Combi boiler to electric water heater

hhh2712787

Hi everyone
I currently have a oil boiler beckett wsv for the radiators and hot water I would like to separate the water and will be getting a electric water heater/tank. I was thinking to just take the cold water supply line and hot water supply line from the oil boiler and connect to the electric does that sound about right what should I do about the electronics on the oil boiler thermostat. Or is it better to have oil boiler still connected just as a back up.

Big Ed_4

Do you want hotter or volume of hot water ? Do you care to use two fuels or one or the other ?

hhh2712787

Hi Big Ed
I would rather use only electricity in the house but there is not enough power coming to the house to power everything and also I could not find any other option for the water baseboard heaters except to keep the combi oil boiler which only be used slightly in winter I had mini splits installed as well.

Larry Weingarten

Hi, I’m wondering if a 120 volt heat pump water heater could be a good fit, and meet your needs. 🤔

Yours, Larry

hhh2712787

Currently I purchased the rheem smart water heater 50 gallon 5000/5500 watt. I am planning to just remove the cold water line and hot water line from the current boiler to the new electric water heater but since I will still be using the old boiler for the water baseboards should I just plug the line that I cut or remove the coil from the boiler

HVACNUT

Leave the coil and pipe the new water heater in parallel. Valve off the hot and cold on the coil and water heater separately so if the electric water heater goes down for some reason, close 2 valves, open 2 valves and you have hot water again. 
While drawing from the electric in summer, you can turn the boiler aquastat down to 150° High, 130° Low. It'll maintain the low setting. 
150° might be fine for winter as well. On real cold days you might need to raise it.

hhh2712787

Hi HvacNut
I was thinking of doing that but would probably just shut off the boiler completely and turn on in winter if baseboard heat is needed. Can I turn on the boiler for the radiators even though the water tank will be empty in the boiler. I know the radiators are a closed loop heating system but does it effect boiler if I only use the optional tankless heater coil.

Jamie Hall

I don;t think it's a Beckett boiler. I think iit's a Peerless, likely with a Beckett burner. I also don't think tht it's combi, but it may well have a domestic hot water coil.

Can you clarify? How the domestic hot water is handled is quite different for combis and coils.

hhh2712787

Hi Jamie Hall
I will attach a picture

hhh2712787

My plan is to cut the return and supply lines from the pictured boiler and connect to the electric water heater. But I still need the boiler for the radiators in winter only. Should I plug the return and supply lines or just leave them open, and will I be fine if I start the boiler in winter just for the baseboards. Also what should I do with the thermostat just disconnect it

Big Ed_4

Agree, I would pipe in parallel and leave the coil shut . Just as a back up ..

Drop the low side of the thermostat ( triple aquastat ) down , I would leave around 100* and bring the diff up to 30*

HVACNUT

hhh2712787 said:

My plan is to cut the return and supply lines from the pictured boiler and connect to the electric water heater. But I still need the boiler for the radiators in winter only. Should I plug the return and supply lines or just leave them open, and will I be fine if I start the boiler in winter just for the baseboards. Also what should I do with the thermostat just disconnect it

If you're eliminating the coil, you can plug or cap one side but leave the other open to the atmosphere. There will be standing water in the coil and you don't want it to make steam pressure. 

Read the manual for the Hydrostat and you can set it up for cold start and use the economy setting. 

You shouldn't need to disconnect any thermostat. What are you talking about there?

random12345

There was another post about this recently. @hhh2712787 Have you done the math on this? What are your electric, gas (if applicable) rates and heating oil price/gallon? Where are you located? If this is to save money, I'm not sure it'll pay off, unless your hot water usage is very high and/or many people living under one roof. If it's for environmental reasons, I think it's possible you end up doing more damage not less.

hhh2712787

Hi Random12345
I am located in NY currently getting solar panels installed alot of extra power to make sure the whole house is powered by it I want to stop using oil but still need the water baseboards so getting a electric water heater will basically be powered free instead of using oil. What is confusing me is steps to transfer dhw to electric heater.is it as below
Drain the boiler
Cut the return and supply lines transfer to new heater and plug 1 end and leave the other end open. And in winter just start the boiler and radiators should work fine.

