Support our Sponsors, they keep FADU free:   AG Photographic   The Imaging Warehouse   Process Supplies   RH Designs   Second-hand Darkroom Supplies  

Notices

Go Back   Film and Darkroom User > Equipment > Darkroom

  ***   Click here for the FADU 2015/2014 Yearbooks   ***

Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 24th February 2014, 06:44 PM
Tony Marlow Tony Marlow is offline
Friend
 
Join Date: Sep 2008
Posts: 1,282
Default

I have a copper cylinder and a Pro-Co thermostatic mixer cost me £7 at a camera sale. The immersion heater keeps the tank hot (set at min. 55degC) easily as it does not take much hot water to maintain a temperature of 20 to 25C. It does need a small header tank which all fits into my garden shed. I would say you could get reasonable control with a shower mixer or even two gate valves in the cold and hot water supply before joining them to a tap. The gate valves would give pretty fine flow adjustment.

Tony
Reply With Quote
  #12  
Old 24th February 2014, 07:00 PM
JOReynolds JOReynolds is offline
Friend
 
Join Date: Nov 2012
Location: St Albans UK/Agde France
Posts: 1,074
Default

The widest range of continuous-flow electric heaters is from the German company Stiebel-Eltron. They are intended for use with mains water pressure and won't work at all with typical loft-mounted storage tanks because the safety device will actuate at low pressure. The output is suitable for use with a thermostatic water mixing valve.
Storage hot tanks intended for domestic use are bulky and expensive and also require a thermostatic mixing valve because the heated water forms layers, hot at the top, cold at the bottom.
The alternative is to install an inexpensive 3kW continuous-flow water heater intended for hand washing, which can be plugged into a UK standard 13A socket. It is also intended for mains pressure. This type has the flow control on the inlet - the vessel enclosing the heating element cannot withstand the pressure of a closed-off outlet. The temperature depends on the incoming temperature and is adjusted by limiting the flow. The performance is given by the equation (watts x seconds) / 4.2 = calories = temperature rise (in deg C) x volume (in ml). So if the incoming water temperature is 8 deg C and the desired temperature is 30 deg C, a rise of 22 deg C, the system will yield 1938ml, around 2 litres, per minute. If you set a temperature of 20 deg C (12 deg C rise) you will get 4.3 litres per minute. You will of course need a thermometer.

Last edited by JOReynolds; 24th February 2014 at 07:03 PM.
Reply With Quote
  #13  
Old 24th February 2014, 10:35 PM
Xpres's Avatar
Xpres Xpres is offline
Friend
 
Join Date: Nov 2009
Location: Stansted
Posts: 975
Default

I pondered a lot in this question when I built my darkroom. The cheapest way is to do as Tony has done with a thermostatic mixer and a hot and cold supply. In the end though I went for accuracy and a wide temperature range from a pro co instant heater unit I picked up off ebay. It soon died. So I coughed up for an American eemax heater and doubled the cost of my darkroom .... but I have water at 20 deg or 40 deg whenever I want.
Reply With Quote
  #14  
Old 24th February 2014, 11:42 PM
Argentum's Avatar
Argentum Argentum is offline
Friend
 
Join Date: Sep 2008
Location: Sceptred Isle
Posts: 3,066
Default

Quote:
Originally Posted by Xpres View Post
I pondered a lot in this question when I built my darkroom. The cheapest way is to do as Tony has done with a thermostatic mixer and a hot and cold supply. In the end though I went for accuracy and a wide temperature range from a pro co instant heater unit I picked up off ebay. It soon died. So I coughed up for an American eemax heater and doubled the cost of my darkroom .... but I have water at 20 deg or 40 deg whenever I want.
which eemax unit did you get and will it work with slow enough flow rate for print washing at 20deg C
Reply With Quote
  #15  
Old 25th February 2014, 08:15 AM
Jeff Sheff Jeff Sheff is offline
Friend
 
Join Date: Aug 2013
Location: Rotherham
Posts: 63
Default

Thanks for all your replies. It is obviously a lot more complicated than I first thought. What does everyone else do when washing FB paper? Do you run it straight from the cold tap or use water a little warmer? Do the Heatrae type heaters plug into the normal ring main?
Reply With Quote
  #16  
Old 25th February 2014, 08:55 AM
JOReynolds JOReynolds is offline
Friend
 
Join Date: Nov 2012
Location: St Albans UK/Agde France
Posts: 1,074
Default

Jeff - Heatrae manufactures a range of heaters, some of which can be plugged into a 13A ring main. PM a description of what you need and I will do the calculation.
Reply With Quote
  #17  
Old 25th February 2014, 09:22 AM
Xpres's Avatar
Xpres Xpres is offline
Friend
 
Join Date: Nov 2009
Location: Stansted
Posts: 975
Default

Quote:
Originally Posted by Argentum View Post
which eemax unit did you get and will it work with slow enough flow rate for print washing at 20deg C
It's an EX75T which works fine with print washing. I connect to a nova wash when printing and to my deep tank when processing. At the moment, though it's hooked up to a kodak tray syphon on a Tupperware box for the washes in my C41 'line'. You have to get the flow right though or it will keep cutting out, but that's really at a dribble.
Water coming in is at 2bar... not sure what the minimum is for the unit.
I also run it through a filter after the water is heated rather than before.
Reply With Quote
  #18  
Old 25th February 2014, 10:01 AM
Tony Marlow Tony Marlow is offline
Friend
 
Join Date: Sep 2008
Posts: 1,282
Default

Just wonder how importent water temperature is for washing prints. Ilford times for washing are for temperatures above 5degC with no reduced times for warmer water. I doubt if mains water temperature falls below 5degC except on very rare occasions.

Tony
Reply With Quote
  #19  
Old 25th February 2014, 10:59 AM
Jeff Sheff Jeff Sheff is offline
Friend
 
Join Date: Aug 2013
Location: Rotherham
Posts: 63
Default

Having read through all the replies I'm certainly a lot wiser than before. I did nearly buy one off ebay but after reading forum replies I decided to pause. The one off ebay sounded just right, about £50 fitted under the sink and temperature depended on flow so my thoughts were to fine tune the flow to get the right temp. In the end they said I needed a separate 16A supply so abandoned that. As Tony says if print washing above 5 is fine then perhaps just having one of the wall mounted storage ones for washing and chemical mixing use you would suffice. This has all been triggered because I picked up a 4' x 2' Pro Co sink off ebay in wonderful condition for a song. I have been using a corroded domestic sink but when you are washing trays the stuff gets everywhere so now I will be able wash the trays with plenty of room to spare.
Reply With Quote
Reply
Support our Sponsors, they keep FADU free:   AG Photographic   The Imaging Warehouse   Process Supplies   RH Designs   Second-hand Darkroom Supplies  

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Darkroom water, waste and climate mickthurman Photography in general 0 30th January 2014 10:58 AM
Nova slot processor heater failed Stan160 Darkroom 22 27th November 2012 08:33 AM
RO water instead de-ionised water Andrew F Darkroom 5 11th July 2012 06:35 PM
Darkroom Water Heaters RoyFleming Darkroom 10 9th July 2011 08:38 AM
Street (Water, Water Everywhere but Not a Drop to Drink) Mark-NY Art and aesthetics 12 22nd May 2011 09:51 AM


All times are GMT. The time now is 11:56 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.