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I am a plumbing tech installing a Navien NCB-240E Combi for…

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I am a plumbing...

I am a plumbing tech installing a Navien NCB-240E Combi for domestic hot water and two furnaces (two pumps) what is the best relay to use for this set up and how do I wire up this system to work properly, replaced a voyager high efficiency water heater.

Contractor's Assistant: Did you check the furnace's filters?

Yes furnaces are new hot water circulation type, I just need information on wiring the two thermostats to the two pumps and the Navien

Contractor's Assistant: Do you plan on doing the work yourself?

Work is all complete except the proper wiring

Contractor's Assistant: Anything else we should know to help you best?

Norther California area so moderate climate never snow fall, What is best Taco controller (relay)

Submitted: 10 months ago.Category: HVAC
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Answered in 6 minutes by:
10/5/2017
HVAC Technician: Rick, HVAC Supervisor replied 10 months ago
Rick
Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 24,602
Experience: 40+ yrs. experience as a licensed oil & gas technician.
Verified

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

A Taco SR502 (2 zone relay) or 2 SR501's are suitable. If Taco isn't available where you are Argo makes similar relays. You wire the zone thermostat to the T terminals on the relay (R & W) , connect the pump to the pump terminals for the corresponding zone then connect relay end switch to TT on the Navien. Here's a link to SR502 wiring diagram.
https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1351149688246/85262_PROD_FILE.pdf

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