What's the definition of percentage in a zone, and what is it used for?

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anibal
Posts: 4
Joined: Mon Nov 16, 2020 4:25 pm

What's the definition of percentage in a zone, and what is it used for?

Post by anibal »

Hi all,

I'm new to EWC Controls, and just setup a system based on two UT3000, using 6 Honeywell VisionPro8000 thermostats all controlled via a RedLink Internet Gateway (actually 2 of them - since they have a limit of 4 items per gateway - go figure).

My contractor, who sold me the system and is setting it up, it's not giving me a straight answer with respect to percentages. There's a configuration in the UT3000 where you can configure the % for each zone. What is this percentage meaning and what does it control?

I'd love to hear the actual definition and also real-world examples of different settings and why they were chosen like that. Posting a picture here of my setup for fun.
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Tony
Posts: 1
Joined: Fri Nov 20, 2020 8:27 am

Re: What's the definition of percentage in a zone, and what is it used for?

Post by Tony »

Dear Anibal,
that is a great question. When we talk about % of each zone we mean , the board assigned each zone a weight, the sum of all these weights together = 100%, total system. we use this when thermostats call, and apply a formula.
Zone weight x thermostat demand / 100 = initial system demand.

Zone 1 = 70% assigned weight .70 x thermostat demand of .30 = a 21% system demand. that thermostat wants 21% of what that compressor can do.

Hopefully that helps you understand the process.
If you still have an application specific question, give us a call, and we will gladly explain what the board is doing for you..
x490
Thank You,
anibal
Posts: 4
Joined: Mon Nov 16, 2020 4:25 pm

Re: What's the definition of percentage in a zone, and what is it used for?

Post by anibal »

Hi Tony,

Thanks for the prompt response!

What do you mean by the "thermostat demand"? What would a thermostat demand of .30 mean?

Thanks,

-Anibal
anibal
Posts: 4
Joined: Mon Nov 16, 2020 4:25 pm

Re: What's the definition of percentage in a zone, and what is it used for?

Post by anibal »

Follow-up question/scenario.

I have two rooms, each in its own zone, both serviced by one furnace/HP.

One room, let's call it Office, is at 25C, while the other, let's call it Noah's, is at 20C. The set point is 21C for both. What does EWC do in this case? It can only send heat or cold, but not both heat and cold at the same time. So, what would the EWC instruct the machines to do to get to 21C?
John B.
Posts: 20
Joined: Fri Mar 13, 2009 8:57 am

Re: What's the definition of percentage in a zone, and what is it used for?

Post by John B. »

Anibal,

The UT3000's PID loop and zone weighting features are a means of insuring that any zone can receive the proper BTU capacity. As Tony pointed out, there's some math involved but it's not complicated.

You don't have communicating thermostats, so the UT3000 will always interpret your thermostat heat/cool demands as 100%. In a given scenario of zone assigned weight value, that weight value will be multiplied by 100% (1.0).

ie. 30% weight x 1.0 = 30% "initial" system demand to the HVAC system for heating or cooling operations.

Immediately afterwards, the PID loop kicks in (if enabled) which allows the UT3000 to ramp/stage the HVAC system (above 30%) in an attempt to hit the supply air sensor temperature target. This is described in detail in the Technical Bulletin.

Please call me to discuss in further detail.

John
John Brown :geek:
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