks much,



Leon

hot_rod

Amtrol and Wessel have online sizers. You need some idea of the fluid volume to get an accurate size. Or if you knew the size of the former compression tank.

Unless there are tankless coils in the boilers, parallel piping helps keep the fired boiler from warming the unfired one. So a portion of the heat goes out the flue of the unfired one.

leonz

Hello Bob,

What is sticking on this for me is the rack of circulators and how they are plumbed, the feeder line from the boiler sump was reduced one size and extended to the existing header and then it was connected to the larger header with the smaller copper line.

The previous coal stoker had either a 4 inch or five inch top tapping and two 2" inch return tapping's.


They made no effort to use a larger NPT pipe to sweat fitting, larger sweat to sweat elbow then copper pipe to the existing header with a pipe to sweat adapter and copper pipe sized to the existing header.

If all six operational circulators are running at once and pulling water through that reducer bushing to the header pipe on the suction side all I can see is cavitation occurring and no little to no hot water being moved to the upper floors and the radiators.

Mad Dog_2

Blue Grunfos.....cool 😎"   mad dog 🐕 

leonz

Hello Matt, Bob, and all,

I am waiting on more pictures from the property owner:

Not stewing about this but in my over 3 decades of dealing with hydraulics in mining equipment it irks me because the property owner has no useable heat and obviously little water flowing to his radiators on all three floors of this 7,000 sq. ft. home.

As the installer who is not a licensed plumber did not pipe off the top of the steam chest with an equal or larger piping size to flood the header at the lower elevation that bothers me as it violates proper hydraulic design and the ability to pump away and reduce air bubbles to a bare minimum was not done.

This coal stoker is simular in design to both a Losch coal stoker and Van Wert coal stoker boiler with water tubes in the firebox above the Tuyere/burn pot in addition to the water volume in the steam chest.

I am sure the circulators are starved of water flow and cavitating because there is no flooded suction to the header pipe and the 2 missing steel compression tanks which were replaced by an expansion tank placed in the wrong location with what appears to be an expansion tank mounted spirovent.

I would enjoy hearing your valuable opinions.

The 3 images of the wiring spaghettti mess is something I did not want to upload

hot_rod

This looks odd, did they pipe into the boiler drain connection? 3/4"

Add up at least 6 circs that I see. Assume 8 gpm per zone circ , with 1" piping connected to them?

6x8= 48 gpm potentially flowing through that reduced piping.

leonz

I knew I was right Bob!!!!!!!!!!!!!!!!!!!
That boiler drain was installed by the fellow that installed the boiler.
What little water is being sucked through that pipe to the header must be bouncing around like Whamo superballs.

hot_rod

Are the circs pumping into the boiler, or away from? I would think that is a return header.

Either way, that is how you could do a cavitation demo.

leonz

I think your right Bob,

the other header over the boiler has 7 Bell and Gossett Flow checks so the circulators are pushing water into the coal stoker and then through the upper header pipe and through the flow checks to the radiators on the three floors.

From what I can see the top tapping has been reduced as well so the copper pipe feeding water to the header pipe feeding water through the flow checks is smaller as well. They ripped out the 2 steel compression tanks in the ceiling joists and that only makes it worse.

Edited by me 1:18 PM

hot_rod

When a row of pumps are connected to a header like that the header needs to supply the necessary gpm at low velocity, as a best practice..

If for example, if 48 gpm is moving when all those pumps are running that header should be 3" across the entire length.

But you don't know for sure how many gpm in each circuit? Could be some are moving 12 gpm, or maybe 2 gpm, who knows.

This is where a strap on ultrasonic flowmeter can be a helpful troubleshooting tool.