Multiaqua question

[liquid sky]

Alright, I'm not an HVAC pro, but at least I am an electrician and have done my share of HVAC-related electrical work. Planning to eventually have an HVAC ticket too. Anyway, I had a question about Multiaqua systems. I like the idea and have been trying to inform myself about them.

One thing is unclear to me though: is the circulator pump ALWAYS running unless power to the chiller is cut?

I mean, if you had a 2-pipe system, cooling only, and had 8 zones, yet none of the zones were active...what does the chiller do in this situation? The pump keeps pushing water around 24/7 even though nobody is using any? If the LWT rises above the setpoint differential, just from sitting around doing nothing, the compressor cycles on and chills the whole loop again? How would you eliminate this waste of pumping energy?

Thanks

[liquid sky]

[liquid sky]

Controls.

Oh yeah? I would never have guessed.

These things don't appear to have a means for the individual zones to control the chiller. Their fan coils only operate a zone valve. The chiller obviously only cares about maintaining loop temperature, and none of their documentation indicates a means to turn on and off the water pump. It looks like the pump runs forever until the temperature rises enough to start the compressor.

For larger capacities they suggest connecting several chillers in parallel but there is no central control that decides which chiller is powering up at what time, or a way to stage the startup so that multiple compressors don't all draw inrush current at the same time.

[Nuclrchiller]

Look at the building controls. Typically there will be a means of starting and stopping the pump on a schedule and/or disabling the chiller. Is this used for process cooling or comfort cooling?

[liquid sky]

Look at the building controls. Typically there will be a means of starting and stopping the pump on a schedule and/or disabling the chiller. Is this used for process cooling or comfort cooling?

There are no building controls...these are baby sized chillers with a built-in pump mostly intended for light commercial and resi A/C, although it looks like they can be used for process cooling too. 3, 4, 5 and 10 tons.

The internal temperature control only has one NO and one NC contact, to cycle the compressor on and off.

http://www.multiaqua.com

[Nuclrchiller]

Are you asking about these chillers, in general? Or about a specific chiller at a specific site? If in general, field-installed controls that are properly designed and installed are crucial to proper operation of any chiller. You have already discovered that for yourself. If they were simply "plug and play" a lot of us here would have more free time on our hands!

[beenthere]

kirkH, and rad1, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

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[ralphferia]

This is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

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[beenthere]

ralphferia, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

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