Trane R Series Installation Operation & Maintenance page 64

Installation - Electrical
Also, provide a set of auxiliary contacts for condenser water pump starter
5K27 to interlock cooling tower fan starter (5K28) operation (if used) with the
condenser water pump starter. This insures that the cooling tower fan runs
only when the condenser water pump is operating.
Figure 27 Typical RTWA Chiller Interlock
Alarm/Running/Maximum Capacity Outputs
Terminals 1 to 7 on terminal strip TB4 of the 1U1 board provide a variety of
contact outputs on the RTWA and RTUA units. These are dependent upon
the setting of Programmable Relay Setup (Service Setting Menu) and its
relationship to diagnostics, compressors operating and the system operating
at full capacity.
As shown in Figure 19, there are three relays. Relays 1 has SPDT contacts.
Relays 2 and 3 have SPST normally-open contacts. The relays provide three
output configurations, as shown in Figure 19, and each configuration offers
four choices as to how each relay is to respond to a set of diagnostics.
Table 27 shows the twelve settings available in Programmable Relay Setup
(Service Setting Menu) and the diagnostics which are issued for each set of
conditions.
Alarm/Running/Maximum Capacity Indicator Wiring
If the optional remote Alarm/Running/Maximum Capacity contacts are used,
provide electrical power, 115 VAC (contact load not to exceed 1150 VA inrush,
115 VA sealed), with fused-disconnect to a customer furnished remote
device. Also provide proper remote device ground connection.
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