Two stage in Volume,single stage in,well,single stage. KNOWN output like a deck gun at 500GPM tip,two lengths of 2.5,at a fixed PSI like say 150. THEN you can do a FAIRLY representative comparison. Like FM says,the two pumps,by DESIGN,will be geared different. T.C.
Results 41 to 46 of 46
05-27-2010, 09:26 AM #41
05-27-2010, 11:43 AM #42
- Join Date
- Sep 2005
- So of Can. / N. of Mexico
All you have to do is read the rating plates on the pump panels.
They show the information for the NFPA Rating Tests.
1250 gpm at 150 psi test at XXX rpm.
875 gpm. at 200 psi test at xxx rpm
625 gpm at 250 psi test at xxx rpm.
It will show you the differences in rpm. I would expect the two stage to have lower rpm in the 200 and 250 psi tests. And unless there is a BIG difference in gear ratios, I would expect the two to be similar rpms in the 150 psi test with maybe the two stage being slightly higher.
05-27-2010, 04:22 PM #43
- Join Date
- May 2001
- Greensboro, NC USA
There's more to it than just reading the rating plate.
For many years, manufacturer's only offered 4 models of manifolded pumps.
- A small single stage
- A BIG single stage
- A small two stage
- A BIG two stage
Also, most two stage pumps will pass the 70%/200 psi pumping test in either pump mode, albeit one mode will require high rpms than the other. Heck, most will pass the 50%/250psi test in volume mode, but the engine will really be screaming.
Another thing to consider is if GTRider245 had any water flowing at all during the comparison. If he cracked the tankfill, or opened them completely, there's no telling how much water the pump was flowing. A 1Ĺ" tank fill will flow several hundred GPM at 200 psi. If he had them both wide open, but one has 1", and other has 1Ĺ", then it tilts the scales even further to "apples and oranges" side.
Last edited by txgp17; 05-28-2010 at 11:36 AM.The American people will never knowingly adopt Socialism. But under the name of 'liberalism' they will adopt every fragment of the Socialist program, until one day America will be a Socialist nation, without knowing how it happened. --Norman Mattoon Thomas, 6 time presidential candidate for the Socialist Party of America
05-27-2010, 06:12 PM #44
05-28-2010, 11:54 PM #45
- Join Date
- Oct 2002
Hale Auto-lube's are junk
We switched to Hale on our 92 CF Mack Servo-Command Foam pumper. We also didn't like the Waterous relief valve's prior to that. Our Hale pump's have a very high repair rate on the Auto-lube system. The seals leak water into the oiler system. It's pretty much an annual repair and cost us over $1200 per pump times two. I'd like to see us go back to Waterous.
05-29-2010, 05:09 AM #46Originally Posted by captain7
FM1I'm the one Fire and Rescue calls, when they need to be Rescued.
Originally Posted by EastKyFF
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