New darkroom.... water supply questions

[Jehu]

I'm setting up my new darkroom in a small room in my studio. I need to look at the water supply. My office has one of those little 7 gallon water heaters. It's in the space over the restroom so there's no room for a taller one. Perhaps either a larger, short model or a second one next to it would work. My last office had the same size. It was barely sufficient for E-6 in my Jobo.

I was looking at this:
http://www.amazon.com/gp/product/B001LZRF9M?keywords=tankless%20water%20heater&qid=1447701350&ref_=sr_1_3&s=kitchen-bath&sr=1-3

It seems like quite a good deal for the price. Has anyone else tried tankless supply? I've heard bad things about their consistency.

[Luis-F-S]

Not sure of the water requirements for a Jobo for E-6, I have a 7 gal WH outside my darkroom which is more than adequate. Had a 5 gal at my last darkroom without any issues. The tankless WH have pretty high energy demands. Make sure you have a dedicated 240 v circuit for it. Also check into whether you can pipe the electric WH into the tankless feed line. If you use an Intellifaucet, it will take care of any temp fluctuations. With an automatic control valve, good luck! L

[Tin Can]

I have rejected tank-less WH for darkroom supply as often we want a trickle for washing and a big tank does that better for less as Luis points out.

I may go to big holding tanks anywhere I can put them as room ambient temp stored water is fine for wash and buffers the heating and cooling requirements in a varying climate.

Of course those tanks need flow to keep them clean, but that's easily incorporated.

[Renato Tonelli]

Tankless water heaters are very common in Europe. My experience with the one I have is that it is difficult to control temperature especially at low flow rates.

[Old-N-Feeble]

Tankless water heaters are very common in Europe. My experience with the one I have is that it is difficult to control temperature especially at low flow rates.

I like tankless water heaters but... one must assure the electrical supply can handle the immense current draw from one. Regarding rapid temperature changes... the way to deal with that is to have a small tank heater and supplement it with a tankless heater... the tankless heater feeds into the tank heater which acts as a mixer/moderator for rapid temperature changes. Of course, the temp may slowly decrease over time but the rapid changes are gone.

[Nigel Smith]

no experience with electric instant HWS but we have a gas one. It's no good for a low flow of hot water, just doesn't fire up without a certain flow which is more than I ever want to wash anything (film, paper). It's a combination of the minimum flow and the minimum temp possible which is 38C (I think), so to get down to 20C you need to add so much cold that the flow is too great. It is very consistent once running, just not usable! None of this really relates to the OP's question, however it may be of use to someone someday :-) On a positive note, I wouldn't have a stored HWS if I had the choice, the gas is terrific for every normal household purpose. Never run out of hot water... except if the power fails, then it won't start up at all!

[jp]

This little electric heater uses more power than a big electric hot water heater (60 amp breaker compared to a typical water heater's 30a breaker) because it's meant to work quick. Unless your electrical panel is in the darkroom, you'll probably exceed the cost of the heater in wiring and electrician costs. You could probably spend >$100 just for a double breaker and enough 6/2 wire for a short run if you're qualified to wire it yourself.

There's a place I go where the kitchen is served with a tankless propane heater and it comes on when the water flows and takes a minute or so to get up to temperature. It's fine for washing dishes and such, I haven't tried it for low-flow use.

At my house for hot water I have a 130 gallon tank heated by solar panels (glycol pumped through the panels). Boiler comes on as backup. We go for months at a time without boiler use in the summer as that's enough water for MANY hot showers for the whole family, dish/clothes washing, and darkroom use.

[Duolab123]

I like tankless water heaters but... one must assure the electrical supply can handle the immense current draw from one. Regarding rapid temperature changes... the way to deal with that is to have a small tank heater and supplement it with a tankless heater... the tankless heater feeds into the tank heater which acts as a mixer/moderator for rapid temperature changes. Of course, the temp may slowly decrease over time but the rapid changes are gone.

I'm fortunate that I was able to get my hands on a nice thermostatic mixing valve cheap. These things are great as long as you have COLD and hot water. E-6 @ 100 F your 7 gal. Should be adequate, I do agree that I would put the tankless inline before the tank, just set the tankless so it feeds your 7 gallon unit with 85-95 F water, you should have all you need for processing.

I think most places in Europe especially Germany use tankless, I saw one hotel that had insulated plumbing pipes and the water circulated constantly so when you jumped in the shower it was ready to go,no wasting water. I think this was common in the good old days in commercial labs. Big buildings for b&w its often hard to keep things cool.

[HMG]

First, check the thermostat on your little heater. Most are preset at 125 dF to avoid scald injury but can be set higher. If still worried about safety (if the heater feeds a bathroom sink), you can install a mixing valve (http://www.amazon.com/Honeywell-AM101C-Thermostatic-Mixing-Valve/dp/B0098TG3CI/ref=sr_1_1?s=hi&ie=UTF8&qid=1451247789&sr=1-1&keywords=water+heater+mixing+valve). Without doing the math, it might turn your 7 gal 125 deg water heater into an effective 9 gal one.

Alternatively, a 2nd small water heater could be used, but you're doubling you power requirements.

[Graham Patterson]

We just had a gas tank-less unit installed in the house. It was that or have the old tank closet significantly expanded so we could get a newer extra insulated and physically larger unit installed. We do not use a great deal of hot water (there are only two of us), so it made sense.

But it is next to useless for low-flow, constant temperature supply. Fortunately I don't do anything that requires more hot water than an electric kettle and some insulated jugs can provide.

[StoneNYC]

We just had a gas tank-less unit installed in the house. It was that or have the old tank closet significantly expanded so we could get a newer extra insulated and physically larger unit installed. We do not use a great deal of hot water (there are only two of us), so it made sense.

But it is next to useless for low-flow, constant temperature supply. Fortunately I don't do anything that requires more hot water than an electric kettle and some insulated jugs can provide.

They are great if tuned properly, if not they make a lot of whiny noise. Glad it's solved.

[Drew Wiley]

Good tankless on-demand heaters are expensive. But in the long haul it depends where you live. Here natural gas is far more economical to heat water with than excess wattage, which you have to be wired for.

[StoneNYC]

Good tankless on-demand heaters are expensive. But in the long haul it depends where you live. Here natural gas is far more economical to heat water with than excess wattage, which you have to be wired for.

I'm not sure if the government is still running this program, but a few years ago when I got mine, they were compensating with either some kind of refund or text reduction, so it ended up being the same price as a normal water heater for me. Part of the whole green low energy usage initiative.