Maintaining 68° with tankless water heater

[Mark_Turner]

I have two tankless, propane fired water heaters. Impossible for darkroom. A 5 gal electric water heater in my darkroom I turn-on as needed.

That's the option I'm considering, with the on-demand water heater feeding into the electric as a pre-heater when there's sufficient flow.

[Jim Noel]

Careful processing does not require a 5 gallon tank.
I fill a 2 liter container with water at correct temp. I mix chemistry for processing and collect 2 more liters for use in washing. To wash I use 5 changes of water. On occasion I need to draw some more water at correct temp, but certainly not 5 gallons. I use a fill and dump process to wash.

[Leszek Vogt]

Mark, this may be a home made remedy, but it may help. Essentially you keep everything in trays the same temp.

https://www.amazon.com/s?k=seedlings...ref=nb_sb_noss

[mpirie]

I use a tankless water heater which is fine for running water at 20 ˚C in summer, but because the incoming water is around 5 ˚C in winter, the heater struggles to heat the water enough when it comes to washing film.

The heated water passes through a ProCo thermostatic mixer, but as the temp drops, the flow is restricted (unlike the Hass).

Chemicals are heated up in the recycling of water in a Jobo, so water for the dev, stop and fixer are all on temp.

Mike

[Tin Can]

Many ways to control fluid temp

For decades I designed, installed and operated rapid high volume valved systems that moved fluid from -35 F to 260 F in 30 seconds

Thermo shock IC engines, cost $1MM

Less is easy

Hass

[Luis-F-S]

That's the option I'm considering, with the on-demand water heater feeding into the electric as a pre-heater when there's sufficient flow.

That would be your best option, not the cheapest though. If your inlet cold is always under 68 Deg F, I'd invest in an Intellifaucet. I've bought the two I have used from less than 1/2 to 1/3 of the new cost.

[Mark_Turner]

That would be your best option, not the cheapest though. If your inlet cold is always under 68 Deg F, I'd invest in an Intellifaucet. I've bought the two I have used from less than 1/2 to 1/3 of the new cost.

Our cold water is always below 68°F as it comes from our well and we don't have all that many days each year when the air temperature is much above that. The issue is that the on-demand water heater shuts off when the flow is below a certain point (that I haven't determined). How does an Intellifaucet deal with that?

[Luis-F-S]

A Hass intellifaucet is a very accurate electronic mixing valve that maintains whatever temperature you set as long as it's between the incoming cold and hot tap temperature. It does nothing to make your tankless water heater work which is why you will probably need to add a small tank water heater. You can have the tankless WH in line with the tank WH, so you will have a supply of hot water once the Tankless WH shuts down. You should be able to add the small tank WH to your hot supply line. The intellifaucet will work at very low flows down to a trickle. You only need the smallest one for darkroom work, either the electronic K250 or the manual (budget) D-250. If your cold tap is always below 68 deg F, then you can maintain 68 deg by mixing the cold and hot tap from your tank water heater. Have you checked with the tankless WH manufacturer to see if they have any suggestions? The photo below shows a 10 gal water heater(the white tank) which feeds the hot tap for the darkroom. The blue tank is a pressure tank for the well pump. There is a single filter ahead of where the cold line splits to go to the water heater. I've since run a potable water line to this setup making the water filter redundant. Good luck.



My darkroom design is in this thread:

https://www.largeformatphotography.i...highlight=K250

[Jim Andrada]

Opposite problem here - the "cold" water can get up to almost 90 in the Summer. One "solution" has to been to use Ilford XP-2 in the summer since it's a c41 process. But that only works for MF

I've been thinking about installing a chiller. But for now I just run a couple of bottles of hot water and cool them down with ice cubes. It doesn't take long at all.

[Tin Can]

I am sure Jim, you have AC. I lived in Valley of the Sun when Swamp Coolers almost still worked

Storing water inside any HVAC environment will act as stabilizing thermal mass and be useable for B&W film and paper directly

Emulsions and processing are adaptable to any environment humans can survive naked