Potable water pump location

[MrFish]

Does it matter where the potable water pump / accumulator etc are located? I had intended to fit it next to the water tank in the bow, however i am conscious of the voltage drop  by the time it gets to the bow and wondered if the could be fitted in the engine bay by the calorifier where i have plenty of room and easy access?  

[Tony Brooks]

12 minutes ago, MrFish said:

Does it matter where the potable water pump / accumulator etc are located? I had intended to fit it next to the water tank in the bow, however i am conscious of the voltage drop  by the time it gets to the bow and wondered if the could be fitted in the engine bay by the calorifier where i have plenty of room and easy access?  

 

The further it is from the tank, the more resistance to flow (under suction). Also, if you run out of water or drain down the more air it has to shift before it manages to get any water. However, When I bought my ex hire bar the water pump was under a rear bunk, say 40ft from the tank and it seemed to work OK.

 

Volt drop should not be any sort of problem as long as you specify the correct cable size of the run (out and back) length and current flow.

[matty40s]

Most Stowe Hill boats had the water pump under the kitchen sink in mid boat area.(the term reverse layout hadnt been invented then)

[Sea Dog]

15 minutes ago, Tony Brooks said:

The further it is from the tank, the more resistance to flow (under suction). Also, if you run out of water or drain down the more air it has to shift before it manages to get any water.

This ^^^^

 

My own pump is close to the tank and I still had an issue with the original pipe from tank to pump narrowing under suction as it aged. Cured by replacing it with a wire spiral reinforced hose, which isn't cheap over a long run. Whilst you could use tough plastic water pipe as the feed, it's best if the pipes either side of the pump are flexible and have a loop to help isolate noise and vibration.

[ditchcrawler]

24 minutes ago, matty40s said:

Most Stowe Hill boats had the water pump under the kitchen sink in mid boat area.(the term reverse layout hadnt been invented then)

Mine is in the galley, half way between the tank and the engine room/batteries

[cuthound]

25 minutes ago, ditchcrawler said:

Mine is in the galley, half way between the tank and the engine room/batteries

 

So are mine. The only downside is room for me when replacing a pump as there are kitchen units either side of the gangway.

[ditchcrawler]

It a cool job, my bum is in the fridge 😁

[BEngo]

21 minutes ago, ditchcrawler said:

It a cool job, my bum is in the fridge 😁

A vindaloo opportunity the previous night?

 

N

 

[David Mack]

4 hours ago, Tony Brooks said:

 

The further it is from the tank, the more resistance to flow (under suction).

But a correspondingly shorter distance (under presssure) from the pump to the taps. So overall it will make no difference to the flow (as long as the pipe between the tank and the pump is not so flexible as to collapse under the suction).

[GUMPY]

I've had pumps at the front of  boats and near the back, makes not a jot if difference.

Present pump is at the back under the bed next to the calorifier cupboard, it has a 25litre accumulator so rarely cycles when the loo is flushed at night.

[rusty69]

Our pump is at the front by the tank. The pipe goes from the tank to the pump at floor level and then from the pump up under the gunwale to feed the boat. I guess if the pump was halfway along the boat, then some of the pipework may need to be at floor level to avoid priming problems. 

Edited February 17, 2023 by rusty69

[Jen-in-Wellies]

20 minutes ago, rusty69 said:

Our pump is at the front by the tank. The pipe goes from the tank to the pump at floor level and then from the pump up under the gunwale to feed the boat. I guess if the pump was halfway along the boat, then some of the pipework may need to be at floor level to avoid priming problems. 

It is with mine. The pump is about twenty feet from the bow tank. All in 15mm Speedfit, for collapse resistance and at floor level. The bow up trim of the boat gives a good gravity assist to priming on the rare occasion the water runs out.

[rusty69]

1 minute ago, Jen-in-Wellies said:

It is with mine. The pump is about twenty feet from the bow tank. All in 15mm Speedfit, for collapse resistance and at floor level. The bow up trim of the boat gives a good gravity assist to priming on the rare occasion the water runs out.

