230v water pump for a towable bar unit

[littlespark]

My mates bought a mobile bar. I’m going to be checking the electrics but I’ve got a more plumbing question.

he’s wanting a small under sink water heater, just for hand washing. There’s little chance he will get a fresh water piped supply where he sets this thing up. His idea is to get a water barrel like one for a touring caravan, but use a 230v pump instead of 12v (there is no 12v system installed)
Would any shower pump work?
Needs to pump water from the barrel for cold water, and through the heater for hot.

the electric supply is limited to the 16A commando plug, so a max 2kW water heater? When there’s 2 bottle fridges, a freezer for ice cube bags and whatever lighting he plugs in.

The other question. More a statement of fact, I’m pretty sure what the answer is going to be....
There is no consumer unit in this shed on wheels...
There are MCBs and an rcd mainswitch mounted on dinrail, inside plastic 100x 50mm trunking with the lid cut to suit.
Is this, or has it ever been, acceptable.?

 

[davesparks]

Your best bet is to look in to touring caravan equipment, they are usually on an 16A supply when they are on a caravan site so presumably have all the systems needed to provide for hot running water on a small supply.

 

[littlespark]

Thanks Dave.
I’ve got a caravan, the water pump, lights, radio and a few other things are powered from a 12v leisure battery. Only the 13A sockets are on the mains voltage (and the battery charger).

this unit doesn’t have a 12v system, or any water system. (It has sinks, with drains, but was only used as an ice bucket)
I’m just wondering if a shower or central heating pump could be used in the same way as a caravans 12v pump

 

[davesparks]

A central heating pump no as they are designed for circulating water not pumping to an outlet.

A shower pump will work, but may empty the water tank too quickly and probably go bang when the supply of water runs out.

I don't know what is normally used in catering vans, despite having seen a lot of them in my career.

 

[littlespark]

Catering vans, built for purpose, will probably use a 12v system same as a caravan.
This unit seems to have been hand built, 3 sides open up, metal supports each corner. As described in the OP, any consumer unit is non-existent. Belfast sinks used as ice buckets, and the worktops appear to be copper clad. A few old immersion tanks were harmed in the making of it.

 

[ruston]

I would also go for 12volt and caravan water barrels with a couple of leisure batteries (if necessary, maybe one) and a charger.

 

[Lucien Nunes]

Shower pumps are designed to boost the pressure of a water service that already has at least some pressure. They are normally centrifugal and therefore not self-priming i.e. they require water to be fed into their inlet ports, they will not suck it in from dry, nor will the flow switch operate unless there is already some flow. They may also be damaged if they do run dry. As per Davesparks, central heating circulators are not designed to handle fresh water, only the closed circuit of a C/H system. They will corrode and maybe turn the water rusty, and the bearings may seize, when exposed to oxygenated water. That is why secondary circulators for hot water service are more expensive; they are made of bronze instead of cast iron. These too require flooded suction and can be damaged by dry running, and probably don't deliver enough head.

Whilst there are specialised centrifugal pumps made for pressurised water systems (Stuart used to make them, amongt others) IMO they are too finicky and quirky for a small and simple setup like this. I would strongly recommend a normal multi-diaphragm RV water pump, as this will be self-priming and will lift water into itself from the tank, will be OK with dry running, and will incorporate a pressure switch. Definitely fit an accumulator tank, need not be huge, say 5l, for steady flow and longer pump / pressure switch life. If you don't want to install a battery, run it from a regulated DC PSU of perhaps 100W rating.

 

[littlespark]

Ok. Answers my question, thanks lads.

it’s add a 12v system or nothing

 

[Lister1987]

Stupid item, roof mount water storage (caravan slimline waste barrels?), Rig so you have some gravitational energy at the outlets (thinking a rig to get them from horizontal to vertical) them put your shower pump at the mouth of the barrel(s).

Gravity will provide the initial flow into the pump, boosted by the shower pump.

 

[davesparks]

Stupid item, roof mount water storage (caravan slimline waste barrels?), Rig so you have some gravitational energy at the outlets (thinking a rig to get them from horizontal to vertical) them put your shower pump at the mouth of the barrel(s).

Gravity will provide the initial flow into the pump, boosted by the shower pump.

You have to get the water up to the roof in the first place, so would need another pump to do that.
Plus of course draining and removing the rooftop tank be fire towing the trailer anywhere.

 

[littlespark]

Ok. Wandering brain time.

12v caravan water pump supplied via plug- in transformer rather than leisure battery?

 

[Scintillam]

Refrigeration cabinet condensate pumps are 230v, would need modifying to work for this use though, air con also have 230v pumps.

There’s also small pumps you can get that fit onto a drill.

 

[Lucien Nunes]

12v caravan water pump supplied via plug- in transformer rather than leisure battery?

As per my last sentence of Post #7?

We had one just like this the other day:
Another pumpy powery thing

 

[R-fur]

Plus one for going 12V just for safety, but if you must have 230V what about a pump from a washing machine?

 

[littlespark]

I don’t know how I missed what you said last sentence of #7, @Lucien Nunes.

I’ll source a 12v pump and psu and see what it can do.

 

[Lucien Nunes]

what about a pump from a washing machine?

Much too low a head, not self priming, probably won't like dry running, exposed basic insulation and moving parts... it's not very suitable. I'm not sure what the attraction is of pumps for different purposes. There's dozens of choices of product for exactly this application that will work straight off the shelf, e.g.
Various Shurflo pumps

 

[davesparks]

Refrigeration cabinet condensate pumps are 230v, would need modifying to work for this use though, air con also have 230v pumps.

There’s also small pumps you can get that fit onto a drill.

what about a pump from a washing machine?

These pumps are unlikely to be suitable for potable water and so unlikely to be safe to use in this scenario.

 

[littlespark]

Refreshing this thread. I got a self priming pump that works like a caravan one, but off a 230v socket. (Ok, it’s a 230 adaptor stepped down to 12v but it’s built for purpose)
Pressure is pretty low, but customer is happy. Been fitted a while now. He’s not been able to take it anywhere yet, he’s still working on bits and pieces....





That is a microscope.... repurposed as a draught gin delivery system.