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ECO27 Details and Conversion to Boiler Mode - In Depth
on November 12, 2013
Some information about this unit (and the entire product line) is sparse, and numerous people have posted inaccurate information as well. First, RTFM. EcoSmart provides a wealth of information online, and all of us would do well to check their site before posting bad information.
I have two of these units, one for DHW (Domestic Hot Water) and the other to operate our whole house hot water baseboard system. Some information is hard to find, and other information is a closely guarded secret and cannot be obtained anywhere online. I'll focus on these areas.
The unit is rated at 27KW at 240 volts. Internally, it is three separate 9KW heaters, operating in series and in sequence based on demand. The unit is truly self-modulating and will not provide more heat than the load requires.
Each individual heater requires a dedicated 240 circuit, rated at 40 amps, and provided via #8 wire. For the Ohm's law fanatics, each unit draws 37.5 amps under full load, for a total system load of 112.5 amps. Anybody that tries to operate this unit off of a 100 amp main breaker deserves what he gets. We have ours connected to our main 150 service, and can get away with it because everything else in the house is "green" and we can operate everything else with the 37.5 amps available if the heater is running under full load.
I'll say this again: Each internal unit requires a separate, dedicated 240 volt 40 amp circuit, equalling a total of three separate #8 wire 240 volt circuits. I hope I made that plain enough.
The heat exchangers inside the heater are 3 copper pipes, cross connected in series with about 1/2" dia. copper sections. So there is a flow restriction, but nothing as radical as some of the reviews would have us believe. Some reviewers have posted that their hot water is down to a trickle. I've been inside this unit from top to bottom. If your hot water only dribbles, it is time to clean your pipes or replace your valves. We have not been able to observe a loss of flow anywhere in our house, enough said about that.
The upper temperature limit is 140 degrees F. That is a difficult number to discover, but it is out there if you do your homework. Regardless, 140 is the hard upper limit in DHW mode. This is not a limitation of the unit, it is a safety limitation to minimize the chance of someone scalding themselves, and EcoSmart states this all across their web pages.
Here's the undocumented stuff:
EcoSmart supports hot water heating, and even provides plumbing diagrams. However, they will not tell you how to get 160 or 180 degree water. There are internal jumpers in the heater that allow you to limit the maximum output temperature to 105 degrees (handy for the elderly or where there are small children playing with the knob), and it is also possible to set a wattage limit across the 3 heating elements. The factory setting is 9KW per element, and 140 degrees max. output. At the very top of the jumper strip is one marked "180". With power removed, place a jumper on these two pins and the unit will allow a setpoint of up to 180 degrees when power is restored.
Most hot water heating systems operate best in the 160 degree area, and the older oil fired boilers actually used a setpoint of 200 degrees. Clearly, a heater with an upper limit of 140 degrees could cause poor performance of most baseboard hot water systems, and many of the newer hydronic systems. We replaced an antique oil fired boiler with the ECO27, and placed the setpoint at 160 to get started. The performance is nothing short of amazing, and I've actually dropped the setpoint to 150 until we get into the dead of winter. It is very nice to know that we have a reserve available.
EcoSmart provides a wealth of information about the capability of this unit. I see over and over again that people can't (or won't) get their heads around a lot of what's commonly available. Simply, if you need 4 GPM, the best this unit can do is heat the water by 46 degrees. In other words, if you want a 110 degree shower (at a ridiculous 4 GPM), you must have incoming water of at least 64 degrees. If you live in an area where your water source is about 50 degrees, you will get 96 degree showers at 4 GPM. The obvious solution is to spend $20 and get a low-flow shower head. At 3 GPM this unit can give you a 110 degree shower with incoming water of only 49 degrees. At 2 GPM this unit will provide the full 140 degree setpoint with 50 degree incoming water.
In boiler service, obtaining 160 degree water will require incoming water of at least 114 degrees. Most hot water heating systems operate with a differential of less than 20 degrees, so this unit is just loafing along while providing 160 degree water to your baseboard units. Also, most standard hot water heating systems have a design of either 1 GPM or 4 GPM. The temperature rise chart from EcoSmart demonstrates that a temperature rise of 184 degrees is possible at 1 GPM. Again, most hot water systems operate with a differential (or "Delta-T") of around 17 degrees, often less. The actual temperature setpoint isn't the focus as much as being able to maintain the differential is. So for a 180 degree output, we need to feed the heater with 163 degree water. At a mere 17 degree rise, this heater can easily flow well beyond 6 GPM, probably closer to 10 GPM, but we only need a max. of 4 GPM. So for boiler service, it is a perfect solution. It is small, silent and smart.
If you're considering this unit for hot water baseboard or hydronic service, it is capable of 92,000 BTU/hr.
It has been incorrectly represented that this is the largest electric tankless available. The largest commonly available electric tankless is 36KW. Just to set the record straight.
Overall, I give this unit 5 stars. Price, reliability and technical support are right up there. The unit comes with a lifetime warranty when professionally installed. Cleaning and maintenance is accomplished with a Phillips screwdriver, no more pipe wrenches and fiberglass insulation to contend with. The unit is so small and lightweight that I actually carried it into the house under one arm, installed it and said nothing. Nobody knew that I'd done this until days later!
The unit supports a remote thermostat which is very inexpensive and is waterproof. The little remote connects with telephone wire and is perfect for a location next to your sink or shower.
We are a 3 adult household, using all of the "normal" things, doing laundry, taking showers, washing dishes, etc. I have been able to purposely cause the heater to fail to keep up, and that was by running the tub wide open. In any other situation, two showers at once, someone in the shower, someone else doing laundry, etc., I have yet to hear a single complaint. All I ever hear is how wonderful it is to have a long shower, or not have to wait 1/2 hour, etc. The days of my wife complaining about no hot water for the dishes because I took a long shower have ended!
This is a true, self-modulating unit. People that have reported lights flickering and their TV having problems need to look at their house wiring. The unit starts softly, just like turning up a light dimmer. There are no flashing lights in this household. The only way I've ever been able to tell if the unit is running is to actually look at it - The display is only lighted when the unit is operating.
Not to be overlooked is the energy savings. A tank heater will cycle 24/7, to maintain a tank full of hot water, even if you're on vacation. The tankless does absolutely nothing unless it detects water flow. Through an intelligent design EcoSmart units ignore faucet drips and won't send hot water to drippy faucets. The minimum flow to start the unit is 1/4 GPM.
Hope this helps to quash some bad information and get accurate information posted.