Jamie Hall

Unless you have a really big solar array and an even bigger battery, you're not going to get that water heater powered "free". Not happening. You might have a chance with a heat pump hybrid water heater -- but even then you are going to need a very big battery. Do your sums. Or plan on cold showers or the grid to bail you out.

Hot_water_fan

@Jamie Hall most everyone with solar stays connected to the grid…

hhh2712787

I will be getting 30 panels produce 400 watts each for a 2000sq ft house which faces south. Should be able to do the trick.

Jamie Hall

Wha happens at night?

Jamie Hall

Hot_water_fan said:

@Jamie Hall most everyone with solar stays connected to the grid…

I know that. My take is -- if you're going to talk the talk, walk the walk. And very very few people do.

random12345

Wait a second, @hhh2712787 are you saying this house is completely off-grid? You said before there's not enough power coming to the house to power everything...Either the house is connected or it isn't right?

Larry Weingarten

Hi, I think @Hot_water_fan is correct and most people use the grid as their battery. More people seem to be putting in a battery, but only if they are concerned about power outages. At night, the grid feeds power. With luck the meter just goes back and forth and usage balances production. Luck is useful 😉 And it changes things if the house is off-grid!

Yours, Larry

hhh2712787

Exactly the grid is the battery the power I get from the panels if I don't use it it gets sent to the electric company and I get credit and the cloudy days which I don't get enough power from the solar panels I get electricity from the Company and use my credits. 

hhh2712787

If I had batteries I would have been completely off the grid and would have helped if there were outages but in the past 8 years never once was there an outage so I did not get batteries not worth spending thousands to have power in a scenario that might never happen.

Hot_water_fan

I know that. My take is -- if you're going to talk the talk, walk the walk. And very very few people do.

This is your opinion, not advice for the OP. I think staying connected is fine!  

pecmsg

hhh2712787 said:

I will be getting 30 panels produce 400 watts each for a 2000sq ft house which faces south. Should be able to do the trick.

SHOULD?

No Way!

Jamie Hall

The concept of using the grid as a "battery" is very common. Except, of course, it isn't a battery. When your solar panels aren't producing power, but you are using power, the power you are using isn't coming (with rare exceptions) from power you produced earlier, it's coming from a power plant somewhere. Most folks here on the Wall are probably well enough educated to realise this, but an astonishing number of the general public are not.

I won't get into the ethics of forcing people who can't afford to put up a PV array to pay for the ones put up by those who can afford to. Think about it.

I'll give two examples, though, of walking the walk., one of which is grid connected, the other not. The first is my brother-in-law's wife. She has a Prius Prime plug in hybrid. She decided to include a solar array on the roof of her garage which is used to charge the Prius. It is NOT used to power anything else in the house, and doesn't have the capacity to. The second is a resort island off Portsmouth, NH. Five miles off. Grid connection would be... difficult. It gets all its power from a very large PV array. Some compromises were made -- there's no heat in any of the buildings, and hot water (hybrid heat pump water heaters) is strictly rationed, for instance, but it honestly does get all its power from that array and the associated battery banks.

Oh and one other thing -- that big array mentioned above, for those who like numbers, will save the owner a whopping one gallon of oil per day, on the average.

ethicalpaul

> I won't get into the ethics of forcing people who can't afford to put up a PV array to pay for the ones put up by those who can afford to.

We force people who can't afford it to pay for the military, road subsidies, oil industry subsidies, states who pay less in taxes than they take from the US, and the ability for real estate professionals to only pay 15% income tax, and on and on.

And yes, some for installations of renewable resources. No ethical problems with all those other ones?

Hot_water_fan

@pecmsg I think they mean for the DHW, in which case a 12kw should be more than enough. 

