RV Air Conditioning and Furnace Repair in Brea, CA
RV air conditioner repair in Brea, CA covers the whole climate system: rooftop and ducted cooling from Coleman Mach, Dometic Penguin and Brisk, Advent, and Furrion Chill, plus Suburban and Atwood forced air furnaces, heat pump equipped units, and hydronic systems including AquaHot and Oasis. We diagnose weak cooling, hard starting compressors, units that trip on a 30 amp pedestal, furnaces that light and immediately shut down, duct and plenum losses, and roof gasket leaks around the 14 by 14 inch opening. Work is done in shop with the coach on power and a full temperature split test at the end.
The line between this page and the electrical page runs at the breaker. If the unit has correct voltage at its own terminal block and still will not cool, it is ours. If the pedestal, the transfer switch, the panel, or the coach wiring cannot deliver voltage under load in the first place, that is an electrical diagnosis. Generators are separate again, even though the air conditioner is usually the load that exposes a weak generator.
- California BAR licensed ARD00288521
- 35,000 square feet facility
- All work performed in shop at our Yorba Linda facility
- Direct billing with 16 carriers on covered claims
Ready to get this looked at?
Electrical and systems faults get bench time, not guesswork. Diagnostic time is credited against the repair when you authorize the work.
What this repair covers
A rooftop air conditioner is a sealed system: compressor, condenser coil, evaporator coil, capillary or orifice metering, and a fan motor turning two blowers on one shaft. There is no service port on the vast majority of RV rooftop units, which means they are not recharged in the field. Diagnosis is therefore about proving whether the sealed system is intact and whether everything feeding it is doing its job.
Furnaces are a different animal, a sequence of safety interlocks that each have to be satisfied in order. Most furnace complaints are one interlock failing to close, not a dead furnace.
Scope for this page:
- In scope: rooftop cooling units, ducted and non ducted, including full unit replacement and upgrade.
- In scope: start and run capacitors, hard start and soft start module installation, fan motors, and control boards.
- In scope: thermostats, wall controls, thermistors, and multi zone control wiring.
- In scope: roof gasket replacement, mounting bolt torque, and leaks at the air conditioner opening.
- In scope: ducted plenum and ceiling duct leak correction, return air path repair, and register replacement.
- In scope: Suburban and Atwood furnaces, sail switches, limit switches, igniters, gas valves, and combustion blowers.
- In scope: heat pump reversing valves and low ambient lockout behavior.
- In scope: AquaHot and Oasis hydronic burners, zone pumps, coolant loops, and heat exchangers.
- Out of scope: chassis dash air conditioning on the engine side, generator faults, and shore power supply problems.
Damage and failure modes we see
Rooftop air conditioners live in the worst environment on the vehicle: full sun, constant vibration, and a mounting that has to seal a large hole in a flexible roof. Furnaces live in a sealed compartment with combustion air and a lot of dust. Both fail in predictable ways.
Capacitor failure and hard starting compressors
The start capacitor is the single most common failure on any RV rooftop unit. Heat degrades the dielectric, capacitance drifts below spec, and the compressor can no longer break away from a standstill. The symptom is a hum, a click, and a fan that runs while nothing gets cold, often with lights dimming across the coach at the moment of the attempt.
Running a compressor repeatedly against a weak capacitor draws locked rotor current for seconds at a time. That heats the motor windings well past their insulation rating, and a compressor that could have been saved by a capacitor becomes a compressor replacement, which on most units means a whole new rooftop unit. This is the failure where waiting a month genuinely changes the price.
Low voltage at the unit under load
An air conditioner asked to start on 103 volts draws far more current than one starting on 120. Long extension cords, undersized adapters, a 30 amp pedestal shared across a crowded park, corroded shore cord contacts, or a failing transfer switch all sag voltage exactly when the compressor needs it most.
