Boiler question

[cedricdauchot]

Hi there,

I am looking for a steam boiler for my new brewery. I found a cheap high pressure one at an auction (150psi). Our gas fitter told us about a steam trim that will make the boiler work for the low pressure. I never heard of that before.

Has anybody done this ?

Cheers,

Cédric

[gitchegumee]

Normally the high pressure boilers will have pressure regulators on them to adjust different end uses to their required pressures. So, it would be easy to get 1 bar steam from a 10 bar boiler. Perhaps this is their "trim" solution? That term usually applied to insides of valves. Anyway, I'm fairly certain that a high pressure boiler will require a certified boiler operator on site to use it. Check with your state and local codes. I'd shy away. 15 bar is some wicked steam. And who knows what condition that boiler is in? Good luck.

[rudge75]

I usually find in these situations that your local boiler inspectors love to be brought into the loop BEFORE you install anything non-standard.

And, if your inspector is anything like mine, even though he acts like an asshole, he really does have safety and your best interests in mind.

There will be no getting around the fact that if the boiler says it's rated for high pressure, all piping and downstream uses will need to be built to that code, even if you're throttling it back somehow. That may require a specially constructed room, and as above, on site certified boiler tech at all times.

[BrewinLou]

The inspector should be fine with a HPB being used as low pressure. I have spoken with our boiler repair company at length about this issue. The biggest problem inspectors have is when you buy a boiler from out of state.

[gitchegumee]

Don't know the exact plan for this boiler, but a HPB can't be used as a LPB without many modifications. Least of all will be the derating of the boiler as pressure is reduced to ~10% of rated pressure. Other considerations are the SRV, the safety interlocks, gauges, setpoints... All of which will have to be changed. If it's even possible to use the boiler at such a low pressure. The "better" option is to used it as a HPB, but reduce the pressure at the point of use. Then at least the boiler operates as it is designed, as is your point-of-use equipment. And rudge75 may have a valid point about downstream ratings of equipment. Or at the very least SRVs set for the lower pressure rating. You need to get a local, qualified professional involved in this. State and local codes often dictate installations and operations. Good luck!

[Woolsocks]

As I understand it, running a boiler so far below design pressure isn't real energy efficient. Better to keep the boiler and steam at a higher pressure and install a reducing station at the kettle to drop down to 15 PSI or whatever your kettle wants. This would have the added advantage that the steam pressure at your kettle would stay constant while the boiler cycles up and down.

[BrewinLou]

I also do not think it would be as efficient. I have spoke to Ware Energy about this subject. It is not that hard to do. Replacing the High and Low pressure cut offs with much lower ones, and replace the Emergency pressure relief valve with a lower pressure one. But it all depends on the model of boiler you have. I would much rather run a boiler under 15 psi than under 150 psi for personal safety reasons.