EWC Controls ULTRA-ZONE NCM-3z Technical Bulletin page 14

System Wiring
The NCM-3z Zone Control is Hydronic (Hot Water) heat friendly, due to the Rc/Rh "system" isolation circuit and there's no need to install
an Aqua-Stat. But wiring these systems can be challenging because you are introducing a foreign 24v source (T&T from the Boiler) into
the Air Handler and into the Zone Controller. This foreign voltage must remain isolated from the 24v source in the Air Handler!
Older Air Handlers with Permanent Split Capacitor (PSC) motors provide the proper CFM when only the "G" fan circuit is energized.
These older inefficient Air Handlers don't need to detect the "W" heating signal, so you can use the NCM-3z Rc/Rh isolation feature.
* Figure 15 is for old tech PSC motor types. Cut the Rc/Rh link (to isolate) and connect the Boiler T&T circuit straight to the Rh and W1/B.
New Tech Air Handlers with Variable Speed motors
board detects the "W" heating signal. The "G" fan circuit runs at low speed only, so you cannot use the NCM-3z Rc/Rh isolation feature.
* Figure 16 is for new tech VSP/ECM motor types. The isolation relay is required
must detect the W signal from the Air Handler's 24v power, not the Boiler's 24v power.
* Figure 17 pertains to First Company® Air Handlers only. This OEM provides the isolation circuit for you. There's no need for a field relay.
* Figure 18 is for Heat Pump applications where the Hydronic coil is the auxiliary heat source. The isolation relay is required
because the reversing valve must detect the O/B signal from the Air Handler's 24v power, not the Boiler's 24v power.
the Rc/Rh isolation)
* If you're unsure of the motor type in your Air Handler, use an isolation relay!
OUTDOOR
CONDENSING
UNIT
Y
C
To the Boiler Control
T & T terminals.
The relay's dry contacts
will close this circuit
when the W1/B output energizes
T
T
Figure 15
FIRST COMPANY®
OUTDOOR
CONDENSING
UNIT
Y
C
OEM provided
ISOLATION
(dry contact)
TERMINALS
OR WIRES
To the Boiler Control
T & T terminals.
The Air Handler's dry
contacts will close this circuit
when the W1/B output energizes
Figure 17
14
EWC Controls Inc. 385 Highway 33 Englishtown, NJ 07726 800-446-3110 FAX 732-635-8646
Two Transformer Hydronic Heating Systems
PSC MOTOR
Air Handler
NCM-3z
Terminal
Block
"W" terminal
may not exist!
W
W
Y Y
G
G
R
R
C
C
RC - RH RC - RH
S1 - S2 S1 - S2
Set FAN mode to HYDRO!
Set FAN DELAY to 45 seconds
Air Handler
NCM-3z
Terminal
Block
W
W
Y Y
G
G
R
R
C
C
T T
RC - RH RC - RH
S1 - S2 S1 - S2
DO NOT cut
the Rc/Rh link
T
Set FAN mode to HYDRO!
T
Set FAN DELAY to 45 seconds
will not provide the proper heating CFM, unless the VSP circuit
(ECM High Efficiency)
OUTDOOR
CONDENSING
UNIT
SYSTEM SYSTEM
W2/E
Y
W1/B
O
Y C
G
RH
RC
C
LINKS LINKS
CUT the
Rc/Rh link!
To the Boiler Control
T & T terminals.
The relay's dry contacts
will close this circuit
when the W1/B output energizes
Figure 16
Heat Pump
"O" type
W/X
SYSTEM SYSTEM
Y
W2/E
W1/B
R
O
Y
C
G
RH O
RC
C
LINKS LINKS
To the Boiler Control
T & T terminals.
The relay's dry contacts
will close this circuit
when the W2/E output energizes
Figure 18
(cannot use the Rc/Rh isolation)
depending on HC or HP application.
(Figure 16 or 18)
ECM/VSP MOTOR
Air Handler
Terminal
Block
W
W
Y Y
G
G
R
R
C
C
SPST 24vac
Isolation Relay
(field supplied)
T
T
ECM/VSP MOTOR
Air Handler
Terminal
Block
W
W
Y Y
G
G
R
R
C C
SPST 24vac
Isolation Relay
(field supplied)
T
T
E-Mail- info@ewccontrols.com
because the VSP motor
(cannot use
NCM-3z
SYSTEM SYSTEM
W2/E
W1/B
O
Y
G
RH
RC
C
RC - RH RC - RH
LINKS LINKS
S1 - S2 S1 - S2
DO NOT cut
the Rc/Rh link
Set FAN mode to HYDRO!
Set FAN DELAY to 45 seconds
NCM-3z
SYSTEM SYSTEM
W2/E
W1/B
O
Y
G
RH
RC
C
RC - RH RC - RH
LINKS LINKS
S1 - S2 S1 - S2
DO NOT cut
the Rc/Rh link
Set FAN mode to HYDRO!
No need for FAN DELAY