Troubleshooting Cold Spots in Your Radiant Floor Heating

Why Are There Cold Spots in My Radiant Floor?

Cold spots in a radiant floor heating system are one of the most common complaints homeowners have. The good news is that most causes are straightforward to diagnose and fix.

Common Causes & Solutions

1. Air Trapped in the System

Symptoms: Gurgling sounds, certain zones not heating, inconsistent temperatures.

Solution: Air pockets block water flow through the PEX tubing. Your system needs to be purged:

• Locate the manifold (usually in a utility room or basement)
• Open the purge valves one zone at a time
• Run water through until no air bubbles appear
• Close valves and check system pressure

2. Incorrect Flow Balancing

Symptoms: Some rooms are too hot while others are cold.

Solution: Each zone on your manifold has a flow meter or balancing valve. Zones with longer tubing runs need more flow. A technician can adjust these to ensure even distribution.

3. Thermostat or Sensor Issues

Symptoms: Floor temperature doesn't match thermostat setting.

Solution:

• Check that the floor sensor is properly installed and reading correctly
• Verify thermostat batteries (if wireless)
• Ensure the thermostat is set to "floor" mode, not "air" mode

4. Insufficient Insulation

Symptoms: Floor heats slowly, high energy bills, heat loss to basement/crawlspace.

Solution: If there's no insulation below the tubing, up to 50% of heat can be lost downward. Adding rigid foam insulation beneath the subfloor dramatically improves performance.

5. Boiler Temperature Too Low

Symptoms: Floor is warm but not hot enough, takes hours to reach temperature.

Solution: Check your boiler's supply water temperature:

• Tile/stone floors: 100–120°F
• Hardwood floors: 80–95°F (max 85°F for most manufacturers)
• Concrete slab: 110–140°F

When to Call Radiant Technology

Contact us if you experience:

• Cold spots that persist after purging
• Visible water leaks near the manifold
• Boiler error codes or shutdowns
• Significant pressure drops in the system
• Any zone that completely stops heating

Serving all of Orange County, NY. Call (845) 800-9119 or submit a support ticket [blocked] for fast assistance.