Fresh Water Pressure Loss

[pjop]

I have a Jabsco 3.5 GPH pump and recently the water pressure drops dramatically within the first few seconds of use. I attempted to find an answer using the google CF search and can't find one on point. I do not have an accumulator tank but the pump is not cycling unless a faucet is used. Can I assume that the diaphram in the pump is shot and I need a new one? I just find it odd that I have great pressure for the first few seconds. If the pump was bad why would I initially have good pressure?

If I would have know that I would be living aboard I would have gone to trade school instead of law school. Thanks a bunch for any assistance for what is probably a pretty stupid question.

[svcambria]

It could be a restriction in the line that brings water to the pump - junk in the line or a filter plugged. It could also be that the microswitch on the pump has a low pressure setting for turning the pump on so you get a prolonged time of low pressure. Does the pressure while running water recover after the drop?

Michael

[bstreep]

I'd guess a restriction. A restriction would allow pressure to build up, yet not yield much flow.

[GordMay]

Originally Posted by bstreep

I'd guess a restriction. A restriction would allow pressure to build up, yet not yield much flow.

As Bill suggests, a restriction in the pipe between the pump & faucet, would allow pressure to build behind the restriction. This would prompt the pressure switch to keep the pump off, until faucet opened, dropping pressure. When faucet opened, the pump would deliver a reduced quantity of water past the restriction, at a reduced pressure. Pressure would be high in fromnt of restriction, but low after.

[pjop]

Thanks all. Sure enough a water restriction. I totally forgot about the water filter previoius owner installed between the pump and the tank. I've owned her a little over a year and haven't really messed with the fresh water system since previous owner had installed a new water tank, lines and evidently a big giant Surflo filter. My girlfriend said "honey, couldn't it be a filter" and I said there wasn't a filter. I am ashamed to admit that it wasn't until y'all answered that I remember the filter system. So, thanks for your help with the fix and, of course, I learned more than one thing. I try to refrain from calling her "the admiral" but, if this keeps up, she'll promote quickly up the ranks.

[Chief Engineer]

Another place to check...is the little aerator that may be on the end of the faucet....In a marine environment they seem to clog with fine sand like particles.