Hot water system for catering trailer - Help. Please. ANYONE!! :)

[Mick Mac]

Hi all. I'm currently taking on a project to turn an old horsebox trailer into a catering unit. To conform with hygiene regulations I need a separate hand washing sink so I'm trying to plan out as system with both cold & warm running water. The trouble I'm having is that all of the water heaters that I've found so far require huge amounts of electricity, which means that the generator I'm going to need is going massively up & price (& weight). The best I've found so far is a Redring Instant Handwash tap which provides water up to 50°C & is rated at 2.5 kW, which is still more than my two fridges, bain marie & lighting combined. Does anyone know of a way I can get warm running water whilst needing less power?

 

[bernardgreen]

https://www.eberspacher.com/products/handwash.html

 

[JohnD]

it's a catering unit? So surely you have LPG for your burger hotplate, tea urn etc?

 

[Mick Mac]

https://www.eberspacher.com/products/handwash.html

Thanks Bernard, this looks great however it seems it needs to be connected to a vehicle alternator, & so i think it'd be ideal for a catering van. My unit however is a trailer, & may often be parked up for some time with just a generator or a mains supply for power. If I only ever connect to a mains supply I'll be fine but I also want to be able to park up in some 'off the grid' places too, which is why I'm trying to keep my power usage low to reduce the size of the generator I'll need.

 

[Mick Mac]

it's a catering unit? So surely you have LPG for your burger hotplate, tea urn etc?

Hi John, yes you're correct about the LPG being used for my hot plate & tea urn. My unit isn't very big & so the space along 1 side is taken up completely by the hot plate, tea urn & bain marie. I have to position the water system on the other side, far from where my gas supply will come in, & I was unsure about whether I should have gas pipes going right around the trailer for safety reasons. It may just be because I'm very new to this & trying to avoid risks though. Also the LPG water heaters seem to all take up alot of space & require a fitted flue, which is why I've so far been looking for electric water heaters. It may well have to be a trade off between taking up additional space & adding a flue or having to buy a larger generator

 

[foxhole]

Caravan water heaters, very low wattage by comparison https://www.propexheatsource.co.uk/heaters/10l-water-heater

 

[bernardgreen]

it seems it needs to be connected to a vehicle alternator,

Eberspacher recommend that it is powered only when the vehicle engine is running to reduce the risk of the vehicle battery being run down and then unable to start the vehicle.

Provided the battery used for the heater is not essential to the vehicle starting and is not supplying safety critical equipment then the heater can be run from a battery.

Voltage sensing and auto disconnect to prevent deep discharge of the battery would be sensible to avoid damage to the battery.

 

[Mick Mac]

Eberspacher recommend that it is powered only when the vehicle engine is running to reduce the risk of the vehicle battery being run down and then unable to start the vehicle.

Provided the battery used for the heater is not essential to the vehicle starting and is not supplying safety critical equipment then the heater can be run from a battery.

Voltage sensing and auto disconnect to prevent deep discharge of the battery would be sensible to avoid damage to the battery.

Thanks Bernard, I'll look into this in a bit more depth. As mentioned I'm very new to this so please forgive the odd stupid question if it comes up. If my trailer was parked up at an event for a number of days, without being connected to a vehicle at all, would it rule out using a stand alone vehicle battery as it would soon run flat?

 

[Mick Mac]

Caravan water heaters, very low wattage by comparison https://www.propexheatsource.co.uk/heaters/10l-water-heater

Thanks for this, it may be just what I'm looking for as it's less than half the energy requirement of the 2.5 kW tap I'd found. I've tried calling the supplier for a chat but they're closed until Monday, fingers crossed it'll be suitable for what I need.

 

[bernardgreen]

Assume a 12 volt battery with 90 Amp Hour capacity then the heater could run ( actually heating water and drawing 10 amps ) for about 8 hours before the battery would need a re-charge. How long the heater would have to run would depend on how much water was used and how well the heated water tank was thermally insulated previngtin heat loss when not using water.

A project many years ago used a catalystic heater ( no flame ) using bottled gas to heat water in a mobile first aid unit. I can't promise anything but I still have contact details for one of the team and he may recall the supplier.

 

[Mick Mac]

Assume a 12 volt battery with 90 Amp Hour capacity then the heater could run ( actually heating water and drawing 10 amps ) for about 8 hours before the battery would need a re-charge. How long the heater would have to run would depend on how much water was used and how well the heated water tank was thermally insulated previngtin heat loss when not using water.

A project many years ago used a catalystic heater ( no flame ) using bottled gas to heat water in a mobile first aid unit. I can't promise anything but I still have contact details for one of the team and he may recall the supplier.

That would be great if you could find out the supplier Bernard. Many thanks

 

[bernardgreen]

I spoke to him last night. He cannot recall the supplier but did recall that the burner had been adapted from a bulk heater to be a "on demand" heater. The need to electrically pre-heat the catalyst made it unsuitable for user friendly "on demand" use.

 

[mattylad]

How about pass some copper (or stainless steel) water pipes through the bottom of the bain marie and feed the water through them, this will preheat the water or if slow enough heat it up and then you will need less power to make it hot.