Domestic Hot Water - Rheem Raypak MVB 503A Installation And Operation Manual

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Installation and operation manual (40 pages)

Table Of Contents

Table of Contents

Mode 2 (Type H Units Only)

This mode selection is for hydronic heating systems with

single or multiple boilers in primary/secondary piping

configuration with or without Outdoor Air Reset (S4) with

indirect DHW on the system loop (with or without priority).

The system temperature is controlled by the System

sensor (S3). The Indirect DHW sensor (S5) determines

the indirect call/tank setpoint. The system temperature

is boosted to Target Max when using the Indirect DHW

sensor (S5) during an indirect call for heat. Priority mode

toggles off the System Pump (P2) when an indirect call

for heat is present. The Boiler Pump (P1) runs during any

call for heat. The Indirect DHW Pump (P3) runs during an

indirect call for heat with no "off" delay. The Boiler Pump

(P1) and System Pump (P2) delay "off" as user defined in

the ADJUST menu. The System Pump (P2) runs whenever

the system is enabled for heating and the outdoor air

temperature is lower than the WWSD temperature setting

(if utilized) unless an indirect call for heat is present with

priority. See Figure 14 .

MODBUS

VERSA

ENABLE

0–10 / 4–20mA

PIM

FACTORY INSTALLED SENSOR

FIELD INSTALLED SENSOR

Maximum distance 4 system pipe diameters,

not to exceed 12" (305 mm)

Figure 14. MODE 2 - Single Boiler with Indirect in System

Loop

Mode 3 (Type H Units Only)

This mode selection is for hydronic heating systems with

single or multiple boilers in primary/secondary piping

configuration with or without Outdoor Air Reset (S4)

with indirect DHW on the boiler loop (with priority). The

system temperature is controlled by the Supply sensor

(S3) whenever the indirect call for heat is not active. The

DHW Supply sensor (S5) determines the indirect call/tank

setpoint. During an indirect call for heat the boiler firing

rate is determined by the water temperature at the Indirect

AQUASTAT

LOCATED IN

OUTLET PIPE

F10710

Supply sensor (S6) and the Target Max setting when using

the Indirect DHW sensor (S5). The Boiler Pump (P1) runs

during all heat calls regardless of priority. The Indirect

DHW Pump (P3) runs during an indirect call for heat with

no "off" delay. The Boiler Pump (P1) and System Pump

(P2) delay "off" as user defined in the ADJUST menu. The

system pump (P2) runs whenever the system is enabled

for heating and the outdoor air temperature is lower than

the WWSD temperature setting (if utilized) unless an

indirect call for heat is present. See Figure 15.

NOTE: A Tank Aquastat can be used in lieu of the

Indirect DHW Sensor (S5). See the VERSA IC ® manual

(241493) for additional details.

NOTE: In cascade configuration, the system pump and

DHW pump (if applicable) outputs from each cascade

member and must be connected in parallel to active

the system pump and DHW pump during "limp-along"

operation respectively. See the VERSA IC ® Manual