Fresh water pump, 12V 3.8 GPM 10 PSI...not enough?

The pump looks fairly new, I took it apart to make sure everything was OK, looks good. Problem is if you turn on any water faucet, initially the pressure is great but after a few seconds it goes to a trickle. I hear the pump cycling but it just does not keep up and build pressure.....normal? Need more GPM? More PSI? Water tank not properly vented? go back to salt water in a bucket?
thanks,
Rob

It would help to know the make and arrangement of the pump in question. Do you employ a pressure tank? Where in elevation is the pump located and the vertical distance to the faucet or outlet? When you say the pump is "cycling" does that mean it is running then shutting down then running again, ...? or just constant running? Are there any valves on the suction side of the pump (including check valves) are there any on the outlet side of the pump?

Do you have an accumulator in your pressure water system? Have you checked your strainer and inlet line for restrictions?

FlyWright said:

Have you checked your strainer and inlet line for restrictions?

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Mine was acting a bit erratically on Friday...ONE of the maintenance items I hadn't gotten to was to clean that strainer. It was pretty funked up. Glad I wasn't drinking the tank water! Everything working fine now!

I have a 4 gph and it works very well. If the pump is sound you have a restriction. Check the screen, have a filter? Tank full? Valve open? Check valves are a problem, pull the top of any and check for function. Vent line to tank plugged? How big is your tank? Try running with filler open?

Xsbank: If you have a 4 gph as you stated you have very low expectations for a marine water system.

OK, more info. Pump is ITT jabsco model 30**-0012 (can't read numbers) Just a small demand type pump. Plumbing (less than 1/2 inch) looks to be new. Pump just seems small
I'm actually real familiar with pumps probably run 10 or more back home but this boat stuff is all new. I just wanted to make sure the way mine is working was not normal rather my wife was wondering what a shower would be like :lol:

TYPO! I guess I meant 4 GPM. All to do with not waiting for my second coffee... Then again, it's an iPad so maybe it did it all by itself. Then again, I suck at plumbing...

Xsbank: What a difference a "M" makes rather than an "H".
Roguewaver: Still not enough information but some assumptions can be made: It would to be a retro-fit pump since ITT (Xylem) took over Jabsco just a few years ago. If the original system had a pressure/accumulator tank that has not been disconnected from the fresh water system that may be your problem. The accumulator tank has been known to really upset these "on demand" style pumps. Secondly the 10 psi provided in your first post is troublesome you might verify that. Typically a "fresh water pump" will be rated at 30-50 psi. 10 psi seems more like a shower drain pump. If it is 10 psi it will pump water to a height of 23 feet ONLY. With a loss of pressure and amount of water along the way. For instance a shower head 15 feet above pump level you may only get 3 psi and maybe only 1 gpm. The above recommendation of checking the inflow strainer may help.

Researching ITT/Jabsco pump series the 3000 series is a small pump puppy not designed for fresh water systems but rather a small portable bilge type pump. Someone may have wired it as a cheap replacement with a pressure switch. That may be your problem.

roguewave said:

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roguewave said:

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Trying to post a couple pics from the TF App

Based on symptoms, could definitely be a clogged vent issue.

Par Max 4 is a freshwater variable speed pump and it appears the pressure switch is for 40 psi not 10. It must be an older series I could not find anything close to that model number listed. It should perform much better than it is. Could be the pressure switch, accumaltor tank, inflow filter (just out of view on one of your pics.) looks like it is in the engine room, if so disconnect the discharge line and turn pump on and see if it runs like a garden hose, the pump should ramp up in speed then maintain at least a 3.5 gallon flow at that point. Is the lighter in the pic. for hot water? It might be undersized.

ulysses said:

Par Max 4 is a freshwater variable speed pump and it appears the pressure switch is for 40 psi not 10. ( the switch you see says 40psi but the pump label says 10 psi)It must be an older series I could not find anything close to that model number listed. It should perform much better than it is. Could be the pressure switch, accumaltor tank, inflow filter (just out of view on one of your pics.) looks like it is in the engine room, if so disconnect the discharge line and turn pump on and see if it runs like a garden hose, the pump should ramp up in speed then maintain at least a 3.5 gallon flow at that point. Is the lighter in the pic ( just for size reference). for hot water? It might be undersized.

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Question is what to replace it with? I will do all of the suggestions y'all made first...

Is this it?

http://www.depcopump.com/datasheets/jabsco/30621-Series.pdf

http://www.pumpagents.com/pdf/JabscoPumps/30621-0012.pdf

If you have good pressure that slows to a trickle, then pressure isn't the problem nor is the pressure switch as the pump built up to desired pressure and shutoff before you opened the faucet. Some where in your system is a flow restriction. With the faucet open and the water trickling, if the pump is cycling on and off, then the restriction is after the pump. If the pump isn't cycling while the water is trickling, the restriction is before the pump. You could still have a pump problem, but I'm thinking there is a restriction after the pump.

Ted

So I really start crawling around and tracing lines (thought I'd found em all) and what do I find hidden away, a secondary filter (10 inch), it looked dirty so I removed it.....problem solved!
Thanks yall for helping, much appreciated

Water pressure, Nice

If that filter was dirty, then it's been collecting debris from the water. Maybe it's needed.

Now that the filter's out, it might be helpful to remove the faucet screens and shower head and flush the system real well from each outlet for several minutes to rinse out any dislodged debris or mineral deposits.

Glad you found the blockage.

Yes I'll find a few replacement carbon/sediment filters and put one back in. Sure glad I found the problem, just could not figure out the why.

roguewave said:

Yes I'll find a few replacement carbon/sediment filters and put one back in. Sure glad I found the problem, just could not figure out the why.

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That's one of the great things about this forum. We have so many experienced folks who are active in the TF community, have seen this before and are very willing to help.

So very true!

FlyWright said:

That's one of the great things about this forum. We have so many experienced folks who are active in the TF community, have seen this before and are very willing to help.

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