Goin' green in the darkroom!

Rich Ullsmith · Jul 17, 2010

Cautionary tale. After ten years of the wife turning the gas-powered hot water heater up to that notch just past VERY HOT (yep, ours goes to 11!)
it finally crapped the bed in grand fashion. Much to my delight, because now we can get one of those tankless heaters. No more watching my wash temperatures bounce between 59f and 95f in a matter of seconds when someone wants to take a bath!

Developed my first films today. Turned the hot and cold knobs, figuring it would warm up pretty quick, then adjust from there.

Five minutes later, no warm water. Shut the cold off. Five more minutes, no warm water. Me very confused. I just used hot water half an hour ago in the kitchen. Go to the kitchen, and immediately there is hot water.

Turns out that my darkroom tap doesn't draw water fast enough to activate the heater. So, here in the land of unintended consequences, in order to develop and wash films using my government subsidized green tankless water heater, I need a hot water tap turned on somewhere else in the house. Who'da thunk it?

Anybody with an idea or resource for solving this problem that doesn't involve plumbers, I'd love to hear about it.

Jan Pietrzak · Jul 17, 2010

Rich,

Most all of the tankless heaters work on a flow rate, and some times it is just to low to work. I looked at this for my new darkroom/studio. What did we do a small electric unit (we have an all electric house). It work just fine. In the winter the ground is at 20 to 30 degrees and the cold water is just that cold!

Ok fixing the problem you may need to have a hot water holding tank so you can control temps.

Jan Pietrzak

Tom Kershaw · Jul 17, 2010

Rich,

I had this problem when I tried to use a tankless heater in the darkroom; you also have the issue of the high electrical load, my unit was 9.5 kW.

Tom

Steve Smith · Jul 17, 2010

Rich Ullsmith said:
Anybody with an idea or resource for solving this problem that doesn't involve plumbers, I'd love to hear about it.

Yes..... Do your own plumbing!

Perhaps one of the pumps which is used to increase the flow rate for showers. Do you have those in the US? (the pumps, not showers!).

Steve.

L Gebhardt · Jul 17, 2010

For films use the Ilford method of soak and dump. I use this for both film and paper. I use more water changes than they recommend. The results are great.

Your experience is precisely why I won't get one of these heaters. I experienced one at my parents' house. I usually take a long low flow shower, turning up the flow just for the final rinse. Their water heater would cycle between hot and cold at anything other than full water flow.

My next heater will be one of the heat pump units. I'll get free dehumidification in the summer which should cut the electric bill greatly. My gas heater costs almost as much to run as the prior electric one, so the heat pump should save at bit.

bdial · Jul 17, 2010

I have a tankless water heater, and hot water for the darkroom is a PITA, for the reasons mentioned. I worked around it to a degree by running the hot water full blast until it got the pipes between me and the water heater full of warmed water, then switched to the tempered water for the film or print washer, or whatever. Another possibility is to do laundry or run the dishwasher or something while you're doing your darkroom thing.

The real answer which is what I did a few months ago is to install a small point of use water heater under the sink, plumbed into the hot water. Not quite as green, but functional, they heat quickly, so you could turn it off when you won't be doing DR stuff for a while.

I've also seen recommendations to expand from that and install something like a 10 gallon tank water heater on the hot water line following the tankless. You don't spend the money to keep 30+ gallons hot, but it bridges the gaps and provides hot water in the low flow situations.

There are many things I really like about our tankless heater, but this is one of the weak areas.

Rick A · Jul 17, 2010

Go ahead and replace the house tank with whatever you want, and put a 4 or 5 gallon point of use electric tank in the darkroom for your own use. They are small enough to fit under the counter and for what little bit you use, will work out perfectly.

jmcd · Jul 17, 2010

I had this problem in my darkroom, after I installed a tankless water heater. I solved it by replacing it with a regular tank water heater.

Some tankless water heaters allow you to dial down the hot water temp, such that you could use more volume running through the heater to get the temperature you need without the heater shutting off.

