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LCBS
Applications Manual
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Honeywell LCBS Applications Manual

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LCBS Connect Solution
APPLICATION MANUAL
TABLE OF CONTENTS
Introduction .................................................................................................................................................................. 2
Background....................................................................................................................................................................................... 3
Automatic Building Schedules ................................................................................................................................ 4
Heating, Heat Pump Control .................................................................................................................................... 6
Droop, Comfort and Saving Heat Pump Mode ................................................................................................................... 7
Cooling, Dehumidification, Economizer Control ................................................................................................7
Cooling Operation .......................................................................................................................................................................... 8
Method #3: Dehumidification extended cooling minimum run time ....................................................................... 9
Fresh Air Economizer Control .................................................................................................................................. 9
Honeywell Integrated Economizer Control Described .................................................................................................... 10
Honeywell Integrated Economizer Control, Climate Zones .......................................................................................... 12
Honeywell Integrated Economizer Control - High Limit and Changeover Strategies........................................ 12
Strategy 1: Differential Enthalpy with Fixed Dry Bulb Temperature Limit .............................................................. 12
Strategy 2: Outdoor Air Enthalpy.............................................................................................................................................. 12
Strategy 3: Differential Temperature ...................................................................................................................................... 12
Strategy 4: Outdoor Temperature ............................................................................................................................................ 12
Low Limit Temperature Override Control ............................................................................................................................. 13
Freeze Stat Operation ................................................................................................................................................................... 13
Advanced Temperature Control Fundamentals..................................................................................................13
Proportional Control and the Concept of Differential and Throttling Range......................................................... 13
Proportional Control...................................................................................................................................................................... 13
Set point and Differential Refresher - On Off, Digital Control...................................................................................... 14
Integral Action Primer and Refresher Course for Some.................................................................................................. 15
Derivative Control........................................................................................................................................................................... 17
Demand Controlled Ventilation............................................................................................................................... 17
Theory and Operation Demand Controlled Ventilation .................................................................................................. 17
DCV Operation ................................................................................................................................................................................. 17
Adaptive Intelligent Recovery..................................................................................................................................18
LCBS CONNECT SOLUTION
Multispeed Fan ............................................................................................................................................................ 20
Multispeed Fan Theory and Operation................................................................................................................................... 20
Two speed motor .............................................................................................................................................................................20
VFD application................................................................................................................................................................................20
Direct drive "ECM" motor..............................................................................................................................................................20
Theory and Operation Accessory Loops ............................................................................................................... 23
How do Accessory Loops work?.................................................................................................................................................23
Service Alerting Theory and Fundamentals ........................................................................................................24
How does service alerting work?...............................................................................................................................................25
Terminal Load, Zone Demand Alert. ........................................................................................................................................ 25
Space Humidity Alert.....................................................................................................................................................................25
Space Zone Carbon Dioxide Level Alert .................................................................................................................................26
Differential Pressure Alerting, Filter Loading ......................................................................................................................26
Alerting Details................................................................................................................................................................................. 27
Appendix, Wiring Diagrams ...................................................................................................................................... 30
1. Master Points List - Configurable and Fixed Function Points.................................................................................30
2. Master Application Inventory - All Wiring Diagrams....................................................................................................30
3. Configurable Input and Output Assignments Wiring Diagram ...............................................................................31
4. Fixed Input and Output Assignments Wiring Diagram ...............................................................................................32
5. Two Heat Two Cool Integrated Economizer Single Temperature Changeover Limit ......................................33
6. Two Heat Two Cool Integrated Economizer Differential Enthalpy Changeover and
Temperature Limit.....................................................................................................................................................................34
7. Two Heat Two Cool Integrated Economizer Differential Enthalpy Changeover and Temperature
Limit and Demand Controlled Ventilation.......................................................................................................................35
8. Three Heat Three Cool Multispeed Fan with Variable Frequency Drive ...............................................................36
9. Single Stage Heat Pump with Economizer Differential Enthalpy Changeover and
Temperature Limit.....................................................................................................................................................................37
10. Two Stage Heat Pump with Economizer Differential Enthalpy Changeover and Temperature Limit ...38
11. Simple Dehumidification......................................................................................................................................................39
12. Two Speed Fan with Discrete Fan Outputs Two Heat and Two Cool ...................................................................40
13. Outdoor Ambient Lighting Control with Photosensor Input to Control Outdoor Light Level ..................41
14. Sylk Sensor Installation Relating to LCBS Connect Controller .............................................................................42
INTRODUCTION
The LCBS Connect Solution features controllers that support multiple CVAHU applications, including rooftop units, split systems and air to air heat pumps and a new Gateway that permits controller data to be sent from individual CHAHU controllers via the internet to the new LCBS Connect Cloud. The new Honeywell Cloud capability gives our control system users unprecedented access to data remotely via standard smart phones, tablets, and personal computers. Honeywell also performs data analysis, called “analytics,” that will permit service contractors and building owners to effectively and efficiently manage HVAC assets. Here are a few specific features of the new LCBS Connect solution.
— Occupancy Control. Daily and holiday schedules are available to ensure that building occupants, employees, and
visitors are comfortable when they are in the building and that owners achieve maximum energy savings when no one is occupying the building. Honeywell patented Adaptive Intelligent Recovery monitors outdoor and indoor cli­mate conditions to ensure comfortable conditions when building occupants arrive.
— Advanced Sensing. Supports multiple space temperature sensors (Up to five) for effective temperature value
(Average, Minimum, Maximum, and Smart) and options for return air sensing. Supports space and return air tem­perature, humidity, and CO2 sensing.
— Heating and Cooling Control. Provides three stages of heating and cooling for conventional equipment and up to
three compressor stages for air to air heat pumps. LCBS Connect heat pump controllers support up to two (2) stages of auxiliary heat.
— Economizer Control. Supports nine different economizer strategies that address all climatological zones in North
America.
— Dehumidification Control. Three (3) dehumidification strategies for dehumidification control are supported.
