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Oil fired & electric boiler at same time? HELP

shanzzie
shanzzie Member Posts: 13
edited August 2020 in Oil Heating
We purchased a home which has both an electric & oil fired boilers. They are both hooked up to each other and we're not sure if we need to use the oil or if we can just bypass it and only use the electric.
Here's the set-up... I can take more pics if required. Let me know ...




Comments

  • STEVEusaPA
    STEVEusaPA Member Posts: 4,841
    edited August 2020
    Hard to tell, need better lighting. Something unique going on there.
    Too bad the previous homeowner can't help you.
    Looks like they probably use the electric on demand all summer, then when they put the boiler on in the fall they probably leave the electric off.
    Probably close off the valves if possible so cold water doesn't flow thru the electric.
    Unless your electric rates are low, you might find out that this doesn't save much money this way.
    Better would be to let the boiler charge the storage tank.
    ---Or---
    They have this set up to get constant hot water until the boiler's tankless coil catches up.
    steve
  • shanzzie
    shanzzie Member Posts: 13
    edited August 2020
    @STEVEusaPA

    Thank you for your reply. I should maybe mention that we are in Quebec Canada .. and unique was not the word I used when I saw this system. LOL :)
    The whole system was/is turned off, the hot water heater is independent. Only in/out water pipes are coming from it to the oil boiler.
    I took some more pics, not sure if they will help any. I've messaged the old owner to see if he can help out, but have yet to hear back from him.













    Thanks
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    A few thoughts

    your oil heater at one time has set up as a source for both heat and hot water


    Are you in an area where a fuel delivery truck may have difficulty reaching your fuel tank with excessive snow on the ground? The electric boiler may be there to keep the home from freezing up.

    I there an electric power generator on-site to use if the power fails? No Oil and No electricity with several days of deep-freeze will become costly, burst pipes, and all!
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • shanzzie
    shanzzie Member Posts: 13
    @EdTheHeaterMan
    hmm! those two pipes you have circled are coming directly from the hot water tank and are the only valves that look to be in the ON position. Other than that, the entire system is turned off (directly on the boilers & the breakers).
    The pipe next to that, with the red valve is connected to the hydra boiler and there is another pipe coming from the oil boiler going directly into the top of the electric boiler, which also leads to the Fill-Trol and also branches off to somewhere in the wall.
    Since everything is interconnected, I'm guessing that we aren't able to just use the electric boiler independently from the oil boiler.
    We do not have a generator, we are looking into getting one - just in case. It will be our first winter here, we've been here for only 2-3 weeks now and are used to forced air natural gas furnaces .. so much simpler than this spaghetti mess. :)
    Thank you for your input .. I'm hoping the former owner gets back to me to shed some light on how to use this thing. We'd like to fire it up to test it out, but the oil tank is completely empty and the fill pipe outside is in the dumbest spot .. we have an embankment where it's located. Driver would probably have to bring the pipe through the house and go out the window, or go to the neighbor below and climb up a tad.

  • hot_rod
    hot_rod Member Posts: 14,561
    edited August 2020
    That is a common setup in your area to take advantage of extremely low electric rates. Some systems have automated switch over. It Is based on power plant production vs loads, not a time of day schedule
    depending on which plan you chose it drops to something like $.06 per kWh
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • shanzzie
    shanzzie Member Posts: 13
    @EdTheHeaterMan
    The area you have circled is directly connected to the hot water tank. Those look to be the only 2 valves in the ON position. Everything else is in the Off position, both boilers are off (switch & breakers) As for filling the oil tank, the fill pipe is outside my living room window, the only issue for safety I see is the fact that they put it where the embankment is - which I do think would be dangerous anytime of the year.
    We do not have a generator, but are looking into purchasing, just in case.
    There is a pipe coming from the oil boiler going directly to the Hydra - and a pipe below coming from the Hydra to the location you have circled in the pic.
    I'm guessing that we wouldn't be able to use the electric boiler (Hydra 20KW) independently from the oil boiler.

    @hot_rod yes, very popular here. My grandparents and my father had a similar set-up up north. Oil would kick on after x degrees and off once the weather warmed again and go back to electric. But both of them had forced air furnaces.
    We were wondering if we could use the Hydra electric boiler independently from the oil. Or do we have to use both because of them being connected together.
    We would like to turn them on to ensure they are working, but my oil tank is completely empty.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    In this illustration, you will see some of the components of your system. this is not exact, but this is the best I could figure.

    The cold water enters the boiler room from the top right of the illustration. From there it should feed the boiler fill valve (not marked) and the water heater at valve B. There may also be a valve D where the cold water feeds the tankless DHW coil in the oil boiler. Valve D should be closed in the summer and open in the winter when the oil boiler is operating. Valve B should be closed in the winter when the oil boiler is operating and open in the summer when the oil boiler is off. Be sure to turn off the electricity to the water heater in the winter when the oil boiler is operating. Valve A and C should stay open all the time (except for service) to allow for pressure relief from the respective vessels.

