The Glitch & The Fix

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When only the air handler is operating the heat pump is able to supply the 120 ºF water. However, when the floor heating zone and the air handler are operating at the same time and the outdoor air temperature is below 24 ºF the fluid temperature leaving the heat pump can’t climb above 103 ºF. Why is this happening, and what can be done?

Can you spot several details that are either incorrect or missing? Can you propose an alternative design that would accomplish the same goals using less hardware?

A heating contractor is installing two air-to-water heat pumps as the primary heat source in a large home's hydronic system, keeping the existing boiler as backup. However, problems like heat migration into off zones and corrosion of the vent connector suggest design flaws that need to be addressed.

Occupants of a building using a hydro-split air-to-water heat pump are facing slow recovery after night setbacks and inadequate hot water during peak demand. The system, composed of an outdoor and indoor unit, struggles with heating efficiency. What improvements could enhance its performance?

The first photo shows an oil-fired boiler and surrounding details. Take a close look, and make a list of what you would change in this portion of the system.

The photo in Figure 1 shows a non-pressurized outdoor wood-fired furnace connected to a floor heating subsystem via two PEX tubes. It includes a cast iron circulator, a thermostatic 3-way valve for mixing, a bypass linking supply and return tubes, and an "expansion zone" for another floor heating circuit. This setup is in a multi-million dollar home. Are there any potential issues with the installation?

A project needs medium- and low-temperature radiant floor panels. The installer proposes using a mod/con boiler with a 1-inch tempering valve for lower temperatures and plans to pipe the entire system with 1-inch tubing. What potential issues could arise from this design?

The two photos below were from the same project. Flow is upward through the vertical pipe in Figure 1. Without any more details being described, can you spot at least two problems in each photo?

Due to its low efficiency and high emissions, an installer is asked to replace the outdoor wood-fired furnace with a new cordwood gasification boiler.

Take a look at the two photos in Figure 1. Do you see any installation practices that might compromise the eventual structural or thermal performance of this slab?