First, if the equipment is capable, a reheat mode can be programmed to provide precise dehumidification opera­tion. Second, dehumidification equipment can be controlled through a direct LCBS Connect output to provide dehumidification. Third, extended minimum cooling runtime can be selected supporting the dehumidification process.
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— Accessory Loop, Multispeed Fan Control. Each LCBS Connect controller provides the ability to configure custom
control loops to control other equipment including exhaust fans, exhaust pressurization loops, cabinet unit heat­ers, blower coils, and outdoor lighting circuits based on ambient light level. These loops are called "Accessory Loops." LCBS Controllers also provide unprecedented control of CVAHU fans that we call Multispeed Fan. This fea­ture not only ensures building occupant comfort, but when applied properly, results in energy cost avoidance to building owners.
— Honeywell Cloud Based Remote Control and Service Analytics… A New Honeywell Feature! Data is sent
securely from a building site via the internet to the Honeywell Cloud where extensive analysis is performed. The output of this analysis is useful information that will allow service contractors to do service more efficiently and effectively and retain valuable service contracts.
Background
The LCBS Connect system provides comprehensive control options for constant volume air handling units (CVAHU). In addition to heating, air conditioning, dehumidification, and ventilation applications, critical data from LCBS Connect controllers is collected, stored, and analyzed in the Honeywell Cloud. The data can be used for logging, sophisticated graphic display, advanced service alerting and "big data" analytics. Honeywell data scientists and engineers are relying on hundreds of years of control and service experience to write analytics that will help service contractors assist building owners to predict and prevent service issues from occurring, resulting in superior equipment uptime and extended HVAC equipment life. These analytics run in the cloud 24 hours a day, 365 days a year.
Honeywell has an incomparable industry reputation for providing precise temperature control, superior remote and local operator interface experience. With the addition of cloud based data collection and data analytics, Honeywell steps to the front again.
The primary focus for LCBS Connect is control of CVAHU rooftop units and split systems. Over 60% of commercial buildings in North America are heated and cooled by CVAHU packaged and split systems. The average age of this HVAC equipment is approximately eight (8) to 10 years. Due to lack of appropriate service, many suffer from operational problems including temperature, pressure, humidity sensing devices that are out of calibration, refrigeration circuits improperly under and overcharged for a variety of reasons, economizer ventilation cycles that have ceased to function, air flow systems improperly sized delivering substandard air flow, and thermostats in common buildings that "fight" each other due to improper occupant intervention.
LCBS Connect. Extending HVAC Equipment Life
The average estimated life of packaged constant volume air handling systems is about 17-25 years, depending on where the system is located. At eight (8) years, these systems are ripe for 1] restorative service and 2] re-control for reasons listed above. With service contractor assistance, a user of these systems can delay capital appropriation and expenditure by up to five (5) years by restoring these units to initial, "as built" specified operation. Restored equipment operates less resulting in lower energy costs. Ongoing maintenance costs are reduced as "tuned up" equipment operates efficiently and effectively. After this work is done, Honeywell offers LCBS Connect Cloud Services that will help HVAC service contractors keep HVAC equipment operating in a highly efficient manner and delivering extended equipment life.
What you will learn by reading this document
Each section consists of three (3) sections. First, "theory and operation" includes a short description about why we do what we do and how it works. Second, a more complete description of "how it works" is provided. Third, wiring diagrams are provided to demonstrate how an installer wires up the application. Technically, this is in the "appendix" of this document.
Controls in Small Commercial Buildings
In commercial buildings, it is essential that heating and air conditioning systems operate in a properly configured, automatic manner. In a small commercial building, HVAC operational experts are often HVAC service contractor specialists or by a few subject matter experts within the building. Additionally, control performed in a small commercial buildings is typically more complex than in a residential dwelling. Heating, cooling, fan operation, ventilation, indoor air quality, dehumidification, and various other functions can all operate successfully in a small commercial building but due to economics, we can't count on an experienced controls experts to be present to troubleshoot building controls problems.
Herein lies a point of concern for servicing contractors and building owners as we strive to effectively control small commercial buildings. Honeywell and our contractor business partners need to provide basic local control for building owners. The more power and authority that building occupants have is desirable, but can also lead to undesirable system operation, particularly higher energy use and HVAC equipment wear and tear. It is important that Honeywell LCBS Connect contractors to educate building owners about key control requirements.
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Here is a typical case of how control systems are designed to work and how building occupant's well intentioned efforts can cause facility operational problems.
Typical CVAHU systems observe a control operation strategy called "automatic heating and cooling changeover." This operation ensures that mandatory, building code compliant heating, cooling, and ventilation occurs in a commercial building. If the system permits, a building occupant can change this operational to "cooling" or "heating" only. A well intentioned building occupant may simply be hot or cold and may change settings to achieve personal comfort.
This action is not without consequences. If this setting is erroneously left in the "cooling" or "heating" position, when climate changes, mechanical heating and cooling is locked out. This will lead to an inevitable service call at 1] will cost the building owner hundreds of dollars due to service contractor interaction or 2] a service contractor who can't bill for the call due to service contractor type.
Enter LCBS Connect
A contractor that has adopted LCBS Connect will have remote access to the customer's site and will allow remote remediation of the problem and will save a truck roll to the customer's site. Providing local access to building occupants should be weighed and discussed carefully with the building owner and those paying for maintenance and utility bills.
AUTOMATIC BUILDING SCHEDULES
Automatic Occupancy Control Theory and Operation
For building owners and operators, we assume two basic things: indoor commercial building environments need to be heated, cooled, and ventilated for human health and comfort during the time humans occupy a building. There are important secondary issues relating to occupancy including management and protection of assets during periods when humans don't occupy building spaces including protection of plants, precious artwork, plumbing, paper products, and wall and floor coverings. Excessive heat, cooling, and humidity conditions can cause damage to building.
Ensuring that building space is conditioned to make sure building occupants are comfortable is quite different than making sure that it is warm or cool enough to protect plumbing from freezing and from wall paper and paint from peeling off the wall. In general, the energy required to operate systems to provide human comfort is 2-5X the cost to protect assets in a building without humans present.
How does occupancy methodology work?
