Heating & furnace repair –
We fix the real problem. Same Day.
A furnace failure in a Central Valley cold snap is not something you wait a week for. Grandmark’s licensed technicians diagnose and repair all major heating systems across all 5 California markets. Video-documented. $0 down financing. Fix it or you don’t pay.
Don’t let budget timing delay a heating repair in winter
A heating failure in California’s winter doesn’t give you time to plan a budget. Every hour without heat in freezing temperatures compounds the urgency. Financing removes the financial reason to delay.
$0 down · 0% interest · 18 months
Available on all heating repairs and replacements. Same-day approval — no hard credit pull to check eligibility. No early payoff penalty.
Our Lifetime Guarantee – Zero Risk
f we diagnose your heating repair and fix it, and the same problem comes back — we make it right at no charge. We stand behind every repair we complete.
— Grandmark Service Company · Applies to all residential and commercial Heating repairs across all 5 California markets.
Here’s what most California homeowners experience before calling us:
Because we don’t patch symptoms. We fix causes. When you repair the right thing the right way, the problem stays fixed.
We Show You Exactly What’s Wrong — On Video — Before We Touch Your AC
No guesswork. No mystery invoices. No surprise “we found something else.
Mckay did a great job on the repair work. He also was professional and friendly. Thank you!!!!
Tom Lingenfelter
Fresno, CA
Romelo is the best ! He came to my home took his time to find out why my Ac wasn’t working and found out I had a leak in one of my units . He was very nice and understanding!
Sabrina Sanchez
Sacramento, CA
Excellent customer service. David López explained the procedure very well and answered all our questions. They are fast and efficient. 100% recommended.
Elyzabeth Ramirez
Bakersfield, CA
We diagnose the real cause — show you on video — and assess carbon monoxide safety on every call.
Video-documented diagnosis
Every heating diagnosis is recorded on video — the failing component, the test readings, the safety assessment findings — before quoting a single dollar. You see exactly what we find. No other heating company in California does this as standard
Carbon monoxide safety — every furnace call
A cracked heat exchanger in a gas furnace can allow carbon monoxide to enter living spaces — a life-safety issue that has no symptoms until it’s too late. We assess CO risk on every furnace service call as standard procedure. Not optional. Not an add-on. Standard.
Root cause diagnosis — not part replacement
We diagnose why the igniter failed, why the flame sensor fouled, why the heat exchanger cracked. A part replaced without understanding why it failed is a temporary fix. Every Grandmark repair addresses the cause — which is why our guarantee means something.
Fix it or you don’t pay
Same problem comes back after we repair it — we return at no charge. No argument. No invoice. Every heating repair across all 5 California markets — residential and commercial.
We Fix the Problem. Or You Don’t Pay. That’s Not Marketing — That’s Our Policy.
If we diagnose your system and fix it, and the same problem comes back — we make it right at no charge. We stand behind every repair we complete. Not because we have to. Because we want to be the company you call when it’s time for a full replacement
Every type of heating repair — diagnosed and fixed right
Igniter failure
The igniter lights the burner in your gas furnace. When it fails, the furnace attempts to start, can’t ignite, and shuts down on safety lockout. One of the most common furnace failures in California.
Flame sensor fouling
The flame sensor confirms the burner is lit before allowing gas to flow. When it becomes coated with residue common in California’s dusty environments — it can’t detect the flame and the furnace shuts off on safety lockout.
Heat exchanger inspection
The heat exchanger separates the combustion gases from the air distributed through your home. A crack allows carbon monoxide to enter your living spaces. A cracked heat exchanger means the furnace must be shut down until repaired or replaced.
Gas valve diagnosis
The gas valve controls gas flow to the burners. A failing gas valve causes the furnace to not ignite, to ignite intermittently, or to produce reduced heat output. Gas valve diagnosis requires proper testing equipment and licensed technician experience — not a visual inspection.
Blower motor repair
The blower motor circulates heated air through your duct system. A failing blower causes insufficient heat distribution, overheating of the heat exchanger, and ultimately furnace shutdown on high-limit safety.
Control board diagnosis
The control board manages every function of your furnace ignition sequence, blower speed, safety limit monitoring, and error code communication. Control board failures are often misdiagnosed as component failures.
Heat pump heating diagnosis
Heat pumps provide heating by moving heat from outdoor air into your home. When outdoor temperatures drop, heat pump efficiency decreases and the defrost cycle becomes critical.
Draft inducer and venting
The draft inducer pulls combustion gases through the heat exchanger and vents them safely outside. A failing inducer motor or blocked flue creates a backdraft condition pulling combustion gases back into the living space.
Six signs your heating system needs repair now — not later
Furnace running but no heat coming out
The furnace starts, the blower runs, but the air coming from your vents is cold or room temperature. Most common causes are a failed igniter, a fouled flame sensor, or a gas supply issue — all of which get worse the longer the system runs without diagnosis.
Furnace starts then shuts off after a few minutes
The furnace ignites, runs briefly, then shuts off before the home reaches temperature. This is called short cycling — usually caused by a tripped high-limit safety switch, a cracked heat exchanger, or a blocked flue. Short cycling on a furnace is never normal and always needs diagnosis.
Unusual noises — banging, rattling, squealing
A properly functioning furnace operates quietly. Banging at startup indicates delayed ignition — unburned gas igniting in a small explosion inside the heat exchanger. Rattling suggests a loose component. Squealing is a blower motor bearing. Every one of these gets worse with every cycle.
Electricity or gas bills spiking unexpectedly
A furnace losing efficiency — from a dirty heat exchanger, a failing inducer motor, or a degrading burner — runs longer to produce the same heat output. If your gas bill has increased significantly with no change in usage patterns, the furnace is working harder than it should be.
Furnace over 15 years old with no recent service
A furnace over 15 years old that hasn’t been serviced is not a question of if it will fail — it’s when. Heat exchangers in older furnaces are at elevated risk of cracking. Capacitors, igniters, and flame sensors all degrade over time. An inspection now costs far less than an emergency replacement in January.
Yellow or orange burner flame instead of blue
A healthy gas burner produces a steady blue flame. Yellow or orange flame indicates incomplete combustion — which means carbon monoxide may be present. Turn the furnace off and call immediately. Do not run a furnace with a yellow or orange flame.
FAQ
Heating repair California — questions answered
Everything California customers ask before scheduling their heating repair.
Get your heating diagnosed and fixed today.
Video-documented diagnosis. Carbon monoxide safety assessed. Fix it or you don’t pay. Same-day available across all 5 California markets.
We fix the problem or you don’t pay — guaranteed on every repair.