Tankless Heater Problems And Reviews

Question: I want to replace my water heater - 2 x 30 amp breakers. the tankless heater says it needs 120 amps. how ?

(Posted by: R H on 2008-10-25 19:54:52)

The tankless says it needs Technical Specifications: * Volts: 240/ 208v * Kilowatts: 26.85/ 20 kW * Amps: 120A (3x40 amps) * Efficiency: 95 Percent * Water Fittings: 3/ 4 " male NPT * Wire Size: Minimum #8 AWG (6 conductors & ground) How can I do this?

Posted by: Rich Z on 2008-10-25, 20:09:00

As in the section you quoted you need three 40 amp breakers ( "3x40 "). That is equivalent to what an electric range needs..

Posted by: Widget Maker on 2008-10-25, 20:14:03

Looks like three 40 amp circuits at 240 volts. You will likely have to install #8 AWG wiring for a second and third circuit. You will have to ensure that the other circuit already in place is #8 AWG. It is possible that lower capacity wiring was used with your 30 A breakers. Since it is 240 volts you will need 6 breakers, two for each circuit. I think you may be overloading the electrical capacity in your house. Most houses have 120 Amp or 200 Amp service that is meant to be sufficient for the peak electric load. By installing 120A equipment in place of 30A equipment there is a good chance you don't have the right capacity in your house. May I recommend hiring an electrician? Insurance matters, home safety, and permit matters apply.

Posted by: "33" on 2008-10-25, 20:20:20

You would need to call an electrician. If you wire this on a 2 pole breaker you'd need a 125A breaker. This might require a heavy-up. If you wire this on a 3-pole breaker, though I doubt you have a 3 phase service, you fuse it significantly lower. Still, call an electrician as there are other factors that may need consideration. Wish I could help more, but I'm without my codebook.

Posted by: }}}~~~~> on 2008-10-25, 20:40:10

You will first need to make sure that you have at the very least a 200A electrical service coming in. If you do not, forget it. If you do have a 200A service then you can do a load calculation to determine the load for the square footage of your house and the connected appliances. This takes time and data collection. You have a single 2 pole 30A now (or some idiot used two single pole breakers). You would need 3 times the space in your panel that you are currently using. It may be possible to use 1/ 2 space breakers however. What is the make of your panel? What is the year of construction of the electrical service? What is the square footage of your house? There is a >90% chance that you will not be able to install an electric tankless water heater in a house that wasn't designed for it without changing the service, and there is a really good chance that a 200A service isn't even big enough. Sorry, that's the breaks. You might consider a gas fired tankless water heater.

Posted by: neogeek79 on 2008-10-25, 22:26:29

This electric tankless water heater requires a three phase service. you do not have this in your home. electric tankless water heaters are not practical for use in residential applications. if you do not have propane or natural gas service, you're better off using a tank electric water heater like what you had before.

Posted by: Electrical Inspector on 2008-10-26, 00:34:16

240/ 208 Volts is generally a three phase service, and not available to residential construction in most areas. If your current water heater is using two 30 Ampere breakers, I would wonder about the qualifications of the person who installed them. Hire a qualified, licensed electrical contractor to replace the two separate breakers with a double pole breaker listed and approved for use in your panel (and, to check that the mope who installed two single pole breakers knew enough to use the correct size conductors in the first place). Also, if the heater says it requires "Technical Specifications ", where are they? The listing of a product requires that the specifications and installation instructions be included with the product, as they are part of the listing and labeling of the appliance. I would be willing to bet that that this heater is not listed to US Standards. More than likely the only Listing Agency Marks you will find on the unit will be "CSA " or "UL-C "; both are Canadian listings. Also, be very wary of the "Mini " breakers. Most manufacturers limit the number and the locations they are allowed to be installed in a panel. Some panels do not allow them to be installed at all. Check the door or front cover of your panel to see a complete list of what circuit breakers you can install in it. Using a breaker not approved by the manufacturer will void the listing on the panel; which could present very big problems should you ever have any type of electrical problems [including the very real possibility of a fire when listed equipment or parts are not installed according to their instructions -see NEC 110.3 (B)]. You should never use the “Mini� breakers on a three-wire “network�, as you could easily overheat the grounded (neutral) conductor by having it carry the current from the same leg of your panel. When a neutral is shared, it must be used with one circuit fed from the “A� leg, and one fed by the “B� leg.