LCBS Connect allows HVAC service contractor and customers to develop schedules via LCBS Connect tools including local operator interface or remote cloud based tool to match building occupancy schedules. These schedules can be also be set to accommodate occurrence of special events and holidays.
To ensure that proper comfort conditions are achieved by desired occupancy, Honeywell has developed an algorithm to meet these needs. Honeywell's answer to this recovery process is called "Adaptive Intelligent Recovery™" Implementing this correctly will require knowledge by the HVAC professional regarding the rate at which the HVAC system can provide restorative heat injection (heating), heat removal (cooling) in a building space. This recovery algorithm also keeps HVAC systems from starting suddenly and creating an excessive electrical in-rush that can result in undesirable utility demand control charges. The payoff to getting this "right" is huge. We want to keep building occupants and patrons comfortable and control energy usage and associated costs. Honeywell Adaptive Intelligent Recovery permits us to meet this requirement.
LCBS Connect controllers also have the ability to control temperature to "standby" set points. This set point technique is typically applied to building spaces that are randomly and infrequently occupied. A good example of the application of the standby set point is for an office or meeting room. The standby heating set point is always set the same or slightly below the standard occupied set point and the standard cooling set point is always set the same or slightly above the standard occupied set point. If the space temperature is being controlled at the standby set point, it is assumed that the building space being controlled is unoccupied. The benefit of using the standby strategy is twofold… 1] to make sure that building occupants are comfortable when they enter randomly occupied spaces and 2] reduce energy usage by altering HVAC control and reducing ventilation when building occupants aren't in the randomly occupied building space. The transition of standby set points from "standby" to "occupied" is typically initiated by a "motion sensor" detecting occupancy in the building space. Likewise, if the motion sensor does not detect motion, the set point is transitioned from "standby" to "unoccupied."
In order to comply with building codes, during scheduled "occupied" periods, the supply fan will run 100% on. Why? Most prevailing building codes require "continuous fresh air ventilation" and a specific requirement of fresh air, outdoor air based on an aggregate CFM per hour or CFM per person in the building space. Without going into detail, it is literally
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impossible to provide minimum fresh air ventilation without supply fan moving air. During "standby" and "unoccupied" periods, the supply fan operates in conjunction with a call for heating or cooling and ventilation is disabled, as we assume that people are not in the building space.
LCBS Connect users can permit the supply fan to run only on a call for heating or cooling during "occupied" periods, but it is discouraged and defies prevailing the building ventilation code. Further, cycling the fan on a call for heating or cooling can degrade the life of the fan motor, fan belts, and associated fan accessories.
LCBS Connect controllers have the ability to control local equipment based on an eight (8) day scheduling strategy, seven days of the week featuring four events per day and a "holiday" schedule featuring four events per day.
Let's get into some specific details.
There are four (4) programmable events that are available for each event.
— Occupied. This indicates the beginning of a time period, associated with an "on" condition or observance of "occu-
pied" set points when building occupant typically occupy building zones.
— Unoccupied. This indicates the beginning of a time period, associated with an "off" condition or observance of
"unoccupied" set points when building occupants typically leave the building.
— Standby. This indicates the beginning of a time period, associated with observance of "standby" set points, were
ventilation and fan are controlled conforming to unoccupied control behavior. Using "standby" set points and pro­cess can result in energy savings during traditional occupied hours. During the standby period, if an occupancy sensor is assigned to the controlled zone, and it detects people in the controlled zone, occupied set points and occupied ventilation practice is observed. If this occupancy sensor does not detect movement, unoccupied set points and ventilation practice is observed. Tip: Use standby set points in infrequently occupied building zones
including meeting rooms and break rooms.
— Available. This is a fourth condition indicating that a change of event state can be programmed, configured, exe-
cuted. This is also referred to as "un-configured."
How it works
Date and Time is available for each LCBS Connect controller. Each LCBS controller can support for events. For example, assume that I open my store at 7:00 AM and close it at 7:00 PM Monday through Friday. My store is open at 7:00 AM and closes at 1:00 PM on Saturday. I'm closed on Sunday. Find constructed table of required schedules below:
Table 1.
EVENT 1 EVENT 2 EVENT 3 EVENT 4
DAY
MONDAY OCCUPIED 7:00AM UNOCCUPIED 7:00PM AVAILABLE AVAILABLE
TUESDAY OCCUPIED 7:00AM UNOCCUPIED 7:00PM AVAILABLE AVAILABLE
WEDNESDAY OCCUPIED 7:00AM UNOCCUPIED 7:00PM AVAILABLE AVAILABLE
THURSDAY OCCUPIED 7:00AM UNOCCUPIED 7:00PM AVAILABLE AVAILABLE
FRIDAY OCCUPIED 7:00AM UNOCCUPIED 7:00PM AVAILABLE AVAILABLE
SATURDAY OCCUPIED 7:00AM UNOCCUPIED 7:00PM AVAILABLE AVAILABLE
SUNDAY AVAILABLE AVAILABLE AVAILABLE AVAILABLE
EVENT TYPE TIME EVENT TYPE TIME EVENT TYPE TIME EVENT TYPE TIME
Scheduling Summary
LCBS Connect controllers have a default schedule built into them. The LCBS Connect controller will work when you pull them out of the box. The default schedule is 6:00 AM to 6:00 PM Monday through Sunday. If
you want to set up different occupancy schedules, it's a good idea to refer to appropriate documentation form in your support package, print it out, and write out the schedules you want to implement. Go to LCBS Connect wall module or LCBS Connect Remote User Interface and program desired times.
Scheduling a Holiday
LCBS Connect controllers support the following holiday scenarios for one event schedule. This will be improved in the future, particularly when we implement "Cloud Based Scheduling":
Date specific: A good example of this is July 4 for our national holiday and December 25 for Christmas. This could be obvious, but isn't intended to be insulting to the reader. July 4th never changes as a date, but the day of week does.
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Day specific: A good example of this is Thanksgiving. This date is always on the last Thursday of the month of November. Thursday, as the day we celebrate American Thanksgiving, never changes, but the date does.