Yes, I did wonder if the bow up position would assist with priming. I guess the tank being empty will help with this situation. 

 

If the tank is full, the pump must be much harder to prime. 🙃

[magnetman]

Worth putting pump above water tank. If I was doing a narrow boat I would build a small cupboard for it and the pipes about 1ft above top of tank to whatever side of the front doors on the inside bulkhead. 

 

Easy to replace when it wears out and any leaks mean air in the water rather than water in the boat. 

 

Soundproofing in the pump cupboard also worth considering. The accumulator can be on the floor after the pump. 

Edited February 17, 2023 by magnetman

[Jen-in-Wellies]

2 minutes ago, rusty69 said:

Yes, I did wonder if the bow up position would assist with priming. I guess the tank being empty will help with this situation. 

 

If the tank is full, the pump must be much harder to prime. 🙃

That only happened the once, when the plumbing was first installed and the pump fired up. The boat was a sailaway and the builders supplied it with tanks full. Fortunately, it only had a diesel and water tank and doesn't have a pump out tank 😝. The tank came with a speedfit isolation valve on the exit, to which I fitted the pipe to the pump. I don't recall any problems with priming, but it was a long time ago. A couple of seconds of the pump sounding unhappy, then normal noises as it filled the downstream pipes and cauliflower (open taps).

[David Mack]

9 minutes ago, magnetman said:

 

Easy to replace when it wears out and any leaks mean air in the water rather than water in the boat. 

Only in the pipework before the pump. And much more difficult to find which joint is leaking.

[ditchcrawler]

With the watertank full you probably have an extra 2 foot head of water to push it to the pump. Take the lid of the strainer and see how fast you flood the boat.

[MrFish]

So a good idea to have isolation valves either side of the pump to allow easier removal without needing to drain the system.

[ditchcrawler]

1 hour ago, MrFish said:

So a good idea to have isolation valves either side of the pump to allow easier removal without needing to drain the system.

Yes

[enigmatic]

More important: either put it above the level of the water tank, or above something that lets you know when it gets dripped on and drains somewhere other than your carpet

 

Don't ask me I know...

[magnetman]

On 17/02/2023 at 09:08, David Mack said:

Only in the pipework before the pump. And much more difficult to find which joint is leaking.

I've never had any pipework leaks but have had plenty of water pump leaks resulting in water on the floor in previous boats. It's a well known issue with pumps. They leak after a while. 

 

Why would position of pump make finding pipework leaks difficult ? 

 

I don't understand this comment. 

 

To me the basic priority is to avoid getting water in the boat. If you get too much water in a boat it stops being a boat. Best avoided. 

 

 

Edited February 20, 2023 by magnetman

[system 4-50]

I put all (nearly) of my pipwork joints & my pumps on a wall below the gunnel.  Underneath all of them I put a length of plastic guttering with a 15mm draining pipe which led into the shower.  The idea was that any leaks would drain into the shower where it would be noticed before getting severe.  It also made any maintenance easier as it was simple to drain sections before working on them.  The arrangemant I had meant that some maintenance had to be done whilst kneeling in the shower tray.  The first time I did this I was suprised when my trouser knees suddenly became wet!  Thereafter I had a detachable pipe that ducted the water straight into the shower waste hole. 

[David Mack]

2 hours ago, magnetman said:

Why would position of pump make finding pipework leaks difficult ? 

Leaks on the pressure side leak water out, and are easy to find. Leaks on the suction side suck air in and are much harder to find.

[MrFish]

Where do the leaks most commonly occur? Is it the pump itself or the pipe joins?

[magnetman]

1 hour ago, David Mack said:

Leaks on the pressure side leak water out, and are easy to find. Leaks on the suction side suck air in and are much harder to find.

Why would you need to worry about a leak which is sucking air in? 

In my experience it is usually the pump itself which leaks. If you elevate the pump above the tank then when it starts leaking you get air in the water supply rather than water in the boat. 

 

I definitely prefer air in the taps and a bit of spitting than a damp floor or worse.