TACO outdoor reset when using a priority DHW zone


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Old 10-20-14, 08:21 AM
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TACO outdoor reset when using a priority DHW zone

I have a ZVC404-EXP zone control set up with a priority zone for DHW (zone valve, not circulator). I also have a PC700 outside reset. It seemed to get stuck in hot water mode because the PC700 set the boiler too close to the DHW setpoint. I am guessing I should switch to a PC702 that will set the boiler to 180 when in priority mode. Is this correct or is there another option? What do I do with the stage 1 and stage 2 outputs of the PC702? Can the DHW demand wires just be paralleled with the zone valve motor for the priority zone?
 
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Old 10-20-14, 01:05 PM
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Hello and welcome to the forums..

For reference...PC 700

http://s3.supplyhouse.com/manuals/13..._PROD_FILE.pdf

Can you tell us the make and model of the boiler please? Also make and model indirect?

Once we get that info we can work on getting an answer to your issue.
 
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Old 10-20-14, 04:04 PM
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I don't think you want the 702, that one is for MULTI-STAGE boilers which you don't have.
 
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Old 10-20-14, 04:16 PM
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It seemed to get stuck in hot water mode because the PC700 set the boiler too close to the DHW setpoint.
I'm not sure what you mean by this?

You mean that the boiler is operating at the ODR setpoint even on a call from the DHW and doesn't get hot enough to bring the DHW tank up to temperature?

It shouldn't do that. It should fire to high limit on a call from DHW.

Do you have the dipswitch "RESET - NORMAL" pushed over to RESET?
 
 

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