Owners read the resulting failure as a bad air conditioner. We measure at the unit terminal block during a start attempt, not at an outlet after the fact. Chronic low voltage starting is a slow way to cook a compressor, and a soft start module reduces the inrush enough to make marginal supply survivable, which is why we install them so often on coaches running two rooftop units on 30 amps.
Roof gasket compression loss and water at the ceiling
The unit seals to the roof with a thick foam gasket compressed by four bolts through the 14 by 14 inch opening into the interior ceiling assembly. The foam takes a compression set over years and the plywood or aluminum framing around the opening can crush slightly. Owners then overtighten the bolts trying to stop a drip, which distorts the ceiling plenum and cracks it.
The symptom is water at a ceiling corner during rain or heavy washing, sometimes appearing feet away from the unit because it tracks along a ceiling rafter. Left alone this rots the roof decking around the opening, and now the repair includes structural decking work rather than a gasket.
Duct and plenum losses in ducted systems
In a ducted coach the air conditioner discharges into a plenum that feeds ceiling ducts running the length of the roof. Those ducts are often little more than channels formed between the roof structure and the ceiling panel, sealed with foil tape that lets go with heat cycling. Cold air then dumps into the roof cavity instead of the cabin.
The tell is a large temperature difference between the register nearest the unit and the one at the far end, or a unit that runs continuously and never satisfies the thermostat while measuring a perfectly good temperature split at the evaporator. Owners get told they need a bigger unit. They usually need their ducts sealed and their return air path corrected.
Furnace sail switch and limit switch lockouts
A Suburban NT series or an Atwood furnace has to satisfy a sequence: thermostat calls, combustion blower spins up, the sail switch closes to prove airflow, the board opens the gas valve, the igniter sparks, and the flame sensor proves flame. Dust loading on the blower wheel, a partially blocked return, or a closed register reduces airflow just enough that the sail switch stops closing.
The symptom is a furnace that blows air, clicks, and then goes cold, over and over. Owners often blame propane. A separate failure mode is the high limit switch cycling the burner off because the cabin air path is restricted, which short cycles the furnace, wears the gas valve, and eventually cracks the heat exchanger. A cracked heat exchanger is a combustion product intrusion risk and takes the furnace out of service permanently.
Heat pump limits and reversing valve faults
Heat pump equipped rooftop units move heat rather than making it, so they lose capacity as outdoor temperature falls and lock out entirely somewhere in the low forties Fahrenheit. Owners with a heat pump coach in a cold snap conclude the unit is broken when it is doing exactly what it is designed to do.
Genuine faults are a stuck reversing valve, which leaves the unit cooling when it should be heating, and a failed defrost or ambient sensor that locks the unit out at temperatures where it should still work. Both present as no heat, and telling them apart from normal lockout requires measuring coil temperatures rather than trusting the wall control.
Hydronic system faults on AquaHot and Oasis
Hydronic systems heat a glycol loop with a diesel burner and an electric element, then move that heat to zone exchangers and the domestic water coil. The most common failures are a fouled burner nozzle and electrode assembly, air locked in the loop after a coolant service, a failed zone circulating pump, and low coolant from a slow weep at a hose clamp.
Symptoms are zone specific: one bedroom that never warms points at a zone pump or an air lock, while a system that heats water but no zones points at the loop side. Running a hydronic system low on coolant overheats the burner chamber, and a burner chamber is not a cheap component.
How we perform this repair
Climate work is measurement work. Temperature split, amperage, static voltage under load, and airflow are numbers, and numbers are how we tell a tired unit from a bad install.
The standard sequence on a cooling or heating complaint:
- Measure supply voltage at the unit terminal block with a Fluke meter during a start attempt, and record the sag. Anything below roughly 105 volts at the moment of start changes the diagnosis before we touch the unit.
- Clamp the compressor and fan circuits with an ammeter and compare running amps and locked rotor draw against the data plate. This separates a weak capacitor from a shorted compressor winding without disassembly.
