Is it Necessary to Depressurize a Boiler Before Shutting Down for a Couple of Hours

"Shutting down" doesn't give you a clue?

1. Boiler Shut Down
2. Boiler Shutdown, - Banks Engineering Inc

Probably not. Boilers regularly start and stop under automatic control, without depressurizing each time they stop.

Not with this sort of boiler:

In fact, if one shuts it down, it depressurises all on its own.

Depends, for what you are going to despressurize the Boiler?

boiler is supplying steam to a bread production line. When there is off production period like 5 hours out of 24 hrs in a day, the boiler will have its steam pressure holding,after switch off. Can we use it when production resumes back. Or shall we have to depressurise,blowdown and start back after off period when production resumes again. My question is regarding the condensation of steam after switch off the boiler.

It shouldn't matter. If it does, then there's something wrong.

Blowdown should be based upon boiler total dissolved solids [TDS] measurements. Many low pressure boilers blow down at 3000ppm TDS.

No it is not necessary to "depressurize" a boiler between uses in fact if you can keep pressure on the boiler it is better for it because when you take pressure off the boiler, oxygen gets into it causing pitting and corosion. The boiler will naturally lose pressure as it cools and when it gets down to 5 psi or so you should vent it to prevent it from going negative.

Dear Mr.georgerin72.

The answer is NO, not necessarily to be de-pressurised, as long as safety is not blowing, and completely fire is put out.

DHAYANANDHAN.S