Hot_water_fan

I won't get into the ethics of forcing people who can't afford to put up a PV array to pay for the ones put up by those who can afford to. Think about it.

So get your state’s net metering reimbursements lowered! The electricity has value. It seems like you are just upset with the price. What if the net metering price is lower than rooftop solar’s value? 

hhh2712787

I think I will connect the electric water heater turn the boiler off completely and see if I even need the baseboards if not after this winter I will remove boiler completely if anyone is interested it is 6 years old like new 

Hot_water_fan

I think I will connect the electric water heater turn the boiler off completely and see if I even need the baseboards if not after this winter I will remove boiler completely if anyone is interested it is 6 years old like new

Oh. You're planning to use an electric tank heater for central heating? I interpreted your question as just related to domestic hot water.

I recommend pro to sort this out - there's a lot of details you need to get right.

hhh2712787

No I am not using hot water heater for heat not possible my boiler was providing dhw and heat for my water baseboards I am moving dhw to a electric water heater and completely power off boiler and see if I even need the water baseboards.

Jamie Hall

If you want some idea where I'm coming from on ethics, go read some of the writings of a former professor of mine, Rheinhold Niebuhr (might start with On Politics). The Wall is not the place for such discussions.

ethicalpaul

Respectfully my friend you brought the discussion to the wall by claiming you weren't going to mention it, yet making your point about it anyway But I will agree to end it and will go look for his book too--the philosophy of ethics is a pet topic of mine, thanks

hhh2712787

Hey everyone
This discussion is moving in the wrong direction. Everyone is right in there own perspective. Is someone able to help me you if I have the peerless system boiler for heating and for dhw and I only want to use it for heating is it as easy as just cutting the return and supply lines or is there mire to it.

ethicalpaul

Yes, do what you described in your first post...cut it and cap one end is fine (I'm not even sure what purpose capping one end does but it won't hurt to cap only one).

hhh2712787

Thank you ethical paul

pecmsg

Hot_water_fan said:

@pecmsg I think they mean for the DHW, in which case a 12kw should be more than enough. 

Maybe

Maybe not!

Jamie Hall

Well, it should be, @pecmsg -- those things only draw 4500 watts. Assuming that the inverter can handle the load (it's 240 volts at a bit under 30 amps) and the sun is shining. If it's grid connected at the same time, though, as well, it shouldn't matter.

john123

I am having a little difficulty following all this.

You say you have limited Electric power and that's why you have the oil boiler to heat the rads in the winter
but don't need it too often.

And you have put in an electric tank (which uses a fair bit of juice)--perhaps slightly more so in the winter when the input cold water is a little colder.

In the winter at least, why would the OP not want to pre-heat the DHW in the coil and then send it as the input to your electric hot water tank--kind of on-demand as you use the hot water? OP is not going to burn any oil unless the DHW is demanded. The electric tank would always try to maintain the water temp in the tank as OP has set it. But OP would not use as much electricity doing so as OP would if the tank were alone responsible to heat the DHW.?

The main thing is that OP would have substantially more hot water as those electric tanks are not quick to re-load; In the Winter, it's one shower and done sometimes. OP will usually have to wait a couple of hours to take a second shower. The water coming in at a high temperature would give the electric tank a head start.

I am little new here ---maybe it has something to do with pressure drop????

Robert_25

hhh2712787 said:

Hi everyone
I currently have a oil boiler beckett wsv for the radiators and hot water I would like to separate the water and will be getting a electric water heater/tank. I was thinking to just take the cold water supply line and hot water supply line from the oil boiler and connect to the electric does that sound about right what should I do about the electronics on the oil boiler thermostat. Or is it better to have oil boiler still connected just as a back up.

You will need to disconnect the domestic water piping from the coil as the guys noted above, and turn down (until it says OFF) the low limit setting in the aquastat (digital control in your picture). This will make your boiler "cold start", meaning it will only turn on when something is calling for heat, rather than staying hot all the time.