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I could have been wrong on the NPSH. But still we have to prevent the suction side to go into negative pressure.

This is because the expansion tank is regulating the pressure of the system. Based on my previous example if the pump head still remain as 30psi and the expansion tank charging pressure is changed to 20psig and is installed at the discharge side of the pump. The discharge pressure is now at...

I was told by my senior that in a closed loop system, pressure never change at the point the expansion tank is installed. This is because the function of the expansion tank is to regulate the pressure in the system. The expansion tank can be installed at the suction or the discharge side of the...

I was thinking with the reduced pressure for the pressure tank, I could have reduced the tank volume capacity too. The original tank sizing is as follow: 1. Chilled water temperature is 44degF (take 40degF and SV1@40degF = 0.01602 Max ambient temperature is 104degF (take 100degF and...

Thanks LittleInch for the advice and I have attached the drawing now. The building is still in construction and will be commissioned in 2 months time. The expansion tank is not yet installed, in fact it is not yet purchased. The hydromaxi pump room is beside the main chilled water pipe riser...

Thank you for all your replies. 1. There is an air vent at the highest point which I have added 5psi to it. 2. The floor to floor height is GF 8MH, 9F 5.5MH and the rest 4MH. I have marked it out in my revised attached drawing. I also indicate the static pressure on the drawing. 3. There is no...

The simple schematic for the chilled water hydronic piping and the main domestic cold water piping is attached.http://files.engineering.com/getfile.aspx?folder=6b712a9d-f264-4ac9-af89-1f48a20a5e21&file=Aircon_Water_Pressure1.pdf

I am working on the Chilled water Hydronic Piping System of a 10-story office building. The Chiller Plant Room is at the Ground Floor. The bladder type expansion tank is installed at the suction side of the Chilled Water Pump inside the Chiller Plant Room and the water pressure at the bladder...

I am just wondering if I direct a make-up water pipe to the equalizing line instead of to the individual cooling towers, this would this minimize the stagnant water problem.

Thanks Mr Drazen for your advise. I will do my sizing based on the selected Fan Coil Capacity.

The Design Manual for Heating, Ventilation, Plumbing and Air Conditioning Systems by Lee Kenderick maybe is what you are looking for.

Thank you Mr Drazen for your reply. This issue was came out when I was doing my chilled water pipe sizing and Balancing & Control valves selection for a Kitchen cum Dining Room. The space has a Sensible cooling load of 6.7RT and Latent load of 3.5RT (Total Cooling Load is 10.2RT, SHF is 0.66.)...

My friend was talking to me that the chilled water flow rate design should base on the Sensible cooling load only instead of the Total cooling load (Sensible + Latent). The control valve selection would also follow the Sensible cooling load only. His reasoning was that if there is no humidity...

Thank Waramanga for sharing.

I would like to know if we could reduce power loss by filtering the electrical harmonics and thus have energy saving?

I also think that all these are scam. However, there is another guy trying to sell this energy saving device which work only on discharge lamp. What he claimed is that the normal discharge lamp only need the full voltage of 230Vac at starting. After the fluorescent lamps are lighted up for 15...

The makeup expansion tank is fed by the same pressurized bypass water system through a float valve. What I am saying is that the expansion tank in turn feed the aircon chilled water system through gravity.

A guy try to sell me an energy saving device which work by cleaning or rather filtering out all the electrical noise and harmonics. He claims that the device can save electrical bill by 8% to 20% depending on the existing power quality and improve the life of the electrical installation...

Yes, it is confirmed that the damages all related to the network components. Now the carparking system is up and running again.

As per what VEiBLL said, the AC power system is fed through indoor transformer (stepdown 11kv/415v.) The recent case of lightning strike, beside the 3 NIC, on of the network repeater/router switch also gone. We are now in process to get quote for fiber optic link.