Extended date: Establish a specific day or date. The ability to extend this holiday any number of days is offered. For example, if we celebrate Thanksgiving and our establishment will be closed on the day following Thanksgiving, enter two (2) days in the proper configuration field.
Holiday Scheduling Summary
LCBS Connect controllers do NOT have a default holiday schedule built into them. If you want to set up different occupancy schedules on various holiday dates and times, please do so. Go to LCBS Connect wall module or LCBS Connect Remote User Interface and program desired times.
HEATING, HEAT PUMP CONTROL
Heating Theory and Operation
There are two key theoretical objectives for heating. First, we have an objective to keep building occupants comfortable by providing heat during heating seasons during periods when occupants occupy buildings. Second, we need to keep building assets warm enough so that no building damage occurs to valuable assets, particularly when it's very cold outdoors. LCBS Connect controllers are designed so they don't operate heating system in an inefficient manner, on in a manner where damage occurs to the heating systems. Some examples to protect heating equipment are minimum on and off times for gas and electric heating elements and heat exchangers, high limit heating controls, and lockout based on low sensed ambient or outdoor air temperature.
Basic Gas and Electric Heating
There are two basic systemic direct heating methods that LCBS Connect supports; standard staged heating that features natural gas heat exchangers and staged electric heat that typically include electric duct heaters. For gas heating option, LCBS Connect can either be set to energize supply fan operation on a call for heating directly or the supply fan can be controlled by a fan and limit device. The latter is quite common with gas heating systems. We support control of three stages of heat, three stages of cool. Further, electric heat can typically be cycled more frequently and aggressively than gas heat. LCBS Connect accounts for both methods and all settings.
Air to Air Heat Pump
In North America, there are areas where natural gas is not available or where electrical energy is relatively inexpensive. This makes Air to Air Heat Pumps financially and operationally viable. The air to air heat pump features mechanics and electronics that reverse the refrigeration cycle in an air conditioning unit and pumps warm refrigerant into the evaporator coil to provide heat. Another heat pump that we find in North America is the "water source" or "geothermal" heat pump. The Air to Air Heat Pump is a widely used solution that spans residential and commercial applications in North America and is the focus of this release. We will be able to control Water Source Heat Pumps and associated boiler and cooling tower plans in the 2.0 release of LCBS Connect.
A standard method of controlling the flow of refrigerant in a heat pump system is by controlling the position of the "reversing valve." There are two prevalent methods are 1] energizing the reversing valve on a call for cooling and 2] energizing the reversing value of a call for heating. For the former, the terminal designation on the low voltage terminal strip on the heat pump is "O" and for heating, "B." Please note! There is a third method of heat pump control, popularized by Carrier and Carrier brands. This method features standard Y1 and W1 cooling and heating control with the reversing valve internally controlled. It may be necessary to adjust heating minimum on times to protect heating compressor cycle.
50°F
OUTDOOR
AIR
TEMPERATURE
ADJUSTABLE
PARAMETERS
35°F
SYSTEM COMPRESSOR ONLY OPERATING
IF INDOOR AIR TEMPERATURE “DROOPS”
BELOW HEATING SETPOINT, SHUT OFF
COMPRESSOR AND USE AUX HEAT
SYSTEM FURNACE AND AUXILIARY
HEAT ONLY OPERATING
ADJUSTABLE OUTDOOR TEMP AUXILIARY LOCKOUT
ADJUSTABLE OUTDOOR TEMP BALANCE POINT
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TIME
Fig. 1.
MCR36696
LCBS CONNECT SOLUTION
Depending on the geographical location of our customer's building and of an air to air heat pump, electric auxiliary heat may be required. In northern United States, if a heat pump compressor is not protected with a compressor heater, the compressor must be locked out to prevent damage to it and electric heat must be used to heat building space. The latter can be expensive, thus we provide adjustable settings to attempt to help contractors and building owners avoid excessive electricity use. The LCBS Controller has an adjustable outdoor air limit sensor that can lockout heat pump compressor if outdoor air temperature falls below an adjustable level. Given this potential extraordinary expense, we've developed several techniques to attempt to reduce the cost of operation of electric heat. Honeywell provides an option to operate electric heat in a standard manner; this concentrates on traditional comfort. It's called the "comfort" mode. Look for this as you configure your air to air heat pump; it's a selectable option. If the building owner can tell their employees, staff to have a sweater ready on very cold days, Honeywell offers the "savings" mode. This automatically depresses the heating set point and results in electric heat cycling less, maintaining a lower heating set point.
Droop, Comfort and Saving Heat Pump Mode
What is "droop?" Simply put, it's a temperature value that "droops" below standard occupied or unoccupied heating set point. Heat pumps do a super job of heating as long as it's not too cold outdoors. As we've described a few times, sometimes the pump just loses the battle to provide adequate heating. When this happens, the LCBS Connect control system supplements the compressor and begins using "fossil fuel" heating, typically electric strip heaters. So, standard heat pump cycle is designed to terminate heat pump usage below established outdoor air temperature where the efficiency is less than electric or gas heat.
Here's a summary of the "Comfort" and "Savings" mode:
"COMFORT" MODE "SAVINGS" MODE
Depending on outdoor limits set, the compressor, the compressor acting in unison with auxiliary heat, or auxiliary heat operates to maintain heating setpoint.
COMMENTS. BENEFITS, SHORTCOMINGS
Comfort is our prevailing concern for our employees, guests, and patrons.
If "savings" mode is selected and if auxiliary heat is not locked out, the heating sepoint is depressed by "x" degrees. this minimimzes the use of auxiliary heat and avoids energy cost.
Pushes pump operation thus saves energy. the more aggressive the "savings" setpoint is, the more likely that building zones will become cold. take care to select parameters properly.
Discharge Air Temperature High Limit Control
While heating, it is possible that discharge air temperature may increase beyond an unacceptable limit. To avoid this, the LCBS Connect controller features discharge air temperature high limit control. When discharge air temperature increases above the discharge air high limit set point, the heating equipment is controlled to maintain the discharge air temperature to the set point. Let's assume that the discharge air set point is 120°F. If the discharge air temperature increases above 120°F then the heating equipment is cycled off. When it falls back below the limit minus the switching differential, it will be allowed to cycle back on. Please note: Your HVAC unit will feature a high limit heating control.
