Control Unit Model

Ventilation by Gas Fired Air Handling Units

Northern Industrial Company offers various models of Make-Up Air Units for larger industrial plants ventilation requirements.

Negative Air Pressure in industrial manufacturing facilities can create problems such as:

* Exhaust fans losing performance, as the building pressure becomes negative.

* Pilot light outages and exhaust system failure on natural draft gas equipment.

* Cold air drafts and infiltration of dirt and contamination from outside.

* Difficulty opening or closing exterior doors.

Northern Industrial air-handling units (AHU) can be used effectively for negative pressure control at manufacturing facilities:

Space Pressure Control is used to minimize and control the exchange of air between the building and the outside environment or from one building area to another. This may be accomplished in three ways:

- Constant air supply with variable-speed exhaust;

- Variable air supply with constant-speed exhaust;

- Variable Return-Air.

Constant air supply with variable-speed exhaust is recommended where a hot or contaminated environment must be ventilated while maintaining room pressure. Unit may be interlocked to that it only operates with the exhaust system.

Variable Air Supply with constant-speed exhaust may be preferred where fume exhausters or fume hoods are used to provide critical ventilation of contaminants from a “clean” environment while make-up air is used to maintain a positive pressure to prevent infiltration.

In either case, when the system is enabled, a pressure sensor in the building space monitors room pressure. When a high or low pressure reading is detected, the air supply or exhaust is adjusted to compensate.

When controlling a Variable Air Supply unit (or VAV Unit - Variable Air Volume), two methods are available:

- Damper Control - Unit discharge damper is adjusted using the damper motor.

- VFD (Variable Frequency Drive) – Controller adjusts the speed of the blower motor Discharge Damper adjustment is an older method of controlling discharge air volume. Its main advantage is that it only requires positional control of a small discharge damper motor. The major disadvantage is the wasted Horsepower of the blower motor at lower delivery rates.

In recent years, fan speed control using VFDs has become economical. In this application, a standard energy efficient motor is usually adequate down to 75% of normal motor speeds. For a fan speed down to 25%, a premium efficiency motor is required. Inverter duty motors are not usually necessary since at 25% of normal fan speed, air delivery is minimal.

Variable Frequency Drives are also programmable. They are used to provide soft starts and to ramp motor speed up or down in response to signals from the control system.

Finally, in a generally “clean” environment without a critical need to remove large quantities of contaminants, a simple solution to building pressurization is a Return Air Unit with the return air damper motor controlled by building a pressure sensor. When building pressure increases, more inside air is returned through the unit, relieving the pressure. When building pressure falls, more outside air is supplied to the building in order to “pump up the pressure”. Precise control of building pressure by a single piece of equipment can thus be achieved.

Additional information can be found at the Northern Industrial company web site http://northernindustrialsupplycompany.com/products/air_handling_units.html.

Oleg Cthetchel
Industrial Ventilation Systems Designer
Northern Industrial Co.
http://northernindustrialsupplycompany.com/index.html
http://northernindustrialsupplycompany.com/products/index.html

About the Author

Oleg Cthetchel
Industrial Ventilation Systems Designer
Northern Industrial Co.

http://northernindustrialsupplycompany.com/index.html

http://northernindustrialsupplycompany.com/products/index.html

Stiebel Eltron Tempra 12 Plus – Ideal For Sinks.

For small households, multi kitchen or bathroom appliances, the Stiebel Eltron Tempra 12 Plus Tankless Water Heater is a common point-of use tankless water heater. Stiebel Eletron Tempra 12 Plus constantly heats water instantly as you require it and only when you require it.

In order to reduce the usual temperature variation you have the Advanced Flow Control technology which adjust the flow of the water regurarly. This equates to you in a consistently enjoyable experience every time, all the time.

The Stiebel Eltron Tempra 12 Plus comes with a covenient temperature display and temperature control which can be set at any level between 86°-140°F (30°-60°C). The Stiebel Eltron Tempra 24 Plus will automatically sense the water flow rate and temperature, calculate how much power is needed to do the job, and will apply exactly that much power so it can precisely maintain the desired output temperature regardless of whether the flow rate changes or not. It has to most accurate temperature control ability that any heater in the market today.

The water temperature can be adjusted and the unit will not produce water over 140°F with built in ‘Safety Guard’.

The Stiebel Eltron Tempra 12 reduces hot water costs up to 60% over conventional electric water heaters. Anyone can install this compact heater without worrying about pressure valves.   Due to its energy efficiency expect to save lots of money. Without additional costs, the Stiebel Eltron Tempra 24 tankless electric water heater can give you heated water anytime you want.

Other great feature of the Stiebel Eltron Tempra 12 electric tankless water heater are its small size compared to other water heaters and this will save you more living space.

Welcome to the next generation of German quality.

The Stiebel Tempra 12 electric tankless water heater comes with a 3 year warranty on all parts and the company's German engineering and manufacturing tradition of excellence means that you can depend on its performance for many years to come.

 

 

 

hunter Sprinkler Sys. Control Box Model PC-300 (3 program, 6 zone)problem?

When setting watering days, the water icon does not appear. When selecting the "no watering " days, the no water icon works ok. Water icon does not work on any of the 3 programs in the box. Any way to repair this without replacing the entire unit?

I really don't know what you are talking about.

New Jammer Power System Passes Technology Readiness Tests (SpaceWar)

El Segundo, CA (SPX) Dec 14, 2011

A critical power generation subsystem of Raytheon's Next Generation Jammer has
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