Relays for roomstat question

Discussion in 'Boiler Forum' started by Toledo, Nov 25, 2009.

  1. Toledo

    Toledo New Member

    Messages:
    3
    Location:
    Toledo Iowa
    I have a question related to relays and how to configure them to activate my boiler and or my pump - I wonder if you can help me out?


    I have a room stat with a connector block labeled left to right Rc Rh (jumpered together) B O Y W G C

    I have a 24v transformer which is connected to Rh (hot wire) and C(ommon) - C is jumpered to W and Y All I need is for the system to run either the boiler and pump hot water or just the pump on its own to pump cold water around the system.


    I have a Totaline relay P283-0370 and a White-Rodgers 90-293Q relay (the supplier didn’t have 2 of the same relays available).

    From the 90-293Q relay I have terminal 1 connected to the 'Y' port at the room stat and the 'W' port connected to terminal 1 on the P283-0370 relay . The pump is connected to #2 terminal on both relays. The boiler to terminal 5 on the 90-293Q relay. A 120V supply to #4 terminals on both relays and also the 120v/24V transformer. The #3 terminals are 24V supplies and connected together and on to the common side of the transformer which is connected to the C(ommon) terminal on the room stat - The live 24v terminal (hot) is connected to the Rh terminal at the room stat. However when it is wired this way all I get is the pump only running constantly and no control is evident from the room stat.

    If the pump and the boiler are wired together I simply cant run the pump without the boiler lighting without physically disconnecting the boiler.

    The situation is that if the pump operates then the boiler ignites so I have to isolate the power from the boiler when I want it to run cold so it can’t ignite.

    I need to either have heat on which is pump and boiler or cold which is pump only. Do you have any suggestions as to how I can make this work?

    The Word doc I have all of the digrams in is 127Kb and too big to post here but I can mail it, if required, direct I guess
  2. MAoilTech

    MAoilTech New Member

    Messages:
    25
    Location:
    MA
    What brand model is your boiler?
    Also send me what info you have.
    Last edited: Nov 26, 2009
  3. Toledo

    Toledo New Member

    Messages:
    3
    Location:
    Toledo Iowa
    Boiler details

    Hello
    The boiler is a Hydro-Smart 170; the installation manual is too big to upload
    The room stat is a Braeburn 2000 Series Room Stat the relays are shown on the previous post and the pump is a Tico circulating pump. The transformer is 120v - 24v transformer
  4. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    Just out of curiosity but why do you want to run the pump without firing the boiler and how are you trying to have this achieved?
  5. Toledo

    Toledo New Member

    Messages:
    3
    Location:
    Toledo Iowa
    The system works on thermal mass and conductive cores. The building has an R50 envelope and requires only small amounts of heat or cool to maintain the 'internal climate'. In Summer at 100oF outside it gains 5-9oF in winter at 25oF it looses less than 5oF.

    I design buildings and this particular design is a Scandinavian adaption. However the controls in the US are not the same as in Europe and it is beyond local knowledge as they have never seen controls that are not 'snap together' as many are.

    If run in tandem the flow created by the pump automatically starts the boiler. The in built controls in the boiler are of no use for this application. I simply need the room stat to either switch on power to both the pump and the boiler so as the pump starts the boiler which will automatically ignite but in the heat of summer just the pump will run pumping cool street main temperature round the system cooling the cores and hence lowering the temperature of the thermal mass claiming the small increases in temperature from the space. The room stat has a hot and a cool setting (as well as others) but these are the only two I require.

    I have already bypassed the stat and confirmed it will work but the stat will make this automatic as opposed to a manual operation.

    This is something quite rare in the US moreso in Iowa so it is very difficult to try to make them understand the concept.
  6. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    I think the easiest thing to do would be to run a Heat/Cool thermostat and have the heat side trip a relay that will fire up the boiler and run the pump and have the cooling side trip a relay that will fire up only the pump.

    Your boiler should not run just because the pump is on (unless the boiler controls the pump and the brains of the boiler tell it to fire. Does it? If so you need to wire the pump up separately from the boiler.

    I have never seen or heard of the control you have but if it's anything like a regular heat/cool thermo-stat then my method should still work.
    Last edited: Nov 26, 2009
  7. WISCAN

    WISCAN New Member

    Messages:
    1
    Location:
    Racine, WI
    Hydro-Smart 170 Boiler

    I saw this boiler at ******* and I wonder if anybody has any comments about it as it appears to be a quality unit at a great price. Regarding the controls, as I understand it, the boiler has an internal flow switch that starts the boiler when the flow is sufficient (pump on). I think it would need a dedicated starter relay for the boiler that only allows the boiler to power up when heating is selected.
  8. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    The boiler shouldn't fire just because there is flow if there isn't a call for heat across the T T terminals. Flow switches are proving switches that's it.

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