Ensure that the LCBS Connect setting is HIGHER than that of the unit being controlled.
Heating Summary
LCBS Connect controllers have a wide array of heating options. As with most functions, if you are
commissioning a simple single heat conventional system, the LCBS Controller will work "out of the box." It
will be designed to work at 68°F occupied setting and 62°F unoccupied setting. You will have access to changing proportional band, integral gain, and derivative gain if you wish. It is HIGHLY RECOMMENDED that you DON'T alter these parameters unless a Honeywell LCBS Connect support professional tells you to do so. You will need to make some basic changes to the device if you are commissioning a heat pump. There are a number of options described in this document that will allow you to alter basic heat pump operation; most are provided so that the heat pump operates in an efficient manner. It is recommended that you don't change preconfigured parameters.
COOLING, DEHUMIDIFICATION, ECONOMIZER CONTROL
Cooling Theory and Operation
There are two key operational objectives for cooling. First, we have an objective to keep building occupants comfortable during assumed cooling seasons during periods when occupants occupy buildings. A close following objective is to keep building assets cool and dehumidified enough so that no building damage occurs when it's very warm and humid outdoors. LCBS Connect controllers need to protect cooling systems so they don't operate in an inefficient manner, on in a manner where damage occurs to the cooling systems. Some typical examples to protect cooling equipment are
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ON
OFF
ON
OFF
ON
OFF
DEHUMIDIFICATION CONTROL
WORKS IN “COOLING MODE” ONLY, DOES NOT WORK IN “HEATING MODE”
TIME
HUMIDITY LIMIT, SETPOINT EXCEEDED
HUMIDITY LIMIT, SETPOINT ABATES
FAN
COOLING
HEATING
FAN ON CONTINUOUSLY (OCCUPIED, STANDBY PERIOD)
COOLING CYCLING, LOCKED ON, CYCLING
HEATING OFF, CYCLING, OFF
MCR36697
minimum on and off times for compressor operation and lockouts based on low sensed ambient or outdoor air temperature. Freeze stat operation protects HVAC system from being damaged as systems are cycled off if system freezing conditions are detected.
Cooling Operation
LCBS Connect controllers support control of compressor stages and DX refrigeration circuits. Up to three stages of cooling can be controlled by LCBS Connect controllers. There is a freeze stat sensor control input that monitors potential freezing temperatures and serves as a low limit. The sensor is typically mounted against the cooling coil and protects it from freezing, resulting in coil damage and can also make sure that unheated outdoor compressors aren't "slugged." The LCBS Connect controller shuts off the supply fan, the compressor and closes the outdoor air damper if a frozen coil condition is detected. Also the discharge air sensor utilizes a control tactic called a "low limit", where if the discharge air temperature falls below the low limit, compressor stages will be turned off until the condition goes away or all stages are off.
Dehumidification
Dehumidification Theory and Operation
Dehumidification is an important part of control operation in many parts of the United States. High humidity can result in two major problems. First, high relative humidity can result in uncomfortable conditions for building occupants. Second, relative humidity is destructive to architectural elements like carpeting, wallpaper, paint, and art work.
How does LCBS Connect dehumidification work?
Three (3) dehumidification strategies for dehumidification control are supported. First, cooling and heating can be programmed to operate in a reheat sequence to provide precise dehumidification operation. Second, dehumidification equipment can be controlled through a direct LCBS Connect output to provide dehumidification. Third, extended cooling extended runtime can be selected that can enhance and augment the dehumidification process. These are described in detail below.
Method #1. Cooling On, Cycle Heating
The reheat dehumidification control algorithm works only when system in in cooling mode. The call for dehumidification occurs as a result of humidity level rising above the dehumidification limit. If cooling is not operating, it becomes energized. A single stage of heating is energized in conjunction with the call for dehumidification. When humidity drops below set point less differential, hysteresis, the heating stage is cycled off and cooling cycles off. If a call for cooling continues, cooling remains on and cycles per temperature control algorithm. Method #1 can be augmented with Method #3, described below.
NOTE: It's important to observe the configuration of heating and cooling coils in the constant volume that you intend to
apply the dehumidification algorithm. The heating coil must be downstream of the supply fan and cooling coil for the dehumidification algorithm to work properly.
Method #2: Simple Humidification
In the "simple dehumidification method," the algorithm simply senses space or return air humidity and energizes a designated digital output until the call for dehumidification abates. Method #2 can be augmented with Method #3, described below.
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Fig. 2.
LCBS CONNECT SOLUTION
Method #3: Dehumidification extended cooling minimum run time
This alternate dehumidification sequence works in conjunction with the dehumidification strategy described above. If there is a call for dehumidification and there is also a call for cooling, the DX refrigeration will continue to operate and functionally runs for specified time. We are ensuring that a cooling stage is on long enough so that it reaches a cold enough temperature to remove moisture. This will cause fewer compressor cycles of longer duration, which may result in slightly larger temperature swings around the set point.
Cooling and Dehumidification Summary
LCBS Connect controllers have numerous cooling and dehumidification options as described in this section.
If you are commissioning a simple single cool conventional system, the LCBS Controller will work "out of the
box." It will be designed to work at 76°F occupied setting and 82°F unoccupied set point setting. You will have access to changing proportional band, integral gain, and derivative gain if you wish. It is HIGHLY RECOMMENDED that you DON'T alter these parameters unless a Honeywell LCBS Connect support professional tells you to do so. You will need to make some basic changes to the device if you are commissioning a dehumidification loop. There are a number of options described in this document that will allow you to alter basic dehumidification operation. Do not change preconfigured parameters unless you discuss this with an LCBS Connect support professional.
FRESH AIR ECONOMIZER CONTROL
Theory and Operation Economizer
There are two key operational objectives for economizer. First, we have an objective to keep building occupants alert, healthy, and safe by making sure that fresh outdoor air is continually provided to the building space. Technically, this is referred to as "ventilation." In the North American geography, there are many areas that cool, dry outdoor air can be used to cool building spaces and augment the mechanical cooling process. This apparatus, system, collection of sheet metal and controls is called an "economizer system. "
Economizer Function
Three high level strategies are supported by LCBS Connect to address control economizer functions.
