Dishwashers ...

[Arfa Daily]

Anyone on here know anything about commercial dishwasher installations ? Need someone that understands the plumbing / electrical requirements to answer a couple of questions.

Arfa

[zaax]

Some of them are 3 phase / 330V and therefore are not DIY able

[Ed Sirett]

They are esssentially no different to install that domestic units except for then following:

1) They have a warm-up time which can be lengthy if not fed from mains hot and connected to a substantial electric supply. 2) They tend to use every little bit of the 600x600x860 cube of space allocated to them. So service pipes and wires need careful planning. 3) They cost 10x as much. 4) Once prepared they take a smaller amount of load than a domestic unit but they do it all in 5 mins, again and again.

With a cold feed and a 13A single phase supply they can take an hour to prepare themselves. With a hot feed and a 25A single phase supply they can take about 10 minutes.

Doubtless there are 3 phase supply models but I doubt they are a much bigger load than the 25A 1ph unit.

HTH

[Owain]

Agreed. And

(5) They often need external water softening within controlled/agreed limits or the manufacturer's warranty may be voided.

Owain

[Ron Lowe]

Hmmph, waranty, waranty.

At work, we recently had coffee vending machines installed. These have outboard water filters ( supplied ).

At the point of installation, we had a cold supply with a standard 3/4 BSP 'washing machine' tap. This was used to fill the old ( preferable ) tea urn, via a standard 'washing machine' hose: 3/4 BSP at either end.

The jobsworth who arrived to install the machines pronounced that he couldn't install them. They required a bare 15mm pipe stub, onto which they would fit their own hose. The other end of the hose ( onto the filter and vending machine ) was a standard 3/4 BSP fitting.

Says me: Why couldn't they just use the existing hose ( 3/4 BSP either side ) from the previous boiler?

Oh, no. Using 'another' hose would 'invalidate the warranty'.

What utter bollocks. Of course it wouldn't, unless in some way it materially affected the installation, which it clearly wouldn't.

I had to modify the plumbing arangements to suit the jobsworth. He had to come back a week later.

Utter bollocks.

[damduck-egg]

What material was your washing machine hose made of? Hoses for coffee machines and drink dispensers should made from a food quality material . I have tasted many a cup of coffee from an installation where at some point the hose has been altered with a non food quality type and the plastizers leach into the water. It is an unmistakable taste once you learn what it is,many people just think it just a bad coffee and live with it. Similar to the taste that tea and milk in a flask sometimes gets. Often found in Caravans and small boats as well as the owners use an ordinary cheap garden hose to fill the tanks rather than spend out more for a potable water one.

As for the installer they would not know the history of an existing hose, May have been used to drain the office aquarium or a blocked toilet for all they know. So they will use their own rather than risk making people ill. Also did your 'washing machine tap' incorporate non return valves? Most beverage equipment has to be supplied via non return valves and an isolation valve in case of malfunction and for service. The easiest way is to have a 15mm spur on which the vending companies own type can be fitted easily. Not fart around fitting them to your hose and rely on an unknown stop valve to work.

G.Harman

[damduck-egg]

I have come across a type that were a different style entirely. Crockery was stacked in trays designed to fit the washer and depending on the shape and size of the items there could be a couple or more trays on top of each other. The bottom of the washer would be at normal countertop height so no stooping to load. The casing then lowers from above to surround the trays and wash commences. The operation was stacks of trays on one side, a stack was slid into place on the washer ,casing lowered wash cycle done tray of clean crocks slid out other side to dry then store. very fast cycles but using very hot water from an external source.

G.harman

[dennis]

6: The last one I used needed an external detergent dispenser too. Liquid detergent and softener were feed in via a pair of pumps and a controller in the cupboard next to the washer.

[Pete Verdon]

I assumed that was the norm. Both kitchens I washed up in as a teenager had them, and the ships I occasionally sail on have something very similar.

Pete

[Andrew Gabriel]

The one in my university hall was a bit like that, and we used to use it when we ran discos to keep washing up the glasses. It was a continuous process though, with a line of trays being drawn through on a slow moving belt.

[damduck-egg]

It was mainly on ships that I came across them. Sometimes called hood dishwashers. Picking one manufacturer by googling I see that theirs can have its own boiler has a 22 Litres tank, 3 wash cycle settings

90 seconds, 120 seconds, 240 seconds. Power requirement nearly 10kW . Intended for use on a 3 phase supply.

Cruise ships often have to conform to United States Port Health requirements. The USPH inspection can leave grown men quaking as it so vigorous. The hood type of washer is a lot easier to keep clean than a cabinet type.

