Brochure

117
Selection Guides
Hoffman Specialty
®
Selection Guidelines
Type of Heater Application Type of Regulator
Domestic Hot Water Series 2000 with pneumatic pilot for ± 4˚F (± 2.2 ˚C).
(must be used with anti-scald protection)
Process fluids Series 2000 with pneumatic pilot for ± 4˚F (± 2.2 ˚C).
Series 2000 with STPA pilot for ±10˚F (± 5.6 ˚C).
Instantaneous Heater (System recirculation is recommended)
Wash down stations Same as process fluids (Pneumatic recommended
if available)
Steam to water converters Series 2000 with either direct or pneumatic
operated pilots. ± 10˚F (± 5.6 ˚C) accuracy.
Semi-instantaneous Heater Domestic hot water Series 2000 with pneumatic temperature pilot ± 4˚F
or
(± 2.2 ˚C) accuracy (must be used with anti-scald protection)
Storage Heater Process fluids Series 2000 with pneumatic temperature pilot ± 4˚F
(± 2.2 ˚C) accuracy. Direct-operated pilots ± 10˚F
(± 5.6 ˚C) accuracy.
Wash down stations Same as process fluids
Typical Guidelines for Selection of Temperature Regulators
The degree of temperature variation depends on load
change. The chart below is based on 0% through 100%
load change.
3. When the outlet steam pressure is 50% or less of the
inlet pressure, use the lowest outlet pressure shown in
the capacity table.
Answer:
1. Using the above data and referring to the Normal Port
Capacity Table page 46, a 1
1
⁄4" NPT main valve with a
normal port that passes 2880 lbs./hr. (1306 kg/hr.) of
steam would be selected.
The order would be for:
One, Model 2100, 1
1
⁄4" NPT Main Valve-Normal Port.
2. Since temperature must be controlled, a combination
of spring and temperature pilots should be selected.
This would be:
One Model SPS-60 with adjustable range of 5 to 60
psi. (0.3 to 4.1 bar) or one Model SPS-30 with
adjustable range of 2 to 30 psi (0.1 to 2.0 bar). The
pilot would be adjusted to the required 20 psi (1.4 bar).
One Model STPA-200 with a temperature range of 50-
200°F (10-93°C) would be selected and adjusted to
150°F (65°C) to maintain the desired temperature of
water leaving the heat exchanger.
NOTE: An alternate option is to use a pneumatic
temperature pilot with an air pressure pilot and an
air regulator. This would be:
One Model 315 PNT with a temperature range
of 50-300°F (10-149°C) adjusted to 150°F (65°C)
to maintain the desired temperature of water
leaving the heat exchanger.
One Model AP-1A Air Pressure pilot to receive
the control signal from the pneumatic
temperature pilot.
One Air PRV Regulator, adjusted to maintain a
maximum 20 psi (1.4 bar) outlet pressure.
Example 2. (continued)
Sizing Examples
Series 2000
Pressure and/or Temperature Pilot Operated Steam Regulators (continued)