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SUPER Steam Pros


Anyone out there familiar with a Unilux - bent water tube boiler?

I have an existing customer with a brand new 12 million Btuh boiler (installed by others) he is unable to operate because he cannot keep water in it if it modulates above 15%.

The boiler has been boiled out twice in accordance with instructions. The water tests and looks clean. Start up has been tried using both treated and untreated water with the same result.  The static water level in the top drum is correct to within 1/2 inch.

The steam outlet is 8" - rising 36" above the flange to a 90 - travels horizontal 6ft then rises another 42 inches using 2-45's and carries on an additional 46 feet where it is connected to an isolation valve mated to an 8" check valve. On the outlet of the check valve the line increases in size to 12" and then dumps into a 14 inch "drop header".

Here is my thought: I am convinced the velocity out of the boiler is too great using only 8" piping. I think the riser off the boiler should have been increased to line size (12") as close to the boiler as possible.  Alternatively a drop header should have been used at the boiler.

I am interested in your thoughts and suggestions


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