[b]Permissible Motor Cycle[/b]
[b]Permissible Motor Cycle[/b]
(OP)
Hi
I am sizing a pressure tank for domestic cold water supply system in a multi-story building. I have come to the point that I need to decide what should be the maximum permissible booster pump motor cycle for a safe and long lasting operation. whould you please give me an advice or a rule of thumb in this matter?
I would like to thank all responses in advance.
I am sizing a pressure tank for domestic cold water supply system in a multi-story building. I have come to the point that I need to decide what should be the maximum permissible booster pump motor cycle for a safe and long lasting operation. whould you please give me an advice or a rule of thumb in this matter?
I would like to thank all responses in advance.





RE: [b]Permissible Motor Cycle[/b]
What size system?
PUMPDESIGNER
RE: [b]Permissible Motor Cycle[/b]
DESIN GPM=180
regards
mitcham
RE: [b]Permissible Motor Cycle[/b]
http://www.joliet-equipment.com/allowable_starts.htm
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RE: [b]Permissible Motor Cycle[/b]
We use a lot of pressure tanks, but never on your type of application. Not sure of all the reasons, but maintenance upkeep is a part of the reason if not the whole reason.
We use heat purging combined with low Ns=450-700 jockey pumps to maintain pressure at low flows, say at night. We monitor volute temperature, dump a few gallons down the drain to keep the volute cool. System is infallible and does not require any site specific information. Station ramps up and down through the flow rates smoothly, with alternating main pumps and jockey pump for the low flow areas.
If you must have a pressure tank then I hope someone on this board has a source quote for you.
If no one else helps you I have a few ideas that I hesitate to post because I have no reliable solid knowledge of using a tank in your application. My first idea would be to use the largest practical tank, then control starting frequency with a minimum run timer set so that the pump is retired by the time the volute starts to heat much. If the pump is low Ns with enclosed impeller, then that run timer can be set somewhere around five minutes.
A by-pass tube is another option to extend time before volute temperature climbs.
PUMPDESIGNER
RE: [b]Permissible Motor Cycle[/b]
The page at Well-Mate is: http://www.wellmate.com/techsupport.html
Sta-Rite recommends 1 gallon of drawdown per 1 gpm of pump capacity. Link is:http://www.berkeleypumps.com/specs/sys_fibrewound_tank_specs.pdf
I have read all their stuff before, have no confidence in it because site conditions vary so much.
PUMPDESIGNER
RE: [b]Permissible Motor Cycle[/b]
Precharge and tank location should also be considered to be sure you are able to achieve the correct acceptance volume. Most tank manufacturers have capacity curves that aid in determining acceptance volume. I hope this helps.