CLOSING POWER ADJUSTMENT
Closing power is adjustable according to door weight and width by adjusting the spring power. To increase closing power, turn spring adjusting nut clockwise. To decrease closing power, turn spring adjusting nut counterclockwise. This closing power adjustment function is equipped with D-4550, D-3550 and D-2550 series door closers.
FULL HYDRAULIC CONTROL
Controls the door through the entire opening and closing cycles by providing adjustable backcheck upon opening and adjustable general and latch speed through the closing cycle. A separate hydraulic valve allows adjustment to delay the closing speed from 180 to 70 degrees of door opening range.
*This illustration shows the position of each valve for D-3550DA.
A backcheck feature set and adjusted by an independent valve.
When introduced the backcheck stalls the opening of the door around 70 degrees.
When doors are violently opened by pedestrians or wind, the backcheck feature
reduces the likelihood of damage should contact be made with an adjacent wall
or obstacle. For busy doors in public building, schools and colleges this facility
protects people and property.
OPTIONAL DELAYED ACTION
An optional delayed action feature adjusted by means of an independent
valve. Once set , the door - when opened beyond 70 degrees enters into a delayed
mode allowing additional time before the closing. Delayed time can be adjusted
to vary from seconds to minutes depending on the angle to which the door is opened.
Delayed Closing Action is an advantage to : Nursing staff assisting patients,
Domestic staff pushing meals or maintenance trolleys, and the elderly or infirm
walking with sticks or frames under supervision.