pressure control switch

I am preparing to purchase a pressure control switch for our RV mobile feed water.
????? Are all the pressure control switches the same //ie., ones used for air compressor verses water pressure systems?
I don't want to purchase the wrong one for the job since" I need to reset the pressure setting at 45 to 50 pounds. We have a 6 gallon pressure tank capable of 60 pounds pressure and all new
"surgical plastic" lines.

Air compressors use the same theory-of-design switches but are different. What kind of water pump are you using? Not clear on the "RV" statement. Some RVs use plastic pumps with built-in regulators. Some other RVs have more conventional high pressure pumps with storage/pressure tanks and 30/50 PSI switches. If you think you need to replace a bad switch, why not just match what you have?

A little tip on those switches. You do NOT want to play with the adjustments. The springs are set for different pressures. Just buy the correct pressure at the start. Check your local RV joint or plumbing supply store.

NO they (talking RV here) are not all the same, I've had several of both in my 49 years of RV ownership. More so in in days past when an RV used a galvanized water tank (pressure rated at perhaps 60 PSI or so) a small 12 VDC 'Air Compressor" pumped air into the tank to pressurize it. HOWEVER in recent times many use a plastic/composite fresh water tank (not much more pressure rated then gravity and the water it can contain) and a 12 VDC On Demand "WATER" pump on the output to feed the RV. If ???????????? the pressure switch is bad (be it on a demand "water" pump or an "air" compressor) and ifffffffffffffffff you can find a replacement switch that's likely cheaper then a whole new pump.


I'm not quite sure what you mean when you say "RV Mobile Feed Water" so I will qualify what can only be my "best guesses"

Are you pumping "air" into a tank to force water out (like some RV's) orrrrrrrrrrr pumping "water" (home but could be used in an RV) ?????????????????????


1) When you say you have a "6 gallon pressure tank capable of 60 pounds pressure" that's not very big, but if it can indeed withstand 60 PSI that sounds more like EITHER an "air" compressor type (if an RV set up) OR even a home well "water pump" type set up that could work in an RV.

2) When you say "ones used for air compressor verses water pressure systems" not knowing exactly what you mean, again my "best guess" would be NO they are NOT. The RV's I owned that had a galvanized tank and an "air" compressor used a pressure switch on or near the "air" compressor. The home water well systems I owned on farms for like 40 years used a pressure switch that was in the "water" plumbing (where it sensed the pressure) and turned the pump on or off accordingly.


In the event all you need is a pressure switch similar to those found on home well water 120/240 VAC systems (can work in an RV if that's your set up??) those are fairly common and generic and adjustable (maybe in 20 to 60 or so PSI??) and likely have more current and voltage and pressure rating then you would need as they may be used on a 120 or 240 VAC water pump that might draw 10 to 30 or so amps. IF THATS WHAT YOUR REFERRING TO (and can work in a pressurized RV system) they are mostly basically the same type and might be rated for HP, Current, Voltage and may be one or two pole. Square D among many others make those home well water adjustable pressure switches in the 120/240 volt range and perhaps 20 to 40 amps of current, one or two pole, and some have the low pressure safety cut off feature so if pressure drops below x PSI the pump shuts off. THOSE ARE IN THE WATER WHERE THEY SENSE PRESSURE that's NOT the same as the small 12 VDV Air Compressor pumps used in some RV's

Sorry that's the best I can do from here not understanding your question so well.

John T 49 year RV owner and still a happy camper

If you have the original, get the make and model, search online for it, or one within the pressure range, made for water, with DC rated contacts suitable for the pump motor load.

Usually can save a considerable amount avoiding the RV dealers.

"Usually can save a considerable amount avoiding the RV dealers. "

AMEN to that Steve, save even more if its a Boat Marine dealer lol. If he has a 120/240 VAC 1/2 pole Water Pressure Switch like used on home water pump systems (can likely subject to ratings still work on a small 12 VDC) they are available at about any hardware or big box home stores.

John T

To Further Qualify the question. I am wanting to install a pressure switch on the feed water system in which I have a 6 gallon 60 pound capacity pressure tank [new this year] So I was attempting to figure out IF the type of pressure switch used on water pressure systems was the same or not as the ones used on an air compressor? or are they different. Also how I need to go about adjusting the switch to 45 -50 pound setting.
Thank you for your answers so far.
Wm.

