OK, So I had a weird setup, 2 boilers each with a hot water heater coil. Each boiler had has 1 zone for forced hot water. They work together though for all hot water domestic needs. We are going to be renting out both units in the duplex so we separated the domestic hot water lines. Neither coil is able to keep up with hot water demand for a shower. Hot for a minute and then luke warm water. One unit is old (15 to 20) and the other is a dinosaur (60's huge cast iron sunrise or something brand). I assume I shouldn't even be talking about replacing the coils on such old machines. They both have 82% efficiency at the moment. Unless the coils would be usable on a new boiler when I have to upgrade in future. Should I just go with electric water heaters for each apartment, they have their own service and their own oil tanks. Thinking 120v 40 gal for each of the units, 1 is a 1 bedroom, the other is a 3 bedroom. Is this likely adequate? Also, how may amps do these draw? Each apartment has 100 amps service and they currently have electric stove/ fridge, and clothes dryer. Window a/c's in summer. Don't think I can afford to replace both boilers right now. If I do replace boilers should I consider converting everything to propane? Can plumbers do wiring for electric water heater or do I need 2 companies? Thanks

Hi Libenitz

Forget 120V for a 40 gallon or larger electric water heater...these all take 220-240V. Next, you'll need a 60 gallon (at a minimum) for that 3 bedroom and should probably just install a 50 or 60 gallon for the one bedroom as electric water heaters do NOT recover very quickly and will prove to be a headache for you if you don't set things up properly from the start...;)

Electric water heaters use a 30 amp double pole breaker, so it sounds like you are near the limits here (100 amp service).

A plumber installs the water heater(s). A permit should be pulled and the work inspected by a local plumbing inspector (in most states).

An electrician would be required to install the new wiring. A permit should be pulled and the work inspected by a local inspector. An electric TIMER for each water heater may be a good idea to cut down on costs a bit, but that will depend on your electricity costs and any special programs the electric company may have (consult electric company to see if they have special peak VS off peak use programs).

Finally, I can't speak to the boilers...would need to have a local heat person come in for that. Propane may be a good idea for heating water, but again, talk to your local people on that, OK?

You may also want to consider TANKLESS water heaters here, but once again, installing these is something that is very specific to your weather conditions all year round...;)

Lots to consider here, like power vent VS direct vent VS natural draft (chimney) VS required chimney liner (or not) if you want to use propane, so start to investigate this if you intend to call someone in. This will allow a better conversation for both of you!

Good luck!

Mark

Should have mentioned:
I live in NH. I think I was told a while back that a plumber is allowed to wire the electric water heaters. I would certainly think any plumber out of the phone book would require a permit, no? I would want it for my own protection to make sure they did the work properly.
Really appreciate the insight Mark, FWIW I have the 2 boilers going into a chimney. Should I have put this in the heating (as opposed to plumbing) section?
Lastly, do those tankless water heaters go off oil? I thought I read that the electric ones can't really keep up with demand and they may overload the electric panels, I'll have to call an electro for the consultation on power availability.

I'm going to get in trouble for this but I think I am going to disagree with Mark.

While a water heater is wired for 30 amps it only pulls 19 amps. Typical electric dryer will pull about 25. Stove, depending on size, can pull as much as 50 amps, but that is with all elements and the oven going at the same time. Unless you are running a restaurant, who does that.

I think you will be all right with the 100 amp service. If you find that the main does occasionally trip, change the elements of the water heater to 3500 watts. That would increase the recovery time but would lower its draw to 14.5 amps.


I live in NH. I think I was told a while back that a plumber is allowed to wire the electric water heaters
I believe the same is true for Virginia.

What fuels the boilers? Unless you are heating with oil or wood you could consider a gas water heater.

No disagreement, Harold...just cutting close was all I was thinking!

In terms of a plumber wiring anything in NH, no plumber is allowed to wire anything in any state that I know of....different insurance requirements and schooling so it is NOT accepted anywhere. A quick call to a local plumbing inspector will confirm this!

Most of the plumbers here are also heat technicians, so no worries there. Heating and converting is simply not something that can be reasonably dealt with online. Here, we can advise you a bit, especially on questions and things you can/want to consider, but we cannot say anything with absolutes as we are NOT on the job and cannot see anything. The final answers will come by pulling in 2 or 3 local plumbing/heating contactors and getting their thoughts, OK?

Mark

Mark, Harold, I've learned a lot just from your answers. It sounds like I can't run propane around an oil environment? Is that why I can't use propane? Because that could solve the problem by 1) getting away from putting new water coils in old boilers and 2) not pushing the limits of the electrical service. Upgrading the amps from the street would be very expensive because I'd have to replace the breaker panel and everything in it.

Harold is correct that 100AMP should be fine (and he knows tons more electrically than me), so that really isn't the concern on electric. Electric seems like a very reasonable answer here.

In terms of propane use, many towns/states will not allow homes to have two fuel sources in the home...not on upgrades anyway, so that may be the issue. Also, chimneys with oil appliances cannot usually have propane or natural gas connect into them nowadays. Here, there have been MANY code changes over the last few years, and that is why I say that you really need to talk with local people on such a big job. We can offer experience and thoughts, but can also aggravate and cause problems if we get your hopes up only to find that your local inspector wants something completely different, right?

So I had the electro in today and the plumber. They said there is plenty of amps available and that they can do the work in a few hours. They said go wtr heaters and get off the coil because they aren't universal and I will likely need to buy another one when I were to replace the boiler down the road. They are thinking 40 gal for the 1 bedroom and 50 gal for the 3 bedroom (5 rooms total) units.
The electro did find that while I have 100 amp service to each panel the socket meters are 60 amp each (on the outside of house). The PSNH company replaces those meters and the drop line that feeds them along the side of the house.. no charge. He will upgrade the grounding wire and bring that component up to code as the code has updated sin the 70's apparently! Thanks for all your help guys. I feel good getting this stuff safe and up to code and not having tenants deal with crappy hot water supply. I don't want to be one of those kind of landlords. I will be back with more ?'s at some point. Like advice on replacing the boilers for the FHW heat systems, they are going to go at some point.
Thanks again.

Thank you for the update...always appreciated!