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How to add a second zone?

Sharkbite
Sharkbite Member Posts: 7
in Thermostats and Controls
Hi, Need help please, I’m trying to wire in a second zone using circulating pumps .
I have a Utica model MGB-100J forced hot water boiler.
There’s a “Honeywell Integrated high limit electronic ignition control #240008781” on the boiler with one zone wired in working great.
I believe I need to wire in a switching relay to control another zone.
I'm thinking a Taco SR501 or a SR503, but don’t know how to wire it to the current Honeywell control on the boiler?
Link to installation manual of my boiler here:
http://www.ecrinternational.com/secure/upload/document/3625.pdf
Link to sr501 instruction sheet here:
http://www.taco-hvac.com/uploads/FileLibrary/102-375.pdf
Link to sr503 instruction sheet here:
https://www.taco-hvac.com/uploads/FileLibrary/102-167.pdf
Thank you for looking and hopefully somebody can help me.

Comments

  • ProblemSolver
    ProblemSolver Member Posts: 190
    You also need to show a picture of how the boiler is piped with all the controls, outside of the boiler, that are in your system. Need to know: is the boiler piped for 2 zones - 2 supply runs & 2 returns? do you have zone valves now and you want to convert to pumps? No one should help you on this unless you give more information with pictures; too many things could happen when there are unknowns.
  • Sharkbite
    Sharkbite Member Posts: 7
    Sorry, I could get pictures later if need be, but in the mean time I can tell you.
    The boiler is already piped for two zones, yes two supply runs and two returns.
    I have NO zone valves. I have just two taco pumps. One pump is already wired into the Honeywell control.
    All the plumbing part is complete, just need to know how to wire in the second zone.
    I think I need a TacoSR503 but don’t know how to wire in in.
    Thank You
  • Robert O'Connor_12
    Robert O'Connor_12 Member Posts: 728
    If one pump is already wired in, why not go for the 501? Pretty simple really. The 2 wires from new zone room thermostat goes to the R W (TT) terminal on the 501. The Two end terminals on bottom right (#6 and #5) go to the TT on the boiler. Bring 110v supply to the N H terminal. Lastly, Run wire from N & 4 to circulator.
  • Sharkbite
    Sharkbite Member Posts: 7
    Ya but right now I have 1st floor thermostat connected to tt wires on boiler so when it calls for heat it turns on pump and boiler. Now if the 2nd floor thermostat going to the 501 calls for heat yes it would turn on the pump and boiler for the 2nd floor but wouldn't it also turn on the 1st floor pump to, because the tt wires from the 501 are going to the same tt wires as the 1st floor.
    Hope I explained that OK
  • ProblemSolver
    ProblemSolver Member Posts: 190
    You explained perfectly. You have to use the 503 control and remove the 1st floor pump from the honeywell control and add it to the 503.
  • Sharkbite
    Sharkbite Member Posts: 7
    And I believe the 1st floor thermostat wire from the honeywell and put it on the 503, it's making sense now.
    It's cheaper and don't think I would go this route but would using 2 501's work. 1st floor pump + TT to 501 and 2nd floor pump +TT to the other 501 with both 6+5 terminals on 501's going to TT on the honeywell?
  • ProblemSolver
    ProblemSolver Member Posts: 190
    also, add the 1st floor T-stat to the 503. Using the "cold start boiler application" Let the X1 -X2 connection on the 503 bring the boiler on (with nothing connected to the honeywell control pump terminals). Using this application, the X1 - X2 terminals will use power from the boiler to operate the boiler; and the pumps along with the thermostats will use the 503's power. This assures that you are not crossing two different power sources with each other. Very important: set the jumpers on the 503 exactly as they show for the "cold start boiler application". To power up the 503, you can tap off the power switch from the boiler (before the switch) and add a switch for the 503. Wiring it like this helps with service in some cases. P5-1 & P5-3 CHT-T on the boiler's circuit board is the call for heat. (CHT-T) = Central Heating Thermostat Connections.
  • ProblemSolver
    ProblemSolver Member Posts: 190
    The sequence of operation will work like this: the boiler will NOT operate to maintain a boiler water temperature. The boiler's burner will only come on when a thermostat is calling for heat. Therefore, it would be a good idea to insulate all the near boiler piping (supply and returns) with (1" wall thickness) fiberglass insulation for pipe. Do not use the foam insulation because it does not handle the high temperatures very well. Doing this will help maintain the hot water in the boiler during long off times between calls for heat; and save you some $$$ on your gas bill.
  • ProblemSolver
    ProblemSolver Member Posts: 190
    The type of fiberglass insulation I am talking about is what is used for insulating "Steam Boiler Pipes". My local supplier belongs to a national group called "Service Pros". Look them up to see if there is a supplier near you.
  • ProblemSolver
    ProblemSolver Member Posts: 190
    Oh, in case you are wondering; the "24 vac power" in the upper left corner of the 503 control is a 24 volt tap off the 503's transformer. 99% of the time it is never used, but it's there for some pretty tricky control wiring that does not apply to you; so don't pay attention to it.
  • ProblemSolver
    ProblemSolver Member Posts: 190
    Using the "typical wiring" application, sure go ahead, if it is cheaper
  • ProblemSolver
    ProblemSolver Member Posts: 190
    Because the 5 & 6 terminals on the 501 are isolated from the 501's power - both of the 501's will be using the boilers power (transformer) to bring on the burner and there will be no back feeding of a call for heat from one 501 to the other; so 2 of them will work just fine. How much cheaper?
  • Sharkbite
    Sharkbite Member Posts: 7
    With tax and all only $23.20 plus with the 503 I get extra zone if needed later.
    By the way this is the 503 I will purchase, instruction sheet is a little different but starting to make sense. Please take a look.
    http://s3.supplyhouse.com/manuals/1351150925280/85270_PROD_FILE.pdf
    Am I right in saying I will Remove the existing pump from the boiler control along with the thermostat wiring.
    Install the 503 and wire the existing thermostat and pump to one of the 'channels' in the 503.
    Connect the new thermostat and pump to another of the 503 channels.
    Connect the ENDSWITCH from the 503 to the thermostat input of the boiler.
    The circulator output of the boiler control will not be used.
  • ProblemSolver
    ProblemSolver Member Posts: 190
    Bingo !!!! You got it.
  • Sharkbite
    Sharkbite Member Posts: 7
    Thank you!!
    I felt so close to figuring this out, and how simple it seems now.
    I will post my results when I get around to finishing the job in a few day’s.
    Thank you again all.
  • ProblemSolver
    ProblemSolver Member Posts: 190
    Don't forget pictures of the boiler and all the near boiler piping. Pictures tell us a lot of things on what is and is not correct; doing it with words takes too long. We are always interested in where the components around the boiler were placed.
  • Sharkbite
    Sharkbite Member Posts: 7
    I appreciate that and will post so pics, might take a few days.

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