- Test capacitors under load with a capacitance meter rather than by appearance. A capacitor that is not visibly bulged can still be 30 percent low, which is enough to prevent a start on a hot day.
- Run a temperature split test: dry bulb at the return and at the nearest supply register after ten minutes of steady running. A healthy unit produces roughly an 18 to 22 degree Fahrenheit split. A low split with normal amps points at airflow, not refrigerant.
- On the roof, pull the shroud and inspect the condenser coil, the fan motor bearings, the blower wheel balance, and the gasket compression. Coils get cleaned with a foaming coil cleaner and a low pressure rinse, never a pressure washer, which folds fins flat.
- On furnaces, run the sequence with a manometer on the gas manifold to confirm pressure at the valve, verify sail and limit switch closure with a meter rather than a jumper, inspect the combustion wheel and the exhaust tube, and check the flame pattern at the sight port.
- Replace what testing condemned, then reseal. New rooftop installs get a fresh gasket, bolts torqued to the manufacturer sequence rather than to feel, and the ceiling plenum checked for cracks before the trim goes back.
- Finish with a full run test: cooling and heating cycles from the wall control, split measured again, amperage logged, and a water test around the roof opening on any unit that was lifted.
What this costs and how we quote it
Climate work is quoted after diagnostics, never before, because the same complaint of it will not cool covers a capacitor, a duct leak, a low voltage supply problem, and a failed compressor. Those four repairs are nothing alike in cost and only measurement tells them apart.
Diagnostic time is billed at our published rate and credited against the authorized repair. Rooftop replacement is quoted as a package: the unit, the ceiling assembly or plenum if the existing one is not compatible, gasket, hardware, thermostat compatibility, labor to lift and set, and sealing. Furnace work is quoted by component after the sequence has been tested. Hydronic work is quoted by subsystem, since a burner service and a zone pump replacement are different jobs. Our pricing page has the current rate structure and the credit policy.
Vehicles we perform this on
Roof structure decides everything about a rooftop unit. A fiberglass roofed Class A takes a different mounting approach than a membrane over plywood travel trailer, and a high cube van or box truck conversion often needs a reinforced curb built into the opening because the roof panel alone will not carry the load in a crosswind. Duct layout is equally platform specific.
What this page does not cover
- breakers, panels, transfer switches, and shore cords Supply problems upstream of the unit terminal block.
- generators that cannot carry an air conditioner Generation faults, not climate equipment faults.
- roof membrane, decking, and sealant work Roof structure around the opening rather than the unit in it.
Get a written scope before the damage spreads
Electrical and systems faults get bench time, not guesswork. Diagnostic time is credited against the repair when you authorize the work.
If this damage is on an insurance claim
The one climate failure that lands on a claim reliably is hail. A rooftop shroud and condenser coil take direct hits, fins flatten, the shroud cracks, and the unit loses capacity even though it still runs. Adjusters frequently write the shroud and miss the coil, and a bent coil is a real capacity loss that shows in a temperature split test.
Impact damage from a low clearance strike, tree limbs, or debris also qualifies. Age related capacitor and compressor failures do not. We photograph coil damage with a scale reference and include split test numbers in the documentation so the loss is quantified rather than argued. Our hail damage claims page covers how those supplements are handled.
Why Brea owners bring this work to us
Rooftop work needs roof access with fall protection, a way to lift a 90 pound unit safely, and a shore power supply that can actually deliver full amperage so a unit can be tested under real load. Driveways in Brea have none of that, which is why owners make the short drive to our facility on La Palma Ave in Yorba Linda instead.
We have operated here since 2015 under California Bureau of Automotive Repair license ARD00288521 with EPA identification CAL000367879, and we hold direct billing relationships with 16 major carriers for the hail and impact side of this work. Everything is done in shop. We do not run mobile service, roadside calls, or fleet route visits.
Frequently asked questions
Why does my RV air conditioner run but barely cool?
