Electrical Power Connections - Raypak 503A Installation & Operating Instructions Manual

1 in. NPT
Model
No.
N
503A 15
753A 5
1103A
1253A
1503A
1753A
2003A
• Natural Gas – 1,000 BTU/ft
• Propane Gas – 2,500 BTU/ft
Model
Natural Gas
503A
753A
1003A
1253A
1503A
1753A
2003A
NOTE: Manifold pressures should be ±0.2 in. WC.
Table I: Manifold Gas Pressure Settings
CAUTION: For proper operation, no more than a
30% drop in gas supply pressure from no-load to full-
load conditions is
circumstances should the pressure be outside the
listed operational range.

Electrical Power Connections

Installations must follow these codes:
• National Electrical Code and any other national,
state, provincial or local codes or regulations hav-
ing jurisdiction.
• Safety wiring must be NEC Class 1.
• Heater must be electrically grounded as required
by the NEC.
• In Canada, CSA C22. 1 C.E.C. Part 1.
1-1/4 in. NPT
P N P
35 65 150
15 65 100
35 55
15 25
10 15
3
, 0.60 specific gravity at 0.5 in. WC pressure drop
3 , 1.53 specific gravity at 0.6 in. WC pressure drop
Table H: Maximum Equivalent Pipe Length
Manifold Gas Pressure
(High Fire Values)
Propane Gas
-4.7 -5.3
-4.6 -5.8
-5.9 -7.5
-6.3 -8.3
-8.3 -10.8
-4.5 -7.6
-6.4 -10.4
acceptable. Under
1-1/2 in. NPT
N P
130 360
75 180
35 90
25 60
15 25
The MVB 503A-1503A heaters are wired for 120 VAC,
12 amps while the MVB 1753A & 2003A heaters are
wired for 120 VAC, 18 amps. Consult the wiring dia-
gram shipped with the heater. Before starting the
heater, check to ensure proper voltage to the heater
and pump.
Pumps must use a separate power supply and run the
power through the pump contactor, which is located in
the rear wiring box. Use appropriately-sized wire as
defined by NEC, CSA and/or local codes. All primary
wiring should be 125% of minimum rating.
If any of the original wire as supplied with the heater
must be replaced, it must be replaced with 105°C wire
or its equivalent.
All high voltage wiring connections to the MVB heater
are made inside the rear wiring box as shown in
Fig. 18. Power for indirect DHW pump not exceeding
5 amps should be taken from terminals 4(Hot), 5
(Com), and 6 (Gnd). Power for system pump not
no
exceeding 5 amps should be taken from terminals 7
(Hot), 8 (Com), and 9 (Gnd). Power for boiler pumps
3/4 HP and smaller should be taken from terminals 1
(Hot), 2 (Com), and 3 (Gnd), and must be routed
through the pump contactor; 30A supply is required.
Power for pumps larger than 3/4 HP must be a sepa-
rate circuit wired through the pump contactor. Power to
the MVB heater should be connected to Terminals 1,
2, and 3 as noted in Fig. 18. All low voltage wiring,
including sensors, interlocks, enable/disable, and var-
ious options are wired into terminals 1–24 on the front
wiring panel as noted in Fig. 23.
20
2 in. NPT 2-1/2 in. NPT
N P N
250
125 300 300
85 225 200
60 150 150
45 110 115
35 90 85
P
300
275
230
210