How Does Service Alerting Work; Terminal Load, Zone Demand Alert; Space Humidity Alert - Honeywell LCBS Applications Manual

How does service alerting work?

The service provider can select any analog sensor to provide alert information. Further, alerts are provided for all sensors
attached to the system that fail by short or open conditions. Alerts are also propagated if controllers fail and if the system
gateway fails. Analog alerting is described below, followed by these other cases. During the selection of these sensing
options, it's important to understand why alerting is necessary and what we are prepared to do if an alert is triggered. This
drives very specific documentation that we will prepare to address and alert.
NOTE: We don't necessarily need to alert on every analog point, in fact, setting up copious alerts that are poorly
conceived, can cause more problem than good. Our recommendation is to start with a few, carefully selected
alerts with very specific, viable requirements and expected outcomes.
First, consider some key service failures, events, key personnel that can impact how you perform against your service
contract objectives. Who is signing your checks for your service agreement? Who needs to be kept comfortable at your
customer's place of business? What is the impact to them if comfort conditions aren't provided? How old is the equipment
that you service? Did you just perform some repairs on equipment that you need to "keep an eye on," that you suspect may
fail? After you have this discussion with you and your staff, it would be good to write your thoughts down on
accompanying form. Your Distributor or Honeywell sales professional is available to help you as well.
Here are some examples shown below that will help you with develop your own meaningful alerts.

Terminal Load, Zone Demand Alert

This is one of many analytics that will tell a service contractor if heating and cooling equipment is matching zone,
space demand. A high terminal load, zone demand reading at 130% (max 162%) or above indicates that
mechanical cooling is not matching zone, building heat exchange demand. Likewise, a low terminal load, zone
demand of -130% (min -162%) or lower indicates that mechanical or electric heating is not matching zone,
building heat exchange demand.
Your story
You have a maintenance contract with your customer to monitor heating and cooling efficiency. If you receive and alert
for 120% for cooling or -120% for heating, you are beginning to lose capacity for some reason. This could be a result of
heat exchangers that are getting dirty and losing efficiency. This could also be a result of a malfunctioning economizer, a
loss of refrigerant charge, a dirty condenser or failed condenser fan. This is your opportunity to address this issue before
it gets "out of control" status. Think about this one... if you get this alert during the Fall or Spring season before
requirement for heating or cooling gets more substantial, you better do something about it before it gets very cold or very
warm.
NOTICE
Design considerations. You should apply terminal load, zone demand alerts at 125% or -125% for cooling and
heating respectively. When a system reaches this level, temperature control becomes impaired. Create a custom
message and make sure that your service technician gets a custom e-mail message and an SMS message. The
messaging could result in some well timed service.

Space Humidity Alert

Space humidity levels are usually a good sign that cooling systems that you observe and service are not performing
properly.
Your story
Your service a client that is putting off replacement of a 20 year old rooftop unit. You've done everything you can to keep
the unit operating. Your customer knows that the unit is on it "last legs" and that they want to put off the decision to
replace the unit until next year; the next cooling season.
You have observed that the unit isn't holding a proper refrigerant charge and that further, the unit does a poor job of
dehumidification as the equipment has aged. When you serviced the unit last time, you found that the dry bulb
temperature is being maintained properly, but space humidity was pretty high. So, based on this, you've decided to
monitor the unit and have picked space humidity as one of the points you will monitor. This is a great choice because
humidity is included in the standard LCBS Connect controller wall module.
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