— None. First, for units that do not feature integrated economizer at all, LCBS connect offers a "none" selection.
There are some parts of North America that allow make up air to be provided to building spaces in an alternate manner; not using the economizer apparatus. Please refer to ASHRAE Standard 90.1 - 2010 Section 6.5.1 or to your local building code for ventilation and economizer codes. This choice would also be used for systems that aren't connected to a fresh air, ventilation function, like many commercial split systems.
— Enable Economizer Function. Second, there are hundreds of thousands of economizers that are "controlled" by a
stand-alone collection of economizer controls, typically provided by Honeywell for the last 20 years through com­panies like MicroMetl, Cambridgeport, and Canfab to name a few. The resulting control sequence is super simple. If there is a call for cooling via a thermostat of contractor and building owner's choice and the economizer control system indicates that outdoor air is cool and dry enough, the economizer controls operate, providing as much as 100% outdoor air to cool the building space. If outdoor air becomes unacceptably warm, the electronic thermostat takes over control and controls mechanical cooling. Lastly, a time of day signal is provided to the economizer con­trol system so that the outdoor air damper is able to close 100% to avoid equipment damage and potential exces­sive energy use.
— Integrated Economizer. The third strategy that is supported is full control of the economizer function by the LCBS
Connect controller. If this option is suggested, you have also enabled the LCBS Connect controller to perform "Demand Controlled Ventilation (DCV)." DCV will be described in the next section. This is clearly the preferred selection. This results in optimum comfort for customers and can also result in efficient operation, supporting cost avoidance for building owners. Service contractors also benefit from full Cloud based remote control of the economizer function, allowing him or her to troubleshoot the economizer from the ground, rooftop unit, or their service truck.
General Economizer Operation
We refer to the economizer section of a rooftop in many ways. When we refer to the "economizer damper," we're typically referring to the combination of outside air damper and return air damper. In our area of interest in the light commercial marketplace and more specifically, 3 to 25 ton CVAHU units, the outside air damper system is typically operated by an actuator directly coupled to mechanical linkages and to dampers. The outdoor air damper is normally closed and return air damper is normally open. For most installations, the outdoor air damper is interlocked mechanically to the return air damper. The outdoor air actuator is almost exclusively a "spring return device" that is designed to "spring closed" in event of a loss of control signal power failure. The spring return apparatus in an actuator is provided to combat the potential damage to HVAC coils, compressors, and to building plumbing.
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Minimum Ventilation
Let's examine the minimum ventilation requirement first. The notion of minimum ventilation is now driven by building codes and is tied to providing "fresh air" to building dwellers. The code typically provides a guideline that is driven by number of people in a building space, multiplied by CFM per person. This is further mitigated by the operation going in the building, but that's simply too complex for this paper.
A Simple Example
We are retrofitting the controls on a five (5) ton rooftop unit in a commercial application. We are assuming that there will be an average of 20 people in the space served by this unit. Our local code dictates that we need to provide 5 CFM of "fresh air" per person to the building occupants. Our customer would like to make sure there is a rich supply of fresh air in their building space, so we'll increase this to 10 CFM per hour. Simply put, this requires us to ventilate the building space at a rate of 200 CFM per hour. The rooftop unit that we've installed has the capability to supply 2,000 CFM air per hour and further, has the capability to ventilate our space at that rate. In conclusion, we need to ventilate the space at a maximum rate of 200 CFM per hour. Divide 200 CFM by 2,000 CFM and we'll need to provide minimum ventilation rate of 10%. Don't panic! Hysteresis that occurs from damper and actuator linkage, plus the relatively poor accuracy of OEM dampers will make it easy for you to estimate 10% damper position. Use the LCBS Connect service mode to help you set the 10% air flow target.
Naturally, when folks leave the building at the end of the day, we aren't required to provide any fresh air and we close the outdoor air dampers, shut off the system fan and operate at "unoccupied set points" that result in customer energy cost avoidance.
Enable Economizer Function
There are literally millions of economizers installed in North America that are integrated through a simple integration to a time of day signal and call for cooling.
How it works. A digital "enable economize" signal must be configured on the LCBS Connect controller. Again, typically this "dry" digital output can be used to carry 24 VAC to a packaged economizer system. By definition, during building unoccupied schedule, the contact is open, disabling the economizer. This typically allows a spring return actuator to close to 100% position.
Opportunity to upgrade your customer's system and provide trusted advisor service! Using the "integrated" techniques described above, you will be able to 1] improve economizer operation 2] provide full remote access of settings, configuration information, 3] permit access to interesting and useful graphics, trending, and service mode capability and 4] enable full Title 24, economizer analytics that will allow you to provide heroic service to key service customers.
Honeywell Integrated Economizer Control Described
In addition to making sure that fresh air is provided to building occupants, the economizer function consists of two more basic control loops. First is a "mixed air control loop." This is a direct acting control loop that is enabled by a call for cooling and positions an outdoor air damper actuator based on mixed air temperature and set point. Second is a changeover or "high limit" control function. In our industry, these terms are sometimes used interchangeably. This control loop senses outdoor air temperature, or outdoor air temperature and humidity (enthalpy). If this loop senses high temperature or high enthalpy, the control system drives the outdoor air damper actuator to minimum position. The high limit controls make sure that warm or moist air is prohibited from getting into the building space.
There is another changeover strategy that is associated with the economizer function called "differential" control. On a call for cooling, if the system return air sensor senses a temperature less than the system outdoor air sensor, and a call for cooling exists, the economizer is disabled. outdoor air, I'm going to use return air to provide "free cooling." Likewise, on a call for cooling, if the outdoor air temperature is less that the return air temperature, the system economizer continues to be enabled. This is called "differential temperature changeover." There is an equivalent "differential enthalpy changeover" described in this document. Applied properly, differential control can provide substantial customer energy cost avoidance.
