Radiant heating is one of the most comfortable ways to heat a home, and throughout Marin and Sonoma counties, there are thousands of homes that rely on hydronic radiant heat every winter.

Many of these systems have been operating for decades.

At Local Plumbing, we work on radiant heating systems throughout Marin and Sonoma County, from older Eichler homes with original in-slab radiant piping to modern multi-zone systems using high-efficiency boilers, pumps, mixing valves, and smart controls.

As temperatures begin to drop around the Bay Area, now is the time to make sure your radiant heating system is ready.

Common Radiant Heating Problems

Radiant heating systems are generally reliable, but because they contain multiple components, a problem with one part of the system can affect an individual room, a heating zone, or the entire house.

Some of the most common calls we receive include:

• Radiant heat not getting warm
• Certain rooms or zones staying cold
• Boiler running but the house isn't heating
• Radiant system taking too long to heat
• Noisy pumps or piping
• Boiler repeatedly turning on and off
• Low system pressure
• Leaking manifolds or valves
• Failed circulator pumps
• Air trapped in radiant loops
• Thermostat or zone valve problems
• Older radiant piping leaking below the floor or slab

The important thing is to diagnose the entire system, rather than immediately assuming the boiler is the problem.

A perfectly functional boiler cannot heat the home properly if there is a failed circulator, closed valve, airlocked loop, control problem, or inadequate water flow.

Why Radiant Heat Repairs Require Specialized Knowledge

Hydronic radiant heating is different from conventional forced-air heating.

Instead of simply producing hot air, a radiant system has to correctly manage water temperature, water flow, system pressure, zoning, and boiler operation.

Depending on the home, the system may include:

• Boiler
• Circulator pumps
• Radiant manifolds
• Zone valves
• Mixing valves
• Expansion tank
• Air separator
• Outdoor reset controls
• Thermostats
• Heat exchangers
• In-floor or in-slab tubing

When diagnosing a radiant heating problem, we look at how all of these components are working together.

This is particularly important with older Bay Area homes where a newer boiler may have been connected to a radiant system originally installed decades earlier.

Radiant Heat Problems in Eichler Homes

Marin County has a large number of Eichler and mid-century homes that use radiant heating embedded directly in the concrete slab.

These systems can be extremely comfortable when they're working correctly, but repairing them requires experience with older radiant systems.

One concern with original Eichler radiant systems is aging metal piping beneath the concrete slab.

A radiant leak may show up as:

• Boiler pressure continually dropping
• Frequent need to add water to the heating system
• Unexplained warm or damp areas of flooring
• Higher water or energy usage
• A heating zone that no longer performs correctly

Finding the source of the problem before opening flooring or concrete is especially important.

Local Plumbing provides radiant heating troubleshooting and repair throughout Marin County, including communities with significant numbers of Eichler homes such as San Rafael, Terra Linda, Lucas Valley and surrounding areas.

Why Some Radiant Zones Stop Heating

One of the most common radiant heating complaints is:

"Most of the house is warm, but one room or zone isn't heating."

This doesn't necessarily mean there is a problem with the boiler.

Possible causes include a failed zone valve, circulator pump problem, thermostat issue, air trapped in the loop, restricted flow, manifold problem, or a control issue.

The first step should be determining whether hot water is actually being delivered through the affected radiant loop.

Replacing expensive equipment before performing this diagnosis can leave the original problem unresolved.

Radiant Heating System Pressure Problems

A hydronic heating system operates as a closed-loop system and normally maintains relatively consistent pressure.

If the boiler continually loses pressure, there is a reason.

Possible causes include:

• Expansion tank failure
• Pressure relief valve discharge
• Automatic air vent leakage
• Boiler heat exchanger leakage
• Valve or fitting leaks
• Radiant piping leaks

Continually adding water to a heating system without determining where the pressure is going isn't a long-term solution.

Fresh water also introduces additional oxygen and minerals into the system, which can contribute to corrosion and other problems.

Older Boiler With a Radiant Heating System

Many Bay Area radiant systems are still connected to boilers that are 20, 30, or even 40+ years old.

Age alone doesn't necessarily mean a boiler needs to be replaced.

However, homeowners should consider the overall condition of the boiler, availability of replacement parts, operating efficiency, reliability, venting condition, and whether repeated repairs are becoming necessary.

In some cases, repairing the existing boiler makes sense.

In others, upgrading to a modern high-efficiency boiler can improve reliability and provide much better control of the radiant system.

The key is properly designing the new boiler around the existing heating system rather than simply replacing one boiler with another.

Modern Boilers and Older Radiant Systems

Modern condensing boilers can be an excellent match for radiant heating because radiant systems often operate at relatively low water temperatures.

Lower return-water temperatures allow condensing boilers to operate at higher efficiency.

However, the installation still needs to be designed correctly.

Boiler sizing, pumping, flow rates, controls, piping configuration, outdoor reset, and water temperature all matter.

An oversized boiler or improperly configured system can result in short cycling, inconsistent temperatures, excessive equipment wear, and disappointing efficiency.

Should You Service Your Radiant Heating System Before Winter?

Fall is one of the best times to have a radiant heating system checked.

Once the first cold weather arrives in Marin and Sonoma County, heating service calls increase quickly.

A pre-season inspection gives you an opportunity to identify problems before you're depending on the system every day.

Depending on the equipment, a radiant heating and boiler service may include checking:

• Boiler operation
• Ignition and combustion
• System pressure
• Expansion tank
• Circulator pumps
• Zone operation
• Safety controls
• Venting
• Condensate system
• Radiant supply and return temperatures
• Visible leaks or corrosion

Annual maintenance is particularly important for modern high-efficiency condensing boilers.

Radiant Heat Repair in Marin & Sonoma County

Local Plumbing provides radiant heating and boiler service throughout Marin and Sonoma counties.

Our team works on both older and modern hydronic heating systems, including boiler repair, boiler replacement, circulator pumps, controls, manifolds, zoning problems, and radiant heating troubleshooting.

We regularly work in communities including San Rafael, Mill Valley, Tiburon, Sausalito, Corte Madera, Larkspur, Kentfield, Ross, San Anselmo, Fairfax, Novato, Petaluma, Sonoma and surrounding areas.

If your radiant heat isn't working correctly—or you simply want the system checked before colder weather arrives—schedule a radiant heating service with Local Plumbing.



Local Plumbing
Boiler & Radiant Heating Specialists
Marin & Sonoma County
415-484-0454