Darkroom Water Heater

msage · Sep 12, 2005

I am building a BXW darkroom (stand alone) and wonder how big of a water heater I need? I will being processing roll and sheet film (semi-stand and Jobo) and printing (mainly fiber). Any ideas?
Thanks
Michael

dancqu · Sep 12, 2005

msage said:
... a water heater I need?

If you've the electricity consider a tankless with
photo-lab temperature control. Dan

raucousimages · Sep 12, 2005

I have just installed a bosch tankless natural gas heater in a small house, It works great. They are available in LPG, NG and electric.

John Koehrer · Sep 12, 2005

Yep, a tankless is probably the way to go. It only heats when the water flows, so tend to be inexpensive to run. Is very compact since it has no storage tank & gives you more room for other storage. etc. etc.

Loose Gravel · Sep 12, 2005

I have two tankless water heaters in my place. I love them and they work well, but I don't know that they are perfect for a darkroom. Maybe the electric ones would be okay, but mine are gas and won't turn on until there is a minimum flow of 1/2 gallon per minute. Below this, it's cold. If you need just hot, this works, but if you need warm water (cold and a little hot) for washing prints and such, you're had.

A small electric under the counter might work better and is certainly cheaper. You can buy a 6 gallon and this might be fine. Just turn it on only when in the dark. Maybe someone here has tried this.

David Brown · Sep 12, 2005

Loose Gravel said:
A small electric under the counter might work better and is certainly cheaper. You can buy a 6 gallon and this might be fine. Just turn it on only when in the dark. Maybe someone here has tried this.

I put a 2 gallon in mine. I don't need it for washing (Texas) and I figured I'd only need hot water for mixing powdered chems. Well, a 2 gallon heater is not enough for anything! Takes a long time to heat up, then is gone in seconds. Yes, I can get enough to mix a gallon of Dektol, but it's less trouble just to heat the water in the microwave. YMMV

A larger one would have to be better if you have the space!!!

David

Paul Howell · Sep 12, 2005

What do you want the hot water for? If its for a water bath for printing or C41/E 6 processing either a tank or a tankless unit will work depending on the temp of your darkroom, if is just for mixing consider liquid concentrates or a hot plate. When I lived in Northern California I had a small sink and I used 2 fish tank heater to keep the trays to 68.

kwmullet · Sep 12, 2005

I've got to second the idea of a tankless heater. I did a quick google search and this is the first page I came up with:
http://www.plumbingstore.com/index-tanklesswaterheaters.html

When I build my next darkroom, I plan on either a point-of-use or the next size up water heater. For B&W, though, depending on where you live, expect the water heater to mostly be useful only for chemical mixing and for bringing winter water up to 68f or so.

I anticipate a water chiller to be a greater value in the darkroom, and I'll probably end up doing a variation on this:
http://www.yoshi.us/forums/showthread.php?t=8577&page=7&pp=10

basically just find a cheap cruddy dorm or under-the-desk fridge from a resale shop, drill and place input and output lines in the top and run the water through as many feet of coiled copper tubing as I can fit in the fridge and set the temp to about 40.

-KwM-

msage · Sep 12, 2005

Thanks for the feedback. My experience with "on demand" has not been good. You have to have a flow rate too high to maintain a stable 68 degrees. We have one at work and I hate it!!! The plumber thinks a 19 Gal. water heater will be fine. As in my first post, I will being processing roll and sheet film (semi-stand and Jobo) and printing (mainly fiber). I usually don't use a running water bath to maintain temp. I add hot or cold as needed. The most use of the water heater would be maintaining the wash water temp. I use liquid concentrates and very little powered chemicals that need to be mixed at higher temps.

More on tankless heaters, they work well on higher temps (great on the E-6 line at work), not so good on lower temps (BXW at 68 degrees). IMHO

Michael

kwmullet · Sep 12, 2005

msage said:
[...]
More on tankless heaters, they work well on higher temps (great on the E-6 line at work), not so good on lower temps (BXW at 68 degrees). IMHO

Michael

Interesting. After looking more closely, I see they've got a little editorial blurb on that site I mentioned that 110v/15amp tankless heaters just plain don't work well. I notice that they all require pretty hefty power (the electric ones).

Do you have any experience with the larger (whole house) tankless heaters? Gas or electric?

-KwM-

lee · Sep 12, 2005

I have a 30 gal tank I plumbed into the hot water side of my darkroom. Dont use is much this time of year but several months a year I do need to warm up the water. Mine is 220vac.

lee\c

dancqu · Sep 14, 2005

Loose Gravel said:
...won't turn on until there is a minimum flow
of 1/2 gallon per minute.

At what flow per minute does it turn off?
I've shopped the electrics and find 1/2
gallon turn on typical even of the
small units.

BTW do you know of the units with thermostat?
Dial the temperature. Skip the cold water plumbing!
The darkroom thermostat model will deliver +/- .5F
at any temperature of usual interest. Dan

Bob F. · Sep 14, 2005

I don't think wash water temp is terribly critical. Anything from around 20 to 25C will do fine. I use a 3kW instant heater which works well in London's climate (i.e. air temperature rarely outside the 5C to 25C range). A 6kW shower unit will work too as long as it has a reasonable thermostat and you can control the flow rate independently to the temperature, although that will need its own power line from the main fuse-box.

Good luck with the build! Bob.

msage · Sep 18, 2005

I think I will try a 19 gallon HWH. Keep you posted.
Michael

Loose Gravel · Sep 19, 2005

dancqu said:
At what flow per minute does it turn off?
I've shopped the electrics and find 1/2
gallon turn on typical even of the
small units.

BTW do you know of the units with thermostat?
Dial the temperature. Skip the cold water plumbing!
The darkroom thermostat model will deliver +/- .5F
at any temperature of usual interest. Dan

Dan, the one for my darkroom, guest room, laudry room is an Aquastar 38B. It turns ON at 1/2 gal/min and turns off below this amount. I have a thermostat model, a Takagi TK-1, for my house showers. It puts out 120F water from 1/2 gal/min to about 4 gal/min depending on the inlet temperature. It has some hysteresis between turn on/off, but I don't remember how much. Might have been 3/4 gal/min ON and 1/2 OFF.

MurrayMinchin · Nov 13, 2006

Bump!

There's been whisperings that our 12' x 25' garage may be re-born as a darkroom and a mat cutting/framing/print storage room this spring.

I contacted this company (Stiebel Eltron) and they recommended this electric heater which turns on with just .29 gallons of water per minute;

Dead Link Removed

Anybody else have experience with these types of water heaters?

Jim Jones · Nov 14, 2006

First, determine just how much hot water you need. A print washer might require much; tray washing very little. If I ever get around to remodelling my darkroom, I have an under-counter heater for it. Input will be through a two stage water filter; nice for the darkroom but overkill for the rest of the house. A high volume print washer would require something else.

Darkroom Water Heater

Membership Council

Privacy & Transparency

Privacy & Transparency