Heating with Water Heater (2)

Nick_16

Hi all! I wrote in before Christmas asking about using an electric water heater for space heating rather than a boiler. Most people suggested that I wire it so both elements come on at the same time. This sounds like a good idea to me. How do I go about doing this? Also, how do you figure out the "amount of head" and how to size your circulator pump. Thanks all!

Glen

slow down for a moment -

While I understand the rationale behind this thinking - consult with a qualified electrical contracter first. Your water heater and the related wiring to it is probably certified for alternate element uasage - which means that - if you fire up both elements your wiring is probably too small. The potential to harm you and your family is great. Make sure your cable size is correct for the new load and the breaker can handle it as well.

Dale

Take Glens advice

Most elect heaters are 5500 watts max. total load. Most do this by non-simultaneous operation. The reason for this is this is what the wiring, and ECO are rated for. Also this is the max you can load #10 wire feed to a water heater per elect code. Also switching on more that this requires staging like an electric furnace so you don't brown out yourself and what ever other neighbors share your utility transformer. Whatever you decide make sure the wiring looks like one of the elect. water heater manuf. drawings. It can be done but an ECO must be on the tank upstream of all elements. If you are willing to stay at 5500w or less then it's pretty simple, just follow the wiring drawing that shows simultaneous operation for your heater.

hr

Hire a sparky!

Basically you need to run two seperate 30 amp circuits (#10 wire)to run both 5500W elements at the same time.

I use a complete upper HW control WITH the reset button, to control the bottom element at the same time. So the top and bottom element each have a seperate reset and temperature control.

I like to fish the second circuit, #10 wire, down to the lower element. That way each element has a seperate circuit, on seperate breakers.

Make sure you label the tank with a magic marker that it is fed by two circuits! This way the next person to work on it will be aware that two breakers need to be disconnected before servicing.

hot rod

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freon12

hot rod knows how


look on name plate and divide watts and volts and you get the amp draw of each element ie 4500 / 240 = 18.75 amps per element

Eww maybe you can wire in an outdoor reset on the 2nd element (grin)

hr

I have run 4500 watt

elements on a 20 amp breaker. IF you are sure you have 240 volt or more.

4500 watt divided by 220 V = 20.45 amp draw

You could drop to 4000 watt elements and stay comfortably within a 20 amp #12 wire circuit.

Actually most electric water heaters are wired with #12 wire from the junction box down to the controls and element. Not sure how that meets code, when connected to a 30 amp breaker??

hot rod

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freon12

could be the varoius voltages 240/230/220/208 and how they vary daily...as far as the breaker maybe thats why hw heaters have internal circuit breakers? #12 wire is rated for 25 amps.
I think the codes keep changing for the manufactures but not the installers. I ran into a situation when all the equipment had 220 coils on the contactors and the local codes would only allow us to wire control voltages at 24 or 110 volt
Best I ever saw was a control panel with 460 volt coils "yikes"

Dale

Water heaters and the NEC

HR, you might want to look at 422-14 (b) saying that the branch circuit rating needs to be not less than 125% of the nameplate rating. They figure the WH to be continously powered. This is why the install instructions that come with the heaters show a larger wire size that the math would come up with. The NEC ends at the heater connections so the installer wonders why he's connecting #10 wire from the panel to #14 wire in the heater, the heater mfg only needs to test the wire temp for the short length of what's in the heater. As to the breaker or fuse size the exceptions seems to say 100% of load if rated for it.