Whole Building Hydronic System

Can anyone explain these to me? I understand how they would send warm water through the coil in the winter and cold water in the summer. Did a unit yesterday where both the heat and the cooling system seemed to work. How could both the chiller and the hot water be hooked up at the same time?

Also, starting to see Sharkbite flex tubes on water heaters. I see Sharkbite makes them specifically for water heaters so they are OK?

Any photos???


Yes on the water heater connectors.

On your hydronic system, pictures or a drawing is the only way we can help you.

Systems may be isolated - heating source and a chiller each with its own separate coil in the same ducted system.
Or… Three way solenoid valves.

Reminder - chillers are piped very similar to a boiler system so look closely.

Interesting. I’ve never seen hydronic cooling.

Frank …

Water to Air Heat Pumps can be considered hydronic I suppose (especially if connected to a chiller)??

OR ground source heat pumps, etc

My only experience with hydronic systems is tubing in the slab, or in gypcrete on framed floor, zoned and heated with a boiler.


Check out Multi-Aqua chillers. Solution/water to air and piped just like a boiler (reverse return).

Is it a 4 foot tall panel with copper tubes inside and a blower ?
It may be a 4 pipe ambient system.

You can run both at same time and extremely common.

If you got both heating and cooling out of it, then this sounds like a single-fluid, two-pipe, water-source heat pump system. You’re in the right climate for it. They work well. Here’s a photo of one. This one operated with a cooling tower during the summer, and a gas fired hydronic boiler in the winter. Loops can work two ways: 1) either with a closed building loop and open cooling tower loop (interface is a plate and frame exchanger) and a hydronic boiler installed in the closed loop (and shut off in winter), or 2) with a single open loop and cooling tower, with a bypass to a hydronic boiler in the winter.

Or, what you saw was a two-pipe fan coil system with a single thermal fluid loop, with chilled water in the summer and hot water in winter. These loops work in three ways: 1) cooling-only, 2) heat-only in cold weather, 3) free-cooling mode in the fall and spring (if there’s a cooling tower present). But you couldn’t get both heating and cooling out of it unless it was a four-pipe system.

Four pipe systems are exactly that: supply and return chilled water, supply and return hot water.

Another possibility is a water-source DX unit with electric heat coils. Or a chilled water fan coil unit with electric heat coils. A photo of the dataplate would settle this.