The test is simple… if there is a call for cooling and return air is cooler than
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WARNING
Some economizer strategies are not applicable for all climates in the United States. ASHRAE Standard 90.1 - 2010 Table 6.5.1.1.3 A describes what economizer strategies should be used in various climate regions in the United States. For example, the fixed enthalpy economizer strategy is not permitted in U.S. climate zones 1b, 2b, 3b, 3c, 4b, 4c, 5b, 5c, 6b, 7, and 8 and fixed dry bulb and differential dry bulb economizer strategy is not permitted in U.S. climate zones 1a, 2a, 3a, and 4a.
Honeywell Integrated Economizer Control, Climate Zones, Getting Tactical!
If outdoor air is cool enough, our integrated economizer system begins to control our outdoor air actuator to attempts to control to mixed air set point. The control is mitigated by a throttling range set point.
Unless you are instructed to do so by your Honeywell or LCBS Connect control system distributor, you should NEVER have to change mixed air set point and throttling range. Over 8M of the control systems we've provided to the HVAC industry have these set points "hard coded" in the devices with literally no complaints, callbacks, or service interventions.
Fig. 3.
Pacific Northwest National Laboratory & Oak Ridge National Laboratory August 2010 http://www1.eere.energy.gov/buildings/publications/pdfs/building_america/ba_climateguide_7_1.pdf
Table 2.
ASHRAE 90.1 PERMISSABLE ECONOMIZER CONTROL TYPES, HIGH LIMIT, CHAGEOVER OPTIONS
CONTROL TYPE ALLOWED IN CLIMATE ZONES HIGH LIMIT, CHANGEOVER SETPOINT
FIXED DRY BULB TEMP 1B, 2B,3B,3C,4B,4C,5B,5C,6B,7,8 OUTDOOR AIR TEMP > 75°F
5A, 6A OUTDOOR AIR TEMP > 70°F
1A,2A,3A,4A OUTDOOR AIR TEMP > 65°F
DIFFERENTIAL DRY BULB TEMP 1B, 2B, 3B, 3C, 4B, 4C, 5B,5C,6B,7,8 OUTDOOR AIR TEMP > RETURN AIR
FIXED ENTHALPY WITH FIXED DRY BULB TEMP
DIFFERENTIAL ENTHALPY WITH FIXED DRY
When the mixed air control system has captured all the cooling value from outdoor air it can, the system will begin to augment that call for cooling with mechanical cooling. An integrated low limit is also offered.
ALL OUTDOOR AIR ENTHALPY > 28
ALL OUTDOOR AIR ENTHALPY > RETURN
TEMP
BTU/LB OR OUTDOOR AIR TEMP > 75°F
AIR ENTHALPY OR OUTDOOR AIR TEMP > 75°F
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Honeywell Integrated Economizer Control - High Limit and Changeover Strategies
North America features widely different climates. ASHRAE and other code bodies recognize this fact and provide control guidance. These organizations drive application and use of economizer systems regionally. These different climate zones drive different economizer application practices. For example, air in Honolulu and Miami is far hotter, higher dew point and has almost no capability to be used to augment the HVAC cooling process.
As a service contractor, you probably know what your customer's needs are. Continue to set controls how you see fit. We haven't seen any building code or ASHRAE police roaming any U.S. streets, yet!
The information below describes the use of the following economizer strategies.
Strategy 1: Differential Enthalpy with Fixed Dry Bulb Temperature Limit
This technique can be used in all ASHRAE climate zones. Successfully applied, excellent energy savings can accrue to building owners. LCBS Connect remote services alerting and analytics can help you fine tune settings to maximize customer energy savings and maintain comfort.
How does it work? If there is a call for cooling and return air enthalpy is less than outdoor air enthalpy and the outdoor air temperature is below high limit, changeover set point, RETURN air will be used to cool your customer's building. If there is a call for cooling and return air enthalpy is GREATER than outdoor air enthalpy and the outdoor air temperature is below high limit, changeover set point, OUTDOOR air will be used to cool your customer's building.
Enthalpy hysteresis is adjustable to make sure that you don't experience excessive enabling and disabling of the economizer cycle potentially overusing the economizer actuator. It is advised that you don't change this value unless you talk to a Honeywell distributor or customer support professional.
Strategy 2: Outdoor Air Enthalpy
This technique can be used in all climate zones. HVAC professionals like this method as it's relatively simple to deploy. As with all economizer limit and changeover strategies, LCBS Connect remote services alerting and analytics can help you fine tune setting to maximize customer energy savings and maintain comfort. There is an ASHRAE prescriptive value suggestion at 28 LB/BTU changeover. Many folks find this a bit warm and could result in customer, client comfort issues.
How does it work? If there is a call for cooling and outdoor air enthalpy is less than outdoor air enthalpy set point and the outdoor air temperature is below high limit, changeover set point, outdoor air will be used to attempt to cool your customer's building.
Again, enthalpy hysteresis is adjustable to make sure that you don't experience excessive enabling and disabling of the economizer cycle potentially overusing the economizer actuator. It is advised that you don't change this value unless you talk to a Honeywell distributor or customer support professional.
Strategy 3: Differential Temperature
This technique is suggested to be used in zones 1B, 2B, 3B, 3C, 4B, 4C, 5A, 5B, 5C, 6A, 6B, 7, and 8. See map on page 16. HVAC professionals like this method as it's relatively simple to deploy and understand. As with all economizer limit and changeover strategies, LCBS Connect remote services alerting and analytics can help you fine tune setting to maximize customer energy savings and maintain comfort.
How does it work? If there is a call for cooling and outdoor air temperature is less than return air temperature and the outdoor air temperature is below high limit, changeover set point, outdoor air will be used to attempt to cool your customer's building. If there is a call for cooling and outdoor air temperature is GREATER than return air temperature and the outdoor air temperature is below high limit, changeover set point, RETURN air will be used to attempt to cool your customer's building.
Temperature hysteresis is adjustable to make sure that you don't experience excessive enabling and disabling of the economizer cycle potentially overusing the economizer actuator. It is advised that you don't change this value unless you talk to a Honeywell distributor or customer support professional.
