hot water supply for my darkroom

Discussion in 'Darkroom Equipment' started by Matt5791, May 5, 2006.

  1. Matt5791

    Matt5791 Subscriber

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    Just doing a complete rebuild on my darkroom!

    I was wondering if anyone had any ideas about hot water supply. I only have the option of an electrical supply and I was looking at some of the under-sink compact heaters available.

    I figure all I need is something that will enable me to provide a supply at around 20 degrees for washing prints - so this equates to a trickle of hot water into a mixer tap with the cold.

    Does anyone have any ideas here?

    Thanks for any help.
     
  2. Bob F.

    Bob F. Member

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    I use a 3kw instant water heater designed for hand washing which has the advantage that it will connect to the normal mains supply without having to run special cables etc. I can get water at 40 degrees C at any time of year out of it in London.

    Cheers, Bob.
     
  3. Kino

    Kino Member

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    You know, I was looking at all the plumbing I did for my darkroom yesterday and bemoaning the fact that I COULD have installed a instant hot water heater, run only the cold water line (clear across my basement) AND had uniformly warm/hot water instantly rather than wait a few minutes and waste several gallons of water attempting to stabilize the temperature.

    I may yet do it just to avoid the tempering wait...

    Long story short, I would second Bob's suggestion.

    Frank W.
     
  4. Fintan

    Fintan Member

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    Hey Bob, can you give make and model of it?
     
  5. Bob F.

    Bob F. Member

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    I got mine from Screwfix but a quick check shows they no longer stock that type - the only ones they have are under-sink ones of at least 5.5kW. You can get them elsewhere however, including UK ebay (http://cgi.ebay.co.uk/SANTON-HAND-W...ryZ42234QQssPageNameZWDVWQQrdZ1QQcmdZViewItem) . That one is identical to the one I use except that I removed the nozzle on the end and fitted a flexible hose. I assume you will not have too much trouble finding something similar in Ireland.

    One point: this works by heating the water while the water flows through it. In practice this means that the temperature is dependent on the speed of the water: the slower you run it, the hotter it comes out (a safety cutout stops it getting too hot if the water flow is too low). Now in the spring, the minimum temperature coming out of the unit is around 25C. More sophisticated versions with separate temperature controls are available and would be a better bet as you would then not have to install a separate cold water tap & mixer hose as I have....

    Cheers, Bob.
     
    Last edited by a moderator: May 9, 2006
  6. aoresteen

    aoresteen Subscriber

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    You guys are lucky! In Florida & Georgia the cold water is 77 to 80 degrees and a decent chiller runs $1,200. If I ever do another darkroom I will add a seperate 30 gal water heater and a chiller.
     
  7. Jim Jones

    Jim Jones Subscriber

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    Although I have an under-counter heater, I haven't installed it because there is a simpler source of water at the correct temperature. I try to keep the darkroom at a temperature practical for film development. A supply of water stored in the darkroom is the same temperature as the chemicals and film tank. Washing the prints in trays requires only a modest amount of water.
     
  8. Matt5791

    Matt5791 Subscriber

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    Thanks for the replies! very helpful.

    Bob - I was thinging about the type of heater you use.

    Thanks,

    Matt
     
  9. Pragmatist

    Pragmatist Member

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    Jim, this is the beauty of basement darkrooms. It is so much easier and cost efficient to keep the temperature "photo" ready. In the winter, spring, and fall, it is simply to run everything at 68F. Late last summer (when I completed building it), with the exception of the hottest week of the year it stayed at 68F with the assist of a small window AC that would kick on for a few hours about mid-day. The "hot week" everything ran at 72F.

    I have used the in-line units in materials analysis labs, and they are pretty good for what they are intended for: the provision of small quantites of warm/hot water. Most often they are sufficient for a tempering bath or a small quantity of water for preparing solutions. And as noted, depending on the incoming water temperature, balancing of wash water. Continuous flow of "hot" water? Usually not. Here is a selection of conventional tank solutions:

    http://www.americanwaterheater.com/WHBrowser/res_elec.cfm

    There are small under sink hot water heaters of 2 to 20 gallons so. Intended for "immediate" hot supply in bathroom and wet bar sinks, they can do the same; provide a small quantity of hot water for a tempering bath or mix-up. When the tank runs out, it takes quite a while for the temperature to recover. They can be cost ineffective as well, but the larger ones can supply quite a darkroom operation quite well.

    The next jump up is the compact, or "mobile home" size heater. These are generally 30-40 gallon, and are squat for undercounter, or tall and slim for corner mount. Usually more hot water than you will ever need, but the space and need must be there.

    Tying into the existing residential HW system is always the better and most cost effective solution. IF possible.

    Regardless of the solution chosen, THIS IS THE MOST IMPORTANT PART!!! The plumbing from the HW heater must be of an approved type. White PVC is just fine for cold water supply in a home. But, never directly connect a PVC pipe or fitting to the cold water inlet of a water heater, or use any kind of white schedule 40 anywhere in the hot water circuit. This stuff behaves funny above 100F, and will start to leak around any screw type fitting in no time at all. ALWAYS use CPVC (the creme colored stuff), copper line, or galvanized pipe for hot water connections. Also, NEVER USE SCHEDULE 20 PVC pipe for pressurized lines!!! This stuff is for waste connections and venting only.