High pressure steam moves faster than low pressure steam....

delta T

Proven scientifically too.....

This. This is why this site is so important.

https://www.youtube.com/watch?v=GUZoW_AFujM

STEAM DOCTOR

Scary how many people take this garbage seriously. Look at the comments on his video. Sad.

brandonf

This is scary.

DanHolohan

He has made several videos. I’ve written to him and offered to help him understand. He has never responded. He says on some of the videos that he’s too busy to answer anyone.

KC_Jones

I commented and invited him here a while ago, also pointed out the flaw in his test method. He apparently has plenty of time to delete comments....

AnthraciteEnergetics

Didn't watch the video but this is an issue that is sometimes treated as a religious dogma with no thought or if it even matters at all.

Higher pressure difference can push more volume per minute through a pipe, meaning higher velocity. The rate at which steam moves is flow rate / cross sectional area of pipe, and if the pipe is cold and condensing some of the steam.

Low pressure steam is less dense and takes up more volume, so velocity for a given mass flow rate (and BTUh) is higher.

A system at equilibrium (hot) with low pressure steam will have higher velocities for the same BTUh and pipe size compared with high pressure. This is why pipe sizes can be smaller at higher pressure differences - including vacuum.

A problem I see often is people not realizing that steam systems start off at zero pressure difference when cold. Pressuretrols and vaporstats mean nothing until the system is hot.

A pressuretrol set at 5 lbs. will behave the same on startup as one set at 0.5 lbs. It will be low pressure steam with velocity determined by firing rate, pipe size, and pipe temperature - until everything is hot, and assuming the boiler can make steam faster than the system can condense it.