    The heating system is feed by the fill valve to the boiler system. once the system is filled with water and properly purged of air, the numbered valves can be operated to as follows. to operate the electric boiler: turn off the oil burner switch, open valve 1, and close valve 3. To operate the oil boiler turn off the power to the electric boiler, Close valve 1, and open valve 3. The circulator pump may be operational by both systems or there may be a circulator inside the electric boiler (under the cover). The instructions are the same in either case if the wiring is done properly.

    If you are close to Hydroelectric power and your electric rates are low... you will probably use the electric boiler all the time and leave the oil boiler off. If you need to operate the heat by a generator, the oil boiler will be less expensive to operate.

    If you are not on Hydro-electric power from your utility, then oil heat may be less expensive and you will use the electric sparingly.

    @shanzzie , I hope this information is somewhat helpful


    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • shanzzie
    shanzzie Member Posts: 13
    @EdTheHeaterMan Thanks a bunch .. it does help very much.
    The electric boiler has 3 settings - Electric, Off & Oil.

    I'm guessing that if we have to switch to oil heat, we would turn off/on the valves as mentioned and flick the switch of Oil (Huile in French).
    Again, thanks a bunch .. the diagram is very helpful.
    Being so used to forced air w/natural gas .. the spaghetti pipes can be a tad intimidating.
  • vtfarmer
    vtfarmer Member Posts: 37
    Hydro Quebec used to have a residential rate where you paid something like 3 cents a kWh (several times less than most residential rates in the US and Ontario) and in exchange for this you agreed to switch your heating source to propane or oil (not wood because it had to be automatic) when the utility asked you to. Many homes in Quebec were set up for this at one time.

    I forget what this rate was called but it was in place until their new dynamic pricing program started rolling out a couple of years ago. The new program base rate is 6 cents (still very cheap!) and it goes up at certain times, which is equivalent to when you used to be signaled to switch heating fuels.

    Both the old and new rates would ask you to switch at any time that Hydro Quebec couldn't meet demand from their hydro and atomic fleet (didn't their lone nuke retire? maybe it's all hydro now), which have a super cheap, mostly fixed cost to operate. Supplying demand above and beyond what this fleet can supply can get really expensive really fast as they have to either import from adjacent systems or exercise call options on capacity from third party natural gas peaking generation in their footprint ($$$).

    So, with today's rates you may be ahead running the electric boiler most of the time depending on the cost of oil, but be sure you are signed up for and understand whatever dynamic rate they have in place today.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    edited August 2020
    You may want to double-check the DHW piping design. Some plumbers will use the tankless coil in the oil heater to preheat the water in the electric HW tank. This means the valves on the Potable water are not changed from season to season. See if this illustration is more like yours.




    This is the potable water system I originally described. This will need valve adjustments as previously described


    All heating pipes removed from diagrams to reduce confusion.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • GroundUp
    GroundUp Member Posts: 1,139
    Maybe someone already mentioned it and I missed it, but it looks to me like you'd be able to close the two blue handled gate valves on either side of the oil boiler and open the smaller red handled gate valves that go to the electric boiler and be in business. The way it's piped, the circ and air scoop would still be functioning with the electric boiler only
    EdTheHeaterMan
  • shanzzie
    shanzzie Member Posts: 13
    @vtfarmer I checked the Hydro Quebec site and they do offer a dual system with automatic switch when it hits either -12 or -15C (5-10F) with a dual energy meter, which we do not have. We would have to switch manually, we would prefer to just stick with the electric and if we find it's way too expensive, then we'll go dual the following season.
  • shanzzie
    shanzzie Member Posts: 13
    @EdTheHeaterMan I will check and get back to you. :)
  • shanzzie
    shanzzie Member Posts: 13
    @GroundUp it's exactly what we were thinking. :smiley:
  • shanzzie
    shanzzie Member Posts: 13
    edited August 2020
    @EdTheHeaterMan I wasn't quite sure which of the drawings fit best, so I took a few more pics following the main pipes, starting at the Fill-Trol to the oil heater and from the oil to the electric.
    There is a valve next to the Fill-Trol, which is currently in the off position, I'm guessing that this should be On when the boiler is running? There is also a switch for the pump, which should also be on? Is there a specific sequence to turn things on?
    Again, appreciate all the help.
























  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    edited August 2020
    OK, so I took some time to analyze your photos. The illustration is potable water only. there are no heating pipes in the diagram

    There are 2 pipes that I'm not sure where they go. They appear to be added after the oil system was installed. In the picture and illustration, I have marked them.

    Unless there is another component that changes the plan, it appears that there are 3 extra valves that make your system able to do both previous DHW diagrams. I must assume the unknown pipe is connected to the same device as a thru-put process. Maybe a heat pump, maybe a water filter, whatever it is, the water used to go straight from valve D, straight down into the tankless coil.