G.Harman

[Arfa Daily]

Crikey !! Lots of info there then, and thanks for all the comments - especially Ed with the 5 points. OK then. A bit more background. My wife and daughter have a busy cafe which for the last 4 years, they have run using a human dishwasher - daughter's husband at the moment. They have just bought another cafe, so he is off to run that one for them, so it seemed like a good time to think about a dishwashing machine. Trouble is that the building is old, and we are restricted to a single phase input, and cold only water feed. At a pinch, we can accommodate a separate 13A feed to the prep room where the washing up is done now.

We had a guy out to look it all over, but he wanted to completely redesign the whole area at a TTP price.

I have done a bit of research on these beasts, and it seems that single phase 240v 2.8kW for a 13A feed is quite normal, or a configurable option if the machine is fundamentally 415v 3 phase. I have been looking at a Maidaid D510 (a 600 x 600 x 800 'under counter' unit) which is being offered second hand at a good price. It is configurable for three power levels, 2.8kW being the lowest. It claims cycle times of 60, 120 and 180 seconds, so first question is, do these three times reference the three input power levels? So if I feed it with the 2.8kW 13A configuration, am I going to get a 3 minute cycle time ? Next question is what is all this about warm up and preparation times ? I thought that these things hotted up the water pretty much on the fly, or am I wrong there ? Do they have a hot water storage tank in them ? It wouldn't be a problem if it took an hour to warm up in the first place.

I'm ok with the water softener unit. The machine I have been looking at has one with it.

Finally, what are the requirements for the exhaust water ? Do they just discharge into an open-vented standpipe like a domestic dishwasher or washing machine, or do they have some other system ?

Lots more questions there then. Looking forward to some more good answers. d;~}

TIA all

Arfa

[dennis]

No, they are how long the wash cycle lasts.

They have a tank in the sump. They pump hot water around to do the wash and then use a little fresh water to do the rinse from another smaller tank. They pump out a bit of the old water each time.

The less power you have the longer between washes as it only has the wash time to preheat the rinse water if its busy.

Detergent dispenser?

Stand pipe should be OK. They don't empty much per cycle, but you need to empty and clean them at least daily.

[Arfa Daily]

You can tell that I'm new to this ! I don't know anything about detergent dispensers ... I assumed (wrongly obviously!!) that as detergent was needed, it would have a 'once a day' or something hopper for it if a powder, or perhaps a little suction pipe to go into a gallon container if it was liquid. Doh !

Understood on the sump tank for the hot water. So presumably, this holds enough water for a couple of cycles, given that the demand is small ? From what you say then, it seems that all three cycle times are still available, irrespective of the input power that it is configured for. So 1, 2 and 3 minute for light, medium and heavy soiling ? Do these three cycle times use corresponding amounts of water from the pre-heated tankful, meaning that if you are able to run one minute cycle times, you would be able to run almost continuously ?

I don't think that we would actually need to. It can get very busy during the lunch service, but I would still think that you could get away with running it perhaps once every 10 minutes, if you keep a good rotation of 'stock' plates and cups etc, going. Thanks for your input. All useful stuff. Appreciated.

Arfa

[dennis]

Some may have a dispenser but some don't.

The cycles use the same amount of water on the machines I have seen.

[Ed Sirett]

Agreed, although, the Winterhalter units I have installed had integral units.

[Ed Sirett]

On the machines I've installed and used even the 13A unit was able to keep up the supply of wash cycles. This would have been with a usage of say 10 cycles in about 30-40 minutes. Although you can load and empty the trays away from the machine so the between cycle time is fairly small. Nevertheless the trays are very hot and 30 seconds to 1 minute is realistically needed to exchange trays. There are other types.

[Pete Verdon]

[...]

Ah, well, these aren't cruise ships but square-rigged sail training vessels:

. The dishwasher (actually, I believe it's technically a sanitiser as it heats up but doesn't really wash - everything gets washed by hand before it goes in) has multiple trays that get passed through it but it's front-loading with a flip-down door rather than a descending hood.

I think the choice of sanitiser rather than dishwasher is because it uses less water - or possibly just to ensure that there's lots of character-building washing-up to be done :-)

Pete

[damduck-egg]

You've lost a mast since I went on one of them about 20 years ago.

ISTR the W Churchill just had two deep sinks and plenty of Hot water.

G.Harman

[Pete Verdon]

Yep, this is true, but we've gained quite a lot of climbing frame in exchange :-) If I remember rightly you only used to have one square topsail and a weird triangular topgallanty thing that I've never seen anywhere else. We've got lots to do aloft now:

Stavros (and formerly William) has two deep sinks, plenty of hot water, and the sanitiser (that leaks out the door when you're close-hauled given enough wind - not designed for sailing ships :-) ). Maybe the sanitiser is needed for those Port Regulations you mentioned? I hear they went through a phase of showing everyone a H&S video on how to wash up, but then stopped again because it was silly.

The pan bash:

Pete