In-Floor Radiant Heating No Heat: Diagnosis & Repair in Greater Vancouver

Nothing is more frustrating on a cold, wet Vancouver evening than reaching down and finding a floor that should be warm sitting stone cold. In-floor radiant heat feels wonderful when it works, and it feels like a mystery when it does not, because the pipes, manifold, pump and controls are all hidden behind drywall, under tile, or inside the mechanical room. The good news is that a "no heat" radiant call almost always traces back to one of a handful of known failure points, and most of them are repairable without tearing up a floor.

ROMA Heating & Cooling has diagnosed and repaired hydronic radiant systems across Vancouver, Burnaby, Richmond, Surrey and the Tri-Cities since 1999. We are a TSBC-licensed gas contractor, gas licence LGA0202903, with Red Seal-trained technicians who understand the whole system, boiler, pump, manifold and thermostat, not just the visible parts. Call ROMA at (604) 704-0300 for a diagnosis.

Start with what the system is doing

Before opening anything up, it helps to note exactly what is happening: is the whole house cold, or just one zone? Does the boiler fire at all? Is there any warmth at the manifold pipes, even a little? Does the thermostat display show it is calling for heat? Those few observations point a technician toward the right branch of the system immediately, whether that is the control side, the manifold, or the boiler itself.

Where a radiant no-heat problem usually starts

📞 Talk to a licensed ROMA radiant heating technician — (604) 704-0300

Thermostat or sensor not calling for heat

If the thermostat is not sending a call, nothing downstream will run. A dead battery, a tripped breaker feeding the low-voltage transformer, a bad in-floor sensor, or a thermostat set to the wrong mode can all leave a perfectly healthy system sitting idle. This is one of the few checks a homeowner can safely make before calling.

A stuck or failed zone actuator

Each loop at the manifold has a thermal actuator that opens the zone valve when its thermostat calls. Actuators fail closed often enough to be the single most common cause of one cold zone in an otherwise working system. A technician can test and swap an actuator quickly once the fault is confirmed.

A closed or fouled zone valve at the manifold

Under the actuator sits the valve itself, and on older systems, or where mineral scale from Greater Vancouver's harder water has built up, the valve can seize. If the actuator tests fine but the loop still will not open, the valve is the next suspect.

Air trapped in the loop

Air pockets at the manifold or in a loop block water flow even when every valve and actuator works correctly. This is common after any work on the system, a drained boiler, or a slow weeping leak that lets air in over time. Purging at the manifold isolation valves usually restores flow.

A failed or seized circulator pump

If nothing in the house is warm, not just one zone, the circulator pump is a prime suspect. Pumps can seize, lose their capacitor, or simply wear out after years of continuous run time, and a system with no circulation cannot deliver heat no matter how well the boiler is firing.

A boiler-side fault

Sometimes the radiant loops and manifold are perfectly healthy and the real problem is upstream: the boiler is not firing, an outdoor reset or mixing valve is holding supply water too cool, an aquastat is misreading, or an ignition fault has locked the unit out. Because radiant systems often share a boiler with domestic hot water or another zone, we check whether those are also affected, which narrows things down fast.

Why Vancouver homes see more of these calls

Greater Vancouver has a lot of older character homes and converted heritage properties where a hydronic radiant system was added years after the original boiler, sometimes sharing that boiler with baseboards or domestic hot water in ways that make diagnosis trickier. Harder water in parts of the region also speeds up scale build-up inside valves and manifolds compared with soft-water areas, and mild, damp winters mean systems often sit idle for long stretches in shoulder season before being asked to work hard on the first cold snap, which is exactly when a weak pump or a stuck actuator tends to show itself.

Repair versus a controls or pump upgrade

Most no-heat calls are a straightforward part repair: an actuator, a valve, a pump, or a purge. Where we see repeat failures, tired zone controls, or a pump that keeps failing, it is often more cost-effective over the life of the system to replace the aging component with a modern equivalent than to keep patching it. Cost always depends on what is actually wrong, the age and brand of the equipment, and how accessible the manifold and pump are, so we diagnose first and quote clearly before any work begins, with no guessing and no hidden fees.

Radiant no-heat symptoms, likely causes, and what ROMA does

How ROMA diagnoses a radiant no-heat call

We work the system in a logical order rather than guessing part by part. First we confirm the thermostat is actually calling for heat and that power reaches the transformer and controls. Next we check the boiler itself, is it firing, is it locked out, is the supply water actually hot. From there we move to the manifold, testing each actuator and valve, checking for warmth at every loop, and purging air where flow seems restricted. If the boiler and manifold both check out but a zone still will not warm, we look at balancing and, on older systems, at scale or debris inside the loop itself. This sequence usually isolates the fault within one visit, and it means we are not swapping parts on a guess.

Homeowner-safe checks first

Before you call, it is safe to confirm the thermostat has power and is set to heat, check that the breaker feeding the boiler and any transformer has not tripped, and glance at the boiler display for an obvious fault code or lockout light. Do not open the manifold, adjust balancing valves, or attempt to bleed the system yourself, sealed hydronic components and boiler controls are for a licensed technician. If you ever smell gas, leave the home and call the FortisBC emergency line and 911 from outside; if a carbon monoxide alarm sounds or anyone has headache or nausea symptoms, get everyone out and call 911.

Why Vancouver homeowners choose ROMA

ROMA Heating & Cooling has served Greater Vancouver from Burnaby since 1999, restoring radiant heat in character homes, townhomes and strata units from Vancouver and North Vancouver to Coquitlam, Surrey and Langley. You get licensed, Red Seal-trained technicians, gas licence LGA0202903, upfront flat-rate pricing with no hidden fees, and a 4.8-star rating from 221 Google reviews, with service seven days a week. Call ROMA at (604) 704-0300 or book a free estimate online. See our boiler repair and boiler services, protect the system with a maintenance plan, and guard against scale with boiler cleaning.

Frequently Asked Questions

Why is one radiant zone cold while the rest of the house is fine?

Almost always a stuck thermal actuator or a seized zone valve at the manifold for that loop, sometimes trapped air. ROMA tests the actuator, valve and airflow to confirm the exact cause before replacing anything. Call (604) 704-0300.

Why is my whole in-floor radiant system not heating at all?

When every zone is cold, the problem is usually upstream of the manifold: the boiler is not firing, or the circulator pump has failed or seized. ROMA checks the boiler and pump first when the whole house is affected.

Can trapped air really stop a radiant zone from heating?

Yes. An air pocket at the manifold or in a loop blocks water flow even when the valve and actuator are working correctly. Purging the loop at the manifold isolation valves typically restores full heat.

How do I know if it is the thermostat or the actuator?

If the thermostat display is blank or not calling for heat, the fault is likely electrical, power, wiring or the sensor. If the thermostat is calling correctly but the floor stays cold, the actuator or valve at the manifold is the next suspect.

When does a no-heat radiant problem mean I need a new pump or controls, not just a repair?

If a pump or zone control keeps failing repeatedly, replacing the aging component is often more cost-effective long term than continuing to patch it. ROMA diagnoses first and gives a clear quote before recommending replacement.

Reviewed by the ROMA Heating & Cooling team — TSBC-licensed gas contractor (Gas LGA0202903), serving Greater Vancouver since 1999. Updated July 2026.