If you buy a 30-50 water pump switch you can change it a little to what you want. The springs are different for different pressure settings, but they have a range, and they can be changed a little.

HI again thanks for the update. To your most recent more specific question:


"IF the type of pressure switch used on water pressure systems was the same or not as the ones used on an air compressor? or are they different"


A) If you Google WATER PUMP PRESSURE SWITCHES here are a couple results:

https://www.lowes.com/pd/Square-D-30-50-PSI-Plastic-Exterior-Pressure-Switch/3134937?cm_mmc=shp-_-c-_-prd-_-rpe-_-bing-_-lia-_-207-_-tanksandwatersupplypumps-_-3134937-_-0&kpid&store_code=1894&msclkid=c865c5918a811c7148ac981e18325ea6&gclid=CMfs7IuA9OQCFZdPgQodps4DRg&gclsrc=ds

https://www.homedepot.com/p/Square-D-Pumptrol-30-50-PSI-Well-Pump-Water-Pressure-Switch-with-Maintained-Manual-Cut-Out-Lever-FSG2J21M1CP/206398814?cm_mmc=Shopping%7CB%7CBase%7CD26P%7C26-5_PUMPS%7CNA%7CPLA%7c71700000034388192%7c58700003952496744%7c92700032054947237&msclkid=a21f0b7468fc1c57168256fbfbf9d6e1&gclid=CNLKrauA9OQCFUGGgQodjK8Lmw&gclsrc=ds


B) HOWEVER if you Google AIR COMPRESSOR PRESSURE SWITCHES here are a couple results:

https://www.homedepot.com/p/Square-D-Pumptrol-125-PSI-Air-Compressor-Pressure-Switch-FHG12J52XBP/206398804?cm_mmc=Shopping%7CB%7CBase%7CD26P%7C26-5_PUMPS%7CNA%7CPLA%7c71700000034388192%7c58700003952496744%7c92700032054947237&msclkid=22e19ddcc2f015cdb44bc0535183910b&gclid=CL_L1OCA9OQCFQ-ZgQodDo4IcA&gclsrc=ds

https://www.northerntool.com/shop/tools/product_22938_22938?cm_mmc=Bing-pla&utm_source=Bing_PLA&utm_medium=Air%20Tools%20%2B%20Compressors%20%3E%20Air%20Compressor%20Parts%20%2B%20Maintenance%20%3E%20Air%20Compressor%20Pres&utm_campaign=Square%20D&utm_content=16151&msclkid=625d2413f40411bdc7f7799c679d5bd0


BOTTOM LINE EACH DESCRIBES EITHER WATER ORRRRRRRRRRRRR AIR USE AND THEY DO NOT APPEAR THE SAME

MORAL OF THE STORY If I was going to use it for a water pump system Id use a WATER pressure switch NOT an Air Compressor Switch.

Im NOTTTTTTTTTT saying either will work or not for other use Im ONLY saying what the search indicated THEY ARE DIFFERENT


John T

If you go to a store to buy pressure switches ones for water are in one area and ones for air are in another area for a reason they only work for what they where made to work on. Air pressure switches are preset for pressures in the 80-120psi for kick on and off. Water on the other hand can have them preset for 40/50 on and off or 50/60 on off etc.

I thank each of you for your assistance in this matter. The pump that supplies the pressure system for our RV doesn't want to shut off when it reaches 45 lbs., just keeps running. Since it is supposed to I know the internal switch is not functioning properly so I will simply install a standard water system pressure switch and set it to approximately 45 lbs., rather than fight with the internal pump control. [just easier]
Have found a control from a local supplier.
Thank you again for your assistance.
Wm.

Just courious..

Most RV's have a 12 volt water pump. 99% of those pumps have a pressure switch built into them.

Most pressure switches can be bought for less than $30 for most fresh water 12 volt RV pumps.

Using a common 120 volt pressure switch you will need a Tank Tee, pressure guage and the other fittings to connect it. A new Shurflo, 3.5 gpm, 45 psi fresh water pump for around $70..

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The biggest difference between a water and air pressure swith is the air has a bleeder valve. The valve bleeds the pressure from the compressor to tank check valve so that the compressor does not start under load once the tank pressure drops enough to trip the switch.