We are currently bidding on a job for a building where there will be commercial space on the first floor and four apartments above. Specs call for three of the four apartments to get EEmax HA036240 water heaters. Manufacturer specs call for each unit to fed by 4- 2 pole 40 amp breakers. These apartments are all electric as there is no gas on the street and no room for LP tanks on the property. Each unit will have it's own 200 amp panel. Does anyone have experience with these water heaters? I'm afraid the service is undersized...
On Demand Electric Water Heaters
- Thread starter T. See
- Start date
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Welcome to the forum.
You are correct; you don't have enough power for all of that plus a tankless WH.
I have added a second 200a service panel just for one with four 40a 2p circuits.
One advantage of a second 240v-only panel is that it need not have a neutral.
Just for fun, do you have load calcs for each unit? Was a tanked WH included?
You are correct; you don't have enough power for all of that plus a tankless WH.
I have added a second 200a service panel just for one with four 40a 2p circuits.
One advantage of a second 240v-only panel is that it need not have a neutral.
Just for fun, do you have load calcs for each unit? Was a tanked WH included?
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
Heat pump water heaters?
Eddie702
Licensed Electrician
- Location
- Western Massachusetts
- Occupation
- Electrician
Each of those heaters is 36kw at 240 volt (150 amp) or 26.6 at 208 volt. Tell them you need to use tank type water heaters. 1 30Amp two pole/apartment.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
The bottom line is that each unit would need a 400/320a service and two panels.
Do you by any chance have 3-phase available?
Do you by any chance have 3-phase available?
We just had the utility out to look at the property. It would be prohibitively expensive to bring in three phase. The building will have a 1000 amp 120/240 service.The bottom line is that each unit would need a 400/320a service and two panels.
Do you by any chance have 3-phase available?
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
A-men, it baffles me that people use those things. Elec tanks have very low losses because the whole unit is encased in foam (unlike gas tank units), low capital cost, low installation cost, unlikely to have problems or require maintenance. If people are concerned about running out of hot water, get one of these that that have bigger tanks and/or can be configured for 12kw.
80-Gallon Light-Service Commercial Electric Water Heater | A.O. Smith
Looking for high-quality water heating solution? Review the 80-Gallon Light-Service Commercial Electric Water Heater from A.O. Smith.
www.hotwater.com
Eddie702
Licensed Electrician
- Location
- Western Massachusetts
- Occupation
- Electrician
I agree. When I go on vacation I kill the electric hot water heater and shut the water off coming in the house in case something let's go.A-men, it baffles me that people use those things. Elec tanks have very low losses because the whole unit is encased in foam (unlike gas tank units), low capital cost, low installation cost, unlikely to have problems or require maintenance. If people are concerned about running out of hot water, get one of these that that have bigger tanks and/or can be configured for 12kw.
80-Gallon Light-Service Commercial Electric Water Heater | A.O. Smith
Looking for high-quality water heating solution? Review the 80-Gallon Light-Service Commercial Electric Water Heater from A.O. Smith.
I have been gone 12-14 days and come back and the water is still warm. Of course, that was in the summer. When I go to Florida for two week this coming February, I am sure it will lose temp.
Anyone that I know that had a tankless had issues with it.
Fred B
Senior Member
- Location
- Upstate, NY
- Occupation
- Electrician
If you are looking for efficiency overall, the heat pump tank water heater is the best bet. Comparable cost to tankless but no where near the power requirements, and 2 less breakers and overall amperage requirement. I would never recommend electric on demand anywhere north of Florida, the temperature lift required way to large for the typical 40-50 degree water coming into the WH forcing a way higher electrical load to get a usable hot water. Gas on demand a whole different thing (but you indicate not doable).
My Guess it's Way undersized, have you done an actual load calculation, total and per unit? Also Tenets will never be happy with the Hot water provided or, if separately metered, the Cost.
Knightryder12
Senior Member
- Location
- Clearwater, FL - USA
- Occupation
- Sr. Electrical Designer/Project Manager
Is there an EE involved with this project or are you designing it? If its an EE, it would be time for an RFI (Request for Information) to him. If it was designed by an EE there should be load calc's on the plans. What does the plans show?
The problem with these is the amount of cold air they generate. These too would be good in a hot climate and if put in the garage would help keep it cool whereas garages aren't normally conditioned spaces. But in an interior room in a heating climate, these don't seem like a good idea either unless they have heat pump water heaters that duct the cold air outside.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
First: There are split heat pump water heaters, with an outside unit like a minisplit.
Second: 3 of the apartments get these 36kW beasts. What do the other spaces get?
Third: If each apartment has a 200A service, then IMHO you have a problem. Running this 36kW water heater plus a couple of other loads could easily exceed 200A. But if the building has a 1000A service with feeders to the various loads, there is a good chance this will be fine.
Load diversity is your friend, and these heaters modulate. To see full power being used, you need to have full water flow. What is the chance that everyone in the several apartments is having a shower, running laundry, and washing hands at the same time?
Jon
Second: 3 of the apartments get these 36kW beasts. What do the other spaces get?
Third: If each apartment has a 200A service, then IMHO you have a problem. Running this 36kW water heater plus a couple of other loads could easily exceed 200A. But if the building has a 1000A service with feeders to the various loads, there is a good chance this will be fine.
Load diversity is your friend, and these heaters modulate. To see full power being used, you need to have full water flow. What is the chance that everyone in the several apartments is having a shower, running laundry, and washing hands at the same time?
Jon
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Greentagger
Senior Member
- Location
- Texas
- Occupation
- Master Electrician, Electrical Inspector
Unless I misunderstood, a (grounded conductor) neutral will be required if service panel. 250.24(C).
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
I'm aware of only one make, which is Sanco. (formerly Sanden, iirc). Curious if you or anyone knows of others.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
He's talking about a separate subpanel on the load side of the service panel. You are correct that the neutral must be brought to the service equipment. He is correct that it doesn't need to be brought further to a subpanel if not used there.
Joe.B
Senior Member
- Location
- Myrtletown Ca
- Occupation
- Building Inspector
Heat Pump Water Heaters – Columbia River PUD
www.crpud.net
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I have a propane fed tankless and am very satisfied with it. The cost of propane here means that the cost is about equal to resistance electric heat. But I would never use an electric tankless. The increased peak load on the infrastructure combined with the uneveness of renewable energy will just make the necessary infrastructure improvements that much harder.
For carbon footprint consideration, the heat pump is the only way to go. But that will never support tankless, IMHO.
For carbon footprint consideration, the heat pump is the only way to go. But that will never support tankless, IMHO.
Yea electric tankless never made any sense to me. A 50 F rise = 28 C rise. Just a single 2.5 GPM shower head = .16 liters per second. So (.16 liters) x (4,200 joules per degree) x (28 degree rise) = 18,500 joules per second (i.e., 18.5 KW). For one shower head assuming 100% heater efficiency.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Definitely not something you want to use when you are on a generator.
All-
I've been away for a few days and haven't had access to a computer. Thank you all for your responses. Great stuff here as always.
We've been trying to tell this designer that this wasn't going to work for months. Originally there was no EE involved until we suggested they might want to hire one. And what do you think they said?
Thank You All
I've been away for a few days and haven't had access to a computer. Thank you all for your responses. Great stuff here as always.
We've been trying to tell this designer that this wasn't going to work for months. Originally there was no EE involved until we suggested they might want to hire one. And what do you think they said?
Thank You All