Boiler Repair in Glen Ellen: Get Your Radiant Heat Ready Before the Cold Sets In
Fill valves, low pressure, and no hot water: what to fix before winter
Glen Ellen nights drop fast once October arrives, and the first cold morning is when a lot of boilers show their problems. If your radiant floors are slow to warm, your boiler keeps locking out, or your hot water has gone lukewarm, call or text Local Plumbing at (415) 234-0370 and we'll get it sorted before the heating season really starts.
We've been out in Glen Ellen and around Sonoma Valley a lot over the past couple of weeks. The calls look familiar: a fill valve that stopped keeping the system at pressure, a boiler that heats the house but won't make domestic hot water. Here's what those symptoms usually mean, and what's worth doing now.
Why Glen Ellen Boilers Have Their Own Quirks
Heating in Glen Ellen isn't one-size-fits-all. Within a few miles you'll find:
- Rebuilt homes after the 2017 fires with newer high-efficiency condensing boilers, radiant slabs, and sometimes a combination of radiant floors and an indirect water heater. The equipment is newer, but many of these systems are now 6–9 years old and hitting their first round of wear parts.
- Older ranch homes and cabins along Arnold Drive, off Warm Springs Road, and up toward Sonoma Mountain Road, some with cast-iron boilers and baseboard or retrofitted radiant zones.
- Estate and vineyard properties with long pipe runs, multiple buildings, and several zones.
- Well water on many properties outside town. Hard or mineral-heavy fill water shortens the life of fill valves, heat exchangers, and plate exchangers on combi boilers.
Big daily temperature swings in the valley also mean your boiler cycles more often in the fall and spring than a similar system near the coast.
The Fill Valve: Small Part, Big Symptoms
Every closed hydronic system has an automatic fill valve (a pressure-reducing valve) that keeps the loop topped up. When it fails, you'll see one of two things:
It stops feeding. Pressure slowly drops as tiny amounts of air or water leave the system. Once the gauge falls below about 12 PSI, many modern boilers lock out on low pressure, and upper floors or the farthest zones go cold first.
It over-feeds. Pressure creeps up until the relief valve starts dripping or discharging. That's a warning sign, not something to ignore. It can also point to a failed expansion tank.
Mineral buildup from well water is a common reason fill valves stick. Replacing the valve is a routine repair, but we always check the expansion tank and relief valve at the same visit. A failed fill valve is often a symptom of a bigger pressure problem.
"The Heat Works, but There's No Hot Water"
Many Glen Ellen homes use one boiler for both radiant heat and domestic hot water, either as a combi boiler (like a Navien NCB) or a boiler feeding an indirect tank. When hot water stops but the heat still works, the usual causes are:
- A failed or stuck three-way diverter valve or zone valve that sends heat to the floors but never to the tank
- A scaled plate heat exchanger on a combi boiler, especially on well water
- A bad tank sensor or aquastat on an indirect water heater
- A failed circulator on the indirect loop
These are usually repairable. An 8-year-old boiler with a hot water problem is rarely a replacement candidate on that symptom alone.
Warning Signs to Watch for This Fall
Call us if you notice any of these:
- Pressure gauge below 12 PSI, or relief valve dripping
- Kettling, banging, or gurgling from the boiler or in the floors
- Radiant zones that take all day to warm, or one zone that never does
- Error codes or repeated lockouts on Navien, NTI, HTP, Lochinvar, or Viessmann boilers
- Water at the base of the boiler or around the condensate line
- Hot water that runs out quickly or never gets hot
Repair or Replace?
We'll give you a straight answer. For most Glen Ellen systems we see, repair and maintenance make sense: fill valves, expansion tanks, circulators, sensors, and a proper cleaning keep a well-installed boiler running for many years.
Replacement starts making sense when:
- The heat exchanger is cracked or leaking
- Parts are discontinued (Triangle Tube owners, read our post on the Triangle Tube shutdown)
- The boiler is 15–20+ years old and needs repeated repairs
- The system was badly designed from the start and never heated evenly
If you're weighing it up, we'll show you what we found and let you decide.
What Our Boiler Service Includes
Every tune-up and repair visit includes:
- Combustion analysis to set the gas-to-air ratio correctly
- Heat exchanger and burner inspection and cleaning
- Condensate trap and neutralizer cleaning
- Expansion tank, fill valve, and relief valve checks
- Circulator, zone valve, and control checks
- A radiant manifold and system pressure check, including glycol where it's used
We're hydronic specialists, not just general plumbers. Our team trains at our warehouse and training facility in San Rafael, and we service Sonoma Valley regularly. See our boiler repair and radiant heating repair pages for more.
Glen Ellen Boiler FAQs
Why does my boiler pressure keep dropping?
Usually a failing automatic fill valve, a small leak somewhere in the loop, or an air vent that's letting water out. A slow drop over days or weeks is worth diagnosing before it turns into a lockout on a cold night.
Is it normal for my relief valve to drip?
No. A dripping relief valve usually means system pressure is too high, often from a failed expansion tank or an over-feeding fill valve. Get it checked.
How often should a boiler in Glen Ellen be serviced?
Once a year, ideally in early fall before heavy use. High-efficiency condensing boilers need annual cleaning, and most manufacturers require documented maintenance for warranty.
Does well water affect my boiler?
It can. Hard or mineral-heavy water scales fill valves and the domestic hot water side of combi boilers faster. We'll check for buildup during service and tell you if water treatment is worth considering.
Serving Glen Ellen and All of Sonoma Valley
Local Plumbing services boilers and radiant heat throughout Glen Ellen, Kenwood, Sonoma, Boyes Hot Springs, and the rest of Sonoma Valley, plus Marin and Napa. If your system needs a tune-up or isn't keeping up, call or text (415) 234-0370 or contact us online to schedule.