RalphLambrecht · Jul 17, 2010

I've never been able to make a tankless heater work in the darkroom. Modern archival washers work with flow rates far below the tankless heater initiation point. Nothing beats a nice hot water reservoir.

donbga · Jul 17, 2010

Rich Ullsmith said:
Cautionary tale. After ten years of the wife turning the gas-powered hot water heater up to that notch just past VERY HOT (yep, ours goes to 11!)
it finally crapped the bed in grand fashion. Much to my delight, because now we can get one of those tankless heaters. No more watching my wash temperatures bounce between 59f and 95f in a matter of seconds when someone wants to take a bath!

Developed my first films today. Turned the hot and cold knobs, figuring it would warm up pretty quick, then adjust from there.

Five minutes later, no warm water. Shut the cold off. Five more minutes, no warm water. Me very confused. I just used hot water half an hour ago in the kitchen. Go to the kitchen, and immediately there is hot water.

Turns out that my darkroom tap doesn't draw water fast enough to activate the heater. So, here in the land of unintended consequences, in order to develop and wash films using my government subsidized green tankless water heater, I need a hot water tap turned on somewhere else in the house. Who'da thunk it?

Anybody with an idea or resource for solving this problem that doesn't involve plumbers, I'd love to hear about it.

Install an 80 gal. GE Smart electric water heater. If possible partition the hot water lines in your home so the tankless supplies the baths and other high demand areas like dishwasher and laundry.

The electric smart water heaters don't heat the water all the time but have 2 5000W elements (only one turns on at a time) to produce a constant source of hot water when demanded by the flow rate of cold water entering the heater. We don't miss our gas heater at all. It does require a dedicated 30AMP circuit.

I was never sold on the tankless systems for a number of reasons. I also recommend a whole house filter and an incoming filter for the hot water heater. It's amazing to see how dirty tap water is. I live in a fairly young home about 2 miles away from a new 4 billion (yes that's billion with a B) dollar county water processing plant. In my darkroom I have additional filtration on the hot and cold incoming and a chlorine filter on the outgoing water. This really helps reduce crude on film after washing.

Good luck!

RalphLambrecht · Jul 18, 2010

Don

That's excellent advise. Thanks for sharing.

Tom Kershaw · Jul 18, 2010

RalphLambrecht said:
Don

That's excellent advise. Thanks for sharing.

Ralph,

Does your darkroom hot water supply run off large tank (say 250L) or a smaller in-situ model, e.g. 50L or 15L?

Tom

RalphLambrecht · Jul 18, 2010

Tom

I'm using the one that supplies the entire house. It has a capacity of 120 Liters. My only problem was people using cold water somewhere else in the house (flushing the toilet), which made the water temperature in the darkroom move up rapidly. This is now fixed by controlling the water temperature in the darkroom via an Intellifaucet. This water controller is the best thing I've ever bought for the darkroom. Set the temperature and forget about it!

Tom Kershaw · Jul 18, 2010

RalphLambrecht said:
Tom

I'm using the one that supplies the entire house. It has a capacity of 120 Liters. My only problem was people using cold water somewhere else in the house (flushing the toilet), which made the water temperature in the darkroom move up rapidly. This is now fixed by controlling the water temperature in the darkroom via an Intellifaucet. This water controller is the best thing I've ever bought for the darkroom. Set the temperature and forget about it!

I have the basic Intellifaucet model which indeed is a huge convenience; however, no hot water as the tank isn't supported anymore by the manufacturer and the element has gone so will need to investigate other options. One of the 15L 3kW units is attractive as the installation can be rather less involved, although in "winter" (October to May) I'm not sure whether the 15L capacity and reheat time will be sufficient for washing fibre base papers @ 20ºC. I'll have to try and find my calculations.

Tom

Curt · Jul 18, 2010

I once hear of a couple who bought a new house and when they flushed the toilet it was steaming, someone hooked it up to the hot water line. Good thing they didn't have a bidet.

donbga · Jul 18, 2010

RalphLambrecht said:
Don

That's excellent advise. Thanks for sharing.

