Image DE 30 Instruction Manual page 34

INSTALLATION PROCEDURES
2. High – Pressure Steam (16 – 125 psig) Motorized Steam Valve Models
Adherence to the following instructions is necessary to eliminate coil failures due to water
hammer caused by wet steam.
This is a slow opening and closing valve which will significantly reduce water hammer.
Remove the motor cover and connect the power wires to the motor's terminal strip per the wiring
diagram supplied with the dryer. The motor operates at 120 volts only, so a power transformer will
be supplied with the dryer if input voltage to the dryer is higher than 120 volts. It is important to
remember that the motor requires electrical power to open and close the valve. If the main dryer
power is cut off when the steam valve is open it will remain open. Steam flow must be in the
direction of the arrow printed on the steam valve body.
The presence of condensate in the steam supply will cause water hammer and subsequent
heat exchanger failure. The steam supply connection into the main supply line must be made with a
minimum 10" riser. This will prevent any condensate from draining towards the dryer.
The steam supply piping to the dryer must include a 12" rise along with a drip trap and
check valve. This will prevent any condensate from entering the steam coil.
Flexible hoses or couplings must be used. The dryer vibrates slightly when it runs, and this
will cause the steam coil connections to crack if they are hard piped to the supply and return mains.
Shut – off valves for each dryer should be installed in the supply, return, and drip trap return lines.
This will allow the dryer to be isolated from the supply and return mains if the dryer needs
maintenance work.
Install an inverted bucket steam trap and check valve at least 12" below steam coil as near to
the coil as possible.
A vacuum breaker should be installed in the piping. This will prevent the condensing steam
from causing a vacuum inside the coil and possibly damaging the coil.
The supply and return lines should be insulated. This will save energy and provide for the
safety of the operator and maintenance personnel.
Water pockets in the supply line, caused by low points, will provide wet steam to the coil
possibly causing coil damage. All horizontal runs of steam supply piping should be pitched 1/4"
every foot back towards the steam supply header causing any condensate in the line to drain to the
header. Install a bypass trap in any low point to eliminate wet steam.
We recommend an inverted bucket trap for high pressure dryers. DO NOT use
thermodynamic disc or impulse traps.
The condensate return line may be elevated after a bucket trap, but only if there is sufficient
line pressure to overcome the head. Determine head, loss by deducting 12 Psi for the control valve,
coil, and trap losses, and, deduct 1/2 Psi for each foot of elevation.
3-21