New pump operator has some questions
I am on a vol. dept that has a variety of different pumpers. We have no hydrants and run tanker shuttles for water. I am normally not called on as a pump operator, but have done it at traings and have run pumpers at fill sites. I am going to take driver/operator class in the fall, but am just wondering the steps needed to "set up" the pump. I realize that different nozzles, discharges, fire loads, etc. can change but am looking for the basics. I guess this is what I've come up with from reading on here and my own experience, feel free to make corrections.
Once on scene:
1. Put pump in gear, open tank to pump.
2. Charge desired handlines based on predetermined friction loss.
3. Set relief valve
4. Once tankers are on scene, switch to drop tank (usually off front suction), close tank to pump
5. Refill tank
I had some questions based on the steps above.
-First, I read on here when flowing multiple lines to run the pdp 10 psi over the highest required dishcarge, and throttle back the smaller pressure requirements. I understand that when running 10psi over, you can see if a line is open or not. Is this a good practice to follow?
-Secondly, What is the correct relief valve setting, do you set it a certain amount over the pdp, or is there a rule of thumb for this? Usually I don't think we really adjust them, but there is rare occasions where we would use hydrants, and I was wondering how that would effect relief valve setup?
I also understand that on hydrants you don't want less than 20psi, and there is a percentage rule on how many discharges based off of pressure difference between residual and static.
-Another question, we have a lot of TFT automatic nozzles that have 50-350gpm flow rates. Most of our trucks don't have flow meters, and the ones that do are discharges plumbed into the foam system. I think I read on here that most guys figure on max flow and set the discharge pressure to that?
Lastly, do you guys usually leave a the tank fill/recirc, or some discharge cracked open in case of nozzles/discharges all shut off?
Thanks in advance, I'm sure there will be more questions to come