    The three valves are marked X, Y, & Z. Now if the valves are as follows, the oil heater only will make the DHW

    Cold water valve D open
    Cold water to mix X open
    Hot Water Valve C open
    Service Valve Z open
    Service Valve X closed
    Cold Water Valve A Closed
    Hot Water Valve B closed, then opened 1/2 turn to allow for water expansion in the electric tank.
    Turn off the power to the electric water ehater



    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    To preheat the DHW before entering the electric water heater the valves are configured as follows.
    D open
    X open
    C open
    Y closed
    A open
    B open
    Z closed
    Both the electric water heater is operating and the oil heat is operating

    The electric boiler for space heating is off (switched to oil)

    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    edited August 2020
    When the electric rate is the lowest, and the oil heat costs more. (This is the way you want to try first)

    The valves should be as follows:
    A Open
    B Open
    Y Open
    D Closed
    X open or closed (does not matter)
    C Closed then opened 1bout 10° to 15° from completely closed to allow for expansion in the boiler coil
    Z Closed


    Still want to know about the unknown pipes. I hope it is a filter

    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    Also

    This is the diagram of the heat pipes.


    The original instructions for operating oil or electric are still the same.
    Switch on electric Valve 1 & 2 are open. Valve 3 closed Valve 4 left open for expansion
    Switch on Oil Valves 3 & 4 are open. Valve 1 closed valve 2 left open for expansion.

    The small valve that feeds the boiler near the pipe that goes thru the wall can be open if the auto-fill valve is in good condition. You have a special expansion tank called a Fill-Trol. You must replace it with the same brand and model number expansion tank for the valve to work properly. If the valve fails, you might want to consider replacing both the expansion tank and the auto feeder valve with another design.

    SO... Yes you can leave the valve open when operating either heating system. Both electric and oil use the same fill water valve.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • shanzzie
    shanzzie Member Posts: 13
    @EdTheHeaterMan Wow, these are wonderful.

    The two pipes you're asking about go into the oil heater.


    One of the pipes with the black (slightly melted) wrap ties into other pipes at the top.








  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    edited August 2020
    OK, The only reason that I can think of doing that to the cold water inlet pipe is to preheat the cold water prior to entering the tankless coil. Since you are located near the Arctic Circle (Haha just kidding) your groundwater entering temperature might be rather low. The entering temperature of 14°C can be heated to 46°C or higher in NJ and maintain a constant temperature for an unlimited, time when I'm in the shower, using the tankless coil. If your entering water temperature is closer to 8° or 10° then your shower might not be so comfortable. I like a HOT Shower!

    So the previous owner may have encountered that problem. To resolve, someone cut the cold water pipe near the tankless coil, opened up the rear panel of the heater, placed the cold water pipe near the steel boiler (that stays hot all the time to maintain DHW temperature) then routed the pipe back to the cold inlet of the tankless coil. Then he put the insulation over the pipe and covered up the pipe and boiler, then put the rear panel back on.

    Pretty clever. IMO!

    So, now that I'm sure of the piping, you may want to put labels on all the valves, copy these instructions, laminate them and hang near the boiler.

    Off topic but related to labels...
    I had a brother in law that had a problem with purging the air from his system and a plumber would charge him Big$ to do a simple job. I labeled his valves and gave him instructions on how to do it. I could talk him thru it, over the phone because I knew what each valve did. Never paid a plumber after that.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    It also appears that you have 2 zones (2 thermostats) for space heating. Is the basement heated with copper tube /Alum fin baseboard? Is there a separate thermostat for that zone? If Yes, then there should be another zine valve for the original radiators somewhere. I only see one zone valve. Where is the other?

    By the piping near the boiler, I can tell there is an overheating possibility when the oil heater is maintaining temperature for DHW. This would not be a problem if you decide that electric heating is your best option. Just leave the oil heat OFF. then it can not overheat.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • shanzzie
    shanzzie Member Posts: 13
    @EdTheHeaterMan we have 3 thermostats. One in the basement and two upstairs living room & master bed.
    I believe these are the other two you are looking for?
    And yes, copper pipe with the aluminum fins. Took a pic of the one under the kitchen sink, as it's the only one without a cover.




  • SuperTech
    SuperTech Member Posts: 1,585
    I have never seen anyone preheat the incoming water to the boiler like that, I agree that is a clever idea!
    EdTheHeaterMan
  • shanzzie
    shanzzie Member Posts: 13
    @SuperTech Quebecers never cease to amaze me with some of the things they come up with. I've seen some pretty interesting things over the years. :)
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 1,836
    @shanzzie
    Happy to help. It looks like you have a great system, well thought out by the installer. I wonder if you can locate the company that did the service. They will be a valuable asset if there is a service call. The control wiring can confound some technicians. Zone valves and the dual boiler selection needs a technician just a step above the regular maintenance/parts-changer mechanic.

    Also, you want to keep some fuel in the tank. Near full if possible because you never know when you might need it, and the air space in the tank is a great place for condensation to form. Make a habit of operating the oil burner for a day or so each cold month. Keep the parts moving so they don't get stuck from sitting idol.

    Good luck with your system.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
    shanzzie
  • shanzzie
    shanzzie Member Posts: 13
    @EdTheHeaterMan not sure who did the install, previous owner didn't say anything. I did call someone to come take a look, he checked the system at no cost .. everything is great, works, etc.
    He also advised to keep some oil just in case it gets real cold.
    Currently the price of heating oil here is 0.699/litre and we have a 900L tank. Coldest moths are Dec, Jan & Feb.
    Again, appreciate all the help you provided. :)<3
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