Strategy 4: Outdoor Temperature
This technique is suggested to be used in zones 1A, 2A, 3A, 4A, 5A, 6A, 1B, 2B, 3B, 3C, 4B, 4C, 5B, 5C, 6B, 7, and 8. See map on page 16.
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HVAC professionals like this method as it's probably the simplest strategy to deploy and understand. This technique was widely used before humidity sensing technology became cost effective. As with all economizer limit and changeover strategies, LCBS Connect remote services alerting and analytics can help you fine tune setting to maximize customer energy savings and maintain comfort.
How does it work? If there is a call for cooling and outdoor air temperature is less than outdoor air temperature is below high limit, changeover set point, outdoor air will be used to cool your customer's building.
Temperature hysteresis is adjustable to make sure that you don't experience excessive enabling and disabling of the economizer cycle potentially overusing the economizer actuator. It is advised that you don't change this value unless you talk to a Honeywell distributor or customer support professional.
Low Limit Temperature Override Control
HVAC coil protection is offered as a feature as part of integrated economizer control. Please note that this feature does not work with the "simple" digital input, digital output economizer control sequence described above.
How it works. The low limit control overrides the economizer damper position to prevent the economizer control sensor, mixed air temperature or discharge air temperature from falling below the low temperature override limit by closing the economizer, outdoor air damper. The low limit temperature override control is disabled when DCV is enabled as heating will allow to cycle on.
Freeze Stat Operation
The capability to apply and install an electromechanical freeze stat as an ultimate redundant control is available. Simply select freeze stat function by configuring the appropriate digital input on the LCBS Connect controller. A freeze stat contact must be installed and an output from the device needs to be terminated to the LCBS controller. If the freeze stat is configured and the LCBS Connect controller input is closed, the CVAHU system will be shut down. The freeze stat
function can also be used to shut down the CVAHU system for smoke or fire alert, alarm.
Economizer Control Summary
LCBS Connect controllers feature an "ASHRAE Complete" range of economizer control, changeover, and
high limit options. If you are attempting to commission a "direct drive" economizer system, read this
description carefully. LCBS Connect remote services will be a great help to you as you fine tune economizer
control.
ADVANCED TEMPERATURE CONTROL FUNDAMENTALS
If you would like to learn how to "fine tune" control loops, you may want to take some time to learn about more advanced control fundamentals. This will also be important for you if you chose to construct "Accessory Loops" as part of your control business. Please read the following about proportional, integral, and derivative control operation. Contact your Honeywell LCBS Connect professional for assistance.
Proportional Control and the Concept of Differential and Throttling Range
Let's start with basic control. Feedback control uses the "error", defined as the sensed value minus the set point, to determine how to drive the output. Proportional Control commands the output as a direct proportion of the current error. This is typically configured with a "Proportional Band" or a "Throttling Range" that defines the value of the error that will result in the control output going to 100%. These terms are typical when we are describing modulating output. If we are driving a digital output, the difference that is observed between the controlled load being energized and de-energized is typically referred to as Differential.
So, if we are driving a modulating output, then the output is set to the percent calculated from the ratio of the error to the Throttling Range (TR, e.g. if the error is ½ the TR, the output would be 50%, and if the error is equal to the TR then it would be 100%).
Proportional Control
Proportional control is the function that determines the output setting required to meet the load conditions.
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THROTTLING
100%
80%
60%
40%
20%
0%
CONTROLLER OUTPUT %
70°F 72°F 74°F 76°F 78°F
EXAMPLE: COOLING – DIRECT ACTING
SETPOINT 72°F THROTTLING RANGE 4°F
RANGE
SENSOR INPUT VALUE
100%
80%
60%
40%
20%
0%
CONTROLLER OUTPUT %
70°F 72°F 74°F 76°F 78°F
EXAMPLE: HEATING – REVERSE ACTING
SETPOINT 76°F THROTTLING RANGE 4°F
THROTTLING
RANGE
SENSOR INPUT VALUE
MCR36698
Fig. 4.
A direct acting control loop is one where the output increases as the input sensor value rises above the set point. A reverse acting control loop is one where the output increases as the input falls below the set point. Direct or reverse acting should be selected based on the application requirements with the consideration that set point is the "no load" value of the measured variable and with 0% output the energy input should be the closed or off. The physical outputs can be configured to match the controlled devices (normally open, normally closed, energized on, energized off, etc.).
APPLICATION EXAMPLES
DIRECT ACTING. CONTROL DEVICE INCREASES AS MEASURED VALUE INCREASES
REVERSE ACTING. CONTROLLED DEVICE DECREASES AND MEASURED VALUE INCREASES
COOLING STATIC PRESSURE HEATING LIGHTING
DEHUMIDIFICATION CHILLED WATER PUMP HUMIDIFICATION STATIC PRESSURE
MIXED AIR CONDENSER WATER PUMP HOT WATER PUMP
The proportional calculation determines proportional error (Ep). Proportional error is the deviation from set point of the sensed medium (input sensor) divided by the throttling range expressed in units of the input sensor. The set point is the value of the input sensor at which the control loop is satisfied. When the input sensor value is at set point there is no proportional error and the output is 0%. The throttling range is the amount of change in the sensed medium required to drive the output from 0 to 100%. By definition, in proportional control the input value must deviate from set point to initiate a change in the output.
Selected Throttling Range must be narrow enough to provide good control without becoming unstable. The throttling range is determined by a number of factors such as the control application, the response time to the equipment being controlled, and the control algorithm being used. The narrower (smaller) the throttling range, the more precise the control and the wider (larger) the throttling range, the more stable the control. The objective is setting the throttling range to achieve the optimum balance between precision and stability.
Set point and Differential Refresher - On Off, Digital Control
The following is a refresher course for you and describes the relationship between set point and differential for heating and cooling. These settings are typically programmed for each control loop and each on off output.
In heating mode, the differential is below the set point. The output relay de-energizes when the temperature rises to the set point. As the temperature drops to the set point minus the differential, the relay energizes. You will also see this referred to as "direct acting," where increased control action is in direct relationship to increased temperature value.
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