It was a bit long winded but thanks!

sepiareverb · Jul 18, 2010

There are (or were) low flow tankless heaters back in the early 90s, I had one. No memory of what brand. We had a low flow shower head that wouldn't have worked with the standard flow tankless heaters- I suppose unpleasant equals short showers, and thus a lot of savings.

I'm currently getting hot water from an old propane hot water heater that serves the whole house. Water is pre-heated in winter by our geo-thermal forced hot air system. Mixing valve keeps temps consistent.

Rich Ullsmith · Jul 18, 2010

So what I'm hearing is, a separate electric tank for the darkroom. I had no clue that there could be a worse system for obtaining consistent 70f than the old tank, until this.

RalphLambrecht · Jul 19, 2010

Rich Ullsmith said:
So what I'm hearing is, a separate electric tank for the darkroom. I had no clue that there could be a worse system for obtaining consistent 70f than the old tank, until this.

It doesn't have to be electric, but having a tank definitely helps.

Rick A · Jul 19, 2010

The reason I recommend electric tanks is the relative ease of installation. Its easier to run wire than gas lines to existing structures, not to mention much cheaper.

Rich Ullsmith · Jul 19, 2010

Are there any sort of plug-in models out there? Sans new plumbing, I can only draw about a gallon per minute total, so to operate in winter I would probably need a constant 90-95f at about half gallon per minute. Seems like there should be something out there for livestock, to keep water from freezing.

mgb74 · Jul 19, 2010

There are very small electric units that plug into 120v outlet. I don't know where you are located but Home Depot (for example) has a couple of different 2.5gal. But you have to look at the amp draw and the wiring you have available. For example, the 2.5gal model draws 12.5 amps - which might be OK depending on the circuit. A 6 gal, 120v model draws 16.7 amps - too much for most existing home 120v wiring.

Without going into too much detail, you probably have a 15amp circuit on 14 ga wiring (if in US). So the 6 gal will draw too much current. The 2.5gal would be ok IF there is not too much else drawing on that circuit when the water heater turns on. If your wiring is 12ga, you might have a 20amp breaker so you'll be OK with the 2.5gal and marginal with the 6 gal. Look at the circuit breaker in the box for that circuit and see if it's marked 15amp or 20amp.

Another possibility might be one of the very small tankless heaters designed for under the sink cabinet. They might have much less flow requirement to initiate heating.

RalphLambrecht · Jul 19, 2010

ralnphot said:
The reason I recommend electric tanks is the relative ease of installation. Its easier to run wire than gas lines to existing structures, not to mention much cheaper.

'We choose to go to the moon, and do the other things, not because they are easy, but because they are hard.'

John F. Kennedy

RalphLambrecht · Jul 19, 2010

mgb74 said:
There are very small electric units that plug into 120v outlet. I don't know where you are located but Home Depot (for example) has a couple of different 2.5gal. But you have to look at the amp draw and the wiring you have available. For example, the 2.5gal model draws 12.5 amps - which might be OK depending on the circuit. A 6 gal, 120v model draws 16.7 amps - too much for most existing home 120v wiring.

Without going into too much detail, you probably have a 15amp circuit on 14 ga wiring (if in US). So the 6 gal will draw too much current. The 2.5gal would be ok IF there is not too much else drawing on that circuit when the water heater turns on. If your wiring is 12ga, you might have a 20amp breaker so you'll be OK with the 2.5gal and marginal with the 6 gal. Look at the circuit breaker in the box for that circuit and see if it's marked 15amp or 20amp.

Another possibility might be one of the very small tankless heaters designed for under the sink cabinet. They might have much less flow requirement to initiate heating.

I think with this you're back to the flow-rate problem, and don't even think about making consistent exposures when this thing kicks in.

Tom Kershaw · Jul 19, 2010

Ralph,

Imagine the power drop when a 9.5kW instant unit kicks in, even on 240V. There is three phase here but wiring sensitive items onto the spare phase would be complicated.

Tom

Goin' green in the darkroom!

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