Fitting hand water pump in pressurised system

[Mark Thurlow]

On my Moody 49 I have a good pressurised H and C water system.

There is no manual pump and this makes me nervous of a potential nil power situation!

I plan to add a hand pump taking a feed from the pressurised hoses after a filter but before the main 12v pump using an inserted switchable diverter Y valve. So if no power switch the Y valve to the hand pump line and then manually pump.

Can you test my logic and physics. Noting getting a new pipe into a water tank directly is high on the very difficult to impossible scale.

Comments please?

[sailorchic34]

The main issue is will the manual pump generate enough head to pull water through the filter. It depends. A whale foot pump generates a max of 10 feet of head or about 4.3 psig. That's all it has. A Hand pump would be in the same ball park.

Your probably going to have at least a psi drop across the filter, if not more. It should work unless the filter has a high pressure drop. If it does not work, tie in before the filter.

[dlymn]

We have a backup foot pump which had two simple ball valves on the inlet side: one from the fresh water system and one from a through hull. By switching between these, I can pump fresh or salt water into the handbasin through an independent outlet. This covers all possibilities. Never needed to use it yet but it seems to work fine.

[bletso]

Originally Posted by dlymn

We have a backup foot pump which had two simple ball valves on the inlet side: one from the fresh water system and one from a through hull. By switching between these, I can pump fresh or salt water into the handbasin through an independent outlet. This covers all possibilities. Never needed to use it yet but it seems to work fine.

I like that idea, but in real situation I would be concerned with micro organisms from the two different eco-systems.

We have a foot pump for the salt water and a lift type pump for the fresh. (Reminds me of the old fashion well lever pumps of old. Not a good pic from before our re-model.

[Wallaby]

I draw the hand-pump water before the pressure pump with a simple T-fitting. The hand-pump is only used as a backup water supply in case the pressure system fails. I also have a second water-pump in place, which needs only the pipes switched over. Note that both hand-pump and tap water are unfiltered.

I have a separate tap for drinking water, which draws pressurized water through a carbon, and then a ceramic filter. The water is excellent, btw. This system gets very little use in comparison to 'regular' water.

[Minggat]

Minggat has 2 foot pumps with the source taken from the pressure pump suction. Non issue.
I have never figured out what the attraction is to hand pumps.
Manual pumps save water and power. My pressure system only supplies the shower now. Love the foot pumps.

I do have a separate spigot for seawater in the galley. Source is the low pressure supply pump to the RO. When valved in, I simply turn on that pump only and seawater flows freely. No flipping valves back and forth until I run the RO. Very nice to have. Also a fresh water saving device.

[Schooner Chandlery]

We have a hand pump plumbed in after the filter as you plan to do though ours is s T. It takes a good deal of pumping to get it primed but once the line is full it works dandy. It is our primary galley pump for fresh water. In our case pressure water pump is only there for a washer we have that requires pressure.

Like others, we also have seawater on its own tap in the galley.


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[Terra Nova]

Originally Posted by Wallaby

I draw the hand-pump water before the pressure pump with a simple T-fitting...

This is the correct way to plumb it. Install a separate filter, if you must.

[Mark Thurlow]

Thank you one and all - will proceed with confidence.

[adlib2]

Originally Posted by Mark Thurlow

On my Moody 49 I have a good pressurised H and C water system.

There is no manual pump and this makes me nervous of a potential nil power situation!

I plan to add a hand pump taking a feed from the pressurised hoses after a filter but before the main 12v pump using an inserted switchable diverter Y valve. So if no power switch the Y valve to the hand pump line and then manually pump.

Can you test my logic and physics. Noting getting a new pipe into a water tank directly is high on the very difficult to impossible scale.

Comments please?

I have a Whale Gusher foot pump taken from a Tee just before the Pump and works just fine, You don't need a diverter valve.

[svHyLyte]

[QUOTE=Wallaby;2044686]I draw the hand-pump water before the pressure pump with a simple T-fitting. The hand-pump is only used as a backup water supply in case the pressure system fails..../QUOTE]

We have a similar arrangement although we use a Whale Gusher Mk3 foot pump rather than a hand pump. The pump pushes (rather than pulls) water through a Slim Line Water Filter in which we use Pentek C-2, 5 Mc, filter cartridges and so can be used for drinking, if necessary. Generally, we keep the water pump shut off except while preparing meals or refilling water bottles through our Seagull IV water filter. Water to the pressure pump also passes through a Slim Line Water Filter. We find that, with the pressure pump shut off, there is far less water wasted.

FWIW...

[roverhi]

Actually hate hand pumps. Extremely hard to use if it's even moderately rough as you need one hand to hang on, one to pump and third to hold the vessel you're pumping into. Makes you want to become a Hindu. Foot pumps work way better as they keep both hands free.

Have T'd foot pump off before the pressure pump and run the galley pump through a charcoal filter to its own spigot. Will be installing another foot pump in the head and will try it T'd to the pressure line. If it doesn't work will run its own line from the galley foot pump inlet T. Pumps work way better pushing liquids than sucking them so the pump will work better drawing before any potential resistance like the pressure pump.

Use the pressure pump very seldom because it's a water waster and cycles intermittently if left on which disturbs my Zen quiet on board. Have tried to find why the pump is losing pressure without success. No evidence of leaks etc. Since I so seldom use it only turn it on for specific needs. Not worth it to wast the energy to replace components, other than the pump, to find the gremlin.

[jzaraschi]

[QUOTE=Mark Thurlow;2044210]On my Moody 49 I have a good pressurised H and C water system.

There is no manual pump and this makes me nervous of a potential nil power situation!

I plan to add a hand pump taking a feed from the pressurised hoses after a filter but before the main 12v pump using an inserted switchable diverter Y valve. So if no power switch the Y valve to the hand pump line and then manually pump.

Can you test my logic and physics. Noting getting a new pipe into a water tank directly is high on the very difficult to impossible scale.

Comments please?[/QUOTE

I would suggest placing a check value between the water feed and the hand pump. If you don't you will be sucking air thru the hand pump into the pressure system possible causing it to loose prime.
Also the check value keeps water in the feed line between it and the hand pump, making easier for it to draw water.

Not knowing what type of filter you have, but I use a 3M filter system, which prefers to have the water pushed thru it it verses being "sucked thru it.

Unless you have really bad water, I would Tee in before the pump and filter.

[dlymn]

"I like that idea, but in real situation I would be concerned with micro organisms from the two different eco-systems."

I reckon that the ball valves with their nylon seals ensure no seepage into the freshwater tank from the sea but as well, we chlorinate the fresh water. The sea water source is a last resort if you need to minimise water usage and is not necessary,

[roland stockham]

One thing to watch - you either need a way to drain the line (tap next to the 'T' is fine) or be rigorous about flushing it through regularly. I will be adding one having found the hand pump get bad smelling water if left for a while.