Chilled water pressure

[GHAZ]

Hi guys i went into a plant room to look at a compressor and i saw the water pressure gauge and it was reading about 110 psi, and i asked the engineer if the guage was correct and was told yes . i have never come across more than 4 bar water pressure, has anybody else seen this sort of pressure on a water chiller.

[El Padre]

Hi Ghaz,

Not personally, what was the application, was it process cooling for some sort of machinery?

Cheers

[GHAZ]

It was aircon for offices

[Gary]

How tall was the system (building height)?

[Gary]

It takes 12psi to push a column of water up 28ft. It takes 120psi for a 280ft high system.

If this minimum pressure is not maintained, there will be a vacuum at the top causing all sorts of air lock problems.

Being non-scientific, I just figure out the height of the building and divide by 2. This gives me a little extra.

[Grizzly]

It takes 12psi to push a column of water up 28ft. It takes 120psi for a 280ft high system.

If this minimum pressure is not maintained, there will be a vacuum at the top causing all sorts of air lock problems.

Being non-scientific, I just figure out the height of the building and divide by 2. This gives me a little extra.

Thanks Gary
That is a useful tip!
Grizzly

[ref717]

Indeed having a 110 psi chilled water supply pressure is too high based on my experience in plant aircon chillers. What is the TDH requirement of your chilled water pipeline loop?,or better yet check the chilled water return pressure or the suction pressure of the chilled pump near the chiller,the pressure should be in the range of 20-25 psi to be able to have good chilled water recirculation as well as minimize pipeline leaks brought about by high pressure within the pipe loop.

[Tesla]

Hi GHAZ
Gary is right. I must assume the pressure was at the bottom of the building. You can get high pressure chillers for locating at the bottom of a building but they are not common.

[GHAZ]

hi its a 4 storey high building and the water pumps are in the basement

[Tesla]

Thanks GHAZ
That pressure doesn't sound out of the ordinary. Other considerations would be on a cooler day most of the chilled water valves would be shut, if installed the chilled water bypass valve may not be callibrated correctly to maintain the required system pressure differential, and most chillers would have around 20 to 60 psi press drop through the coooer, or the pump coud be oversized and the butterfly valve could be backed off to minimise cavitation.