Weak cooling with the compressor running is usually airflow, not refrigerant. Check for a dirty evaporator filter, a blocked return air path, a crushed or leaking ceiling duct, and a condenser coil packed with cottonwood or road film. We confirm with a temperature split measurement: a healthy unit drops return air roughly 18 to 22 degrees Fahrenheit, and a good split with poor cabin cooling points squarely at duct losses.
Can an RV rooftop air conditioner be recharged with refrigerant?
Almost never. RV rooftop units are sealed systems built without service ports, and the manufacturers do not supply charge specifications or a service procedure for them. A unit that has genuinely lost charge has a leak in a sealed assembly, and the economical repair is unit replacement. Anyone offering to top off a rooftop RV unit is adding ports to a system that was not designed for them.
What does a soft start module actually do?
It ramps the compressor up instead of slamming it to full speed, which cuts starting inrush current by roughly half to two thirds. That lets two rooftop units coexist on a 30 amp service, lets a marginal generator carry an air conditioner, and reduces the voltage sag that shortens compressor life. It does not add cooling capacity and it will not fix a unit that is already failed.
My furnace blows air but never gets hot. What is wrong?
That pattern almost always means the ignition sequence is failing an interlock, most often the sail switch not proving airflow because the blower wheel is dust loaded or the return path is blocked. Other causes are a failed igniter, a gas valve not opening, low manifold pressure, or a flame sensor that cannot prove flame. Propane supply is the last thing to suspect if other appliances light normally.
Why does my heat pump stop heating when it gets cold outside?
That is normal behavior, not a fault. A heat pump moves heat from outdoor air, and as outdoor temperature falls there is less heat available, so capacity drops and the unit locks out somewhere in the low forties Fahrenheit. Below that point the propane furnace or an electric element is supposed to take over. A heat pump that fails to heat in mild weather is a genuine fault, usually the reversing valve.
Water drips from the ceiling near my air conditioner when it rains. Is the roof leaking?
Usually it is the air conditioner gasket rather than the roof membrane. The foam gasket between the unit base and the roof takes a compression set over the years and stops sealing at the 14 by 14 inch opening. The fix is a new gasket with the mounting bolts torqued to the manufacturer sequence. Overtightening to stop a drip crushes the ceiling plenum and makes it worse.
Can I upgrade from a 13,500 BTU unit to a 15,000 BTU unit?
Often yes, if the roof opening, the ceiling assembly, the wiring gauge, and the breaker all support it. The limits worth checking are the branch circuit ampacity, whether your thermostat and control board are compatible with the new unit, and whether your total electrical service can carry the extra load. On ducted coaches the plenum and duct sizing also matter, since a larger unit into undersized ducts gains you very little.
How often should rooftop units be serviced?
Once a year before the hot season, plus a gasket inspection at the same interval. Service means cleaning the condenser and evaporator coils, checking capacitor values under load, inspecting fan motor bearings and blower wheel balance, verifying gasket compression, and running a temperature split test. Coils in a coach stored under trees load up far faster than that and deserve a mid season check.
Written and reviewed by the OCRV Center Technical Team. Last updated .
Book your paid estimate
Electrical and systems faults get bench time, not guesswork. Diagnostic time is credited against the repair when you authorize the work.
Related repairs and pages
- shore power, panel, and transfer switch diagnosisWhere a low voltage supply problem gets solved.
- generator diagnosis and load testingThe air conditioner is usually what exposes a weak generator.
- roof decking and membrane repairNeeded when a leaking air conditioner opening has rotted the decking.
- hail damage to shrouds and coilsThe impact side of rooftop unit damage.
- diesel pusher climate systems
- fifth wheel ducted cooling
- Class C rooftop units
- high cube van roof mounting
- ambulance climate equipment
- documenting hail damage to rooftop equipmentCoil damage is a measurable capacity loss, not a cosmetic one.
- how diagnostics and replacement are quoted
- our shop and roof access equipment
- book climate system diagnostics