HVAC Knowledge Base

The most common reasons a furnace stops working in Maine: (1) tripped circuit breaker — check the electrical panel; (2) clogged air filter starving the system of airflow — causing the high-limit switch to trip; (3) failed igniter — the furnace tries to start but can't light; (4) faulty flame sensor — the burner lights but shuts off after a few seconds; (5) the thermostat is set incorrectly or has a dead battery. Start with the filter and thermostat. If those are fine, call RG Mechanical at (207) 441-5820.

Check the thermostat mode and an accessible filter according to the owner's manual. Poor cooling can involve airflow, ice, refrigerant, controls, or electrical faults. If ice, leakage, unusual noise, or repeated shutdown occurs, stop cooling and arrange qualified service. Do not open electrical panels, repeatedly reset breakers, or handle refrigerant.

Common causes: the mode is set to 'Cool' or 'Fan Only' instead of 'Heat' (check the remote or wall controller), the outdoor unit is buried in snow or ice and needs to be cleared, the air filter inside is clogged, the refrigerant charge is low, or the defrost board has failed (preventing the unit from clearing ice). If clearing snow and checking the mode setting doesn't help, call us — the fix usually requires a technician.

Different sounds point to different problems: banging or popping at startup is usually ductwork expansion, but loud banging inside the unit suggests a cracked heat exchanger or failing blower wheel. Squealing or screeching indicates a worn blower motor belt or bearings. Rattling means a loose panel, screw, or debris. Rumbling from a boiler is scale buildup on the heat exchanger. Any loud or sudden new noise warrants a service call — especially banging or screeching, which indicate mechanical stress.

Brief changes in delivered-air temperature can occur during startup or defrost. Persistent cold air may involve settings, airflow, controls, refrigerant, or a reversing-valve fault. Check the operating mode and accessible filter using the owner's manual; persistent loss of heat needs qualified diagnosis, not a refrigerant top-up or repeated reset.

If there is a gas odor, smoke, a carbon-monoxide alarm, or symptoms of exposure, leave immediately and call emergency services from outside. Otherwise check thermostat settings and batteries using the owner's manual, then call to confirm service availability. Do not reset a burner lockout or repeatedly reset a breaker. Never use an oven or outdoor heater indoors; if using a portable electric heater, follow its instructions, keep it away from combustibles, plug it directly into a wall outlet, and do not leave it unattended.

Banging and rumbling from a boiler — called 'kettling' — is almost always caused by scale (mineral deposits) built up on the heat exchanger. Water trapped in the scale layer superheats and flashes to steam, creating the sound. Mild kettling can be treated with a descaling flush. Severe or persistent kettling may indicate heat exchanger damage that warrants replacement. Don't ignore it — a damaged heat exchanger can crack and create a CO hazard.

An odor can have several causes and cannot be diagnosed safely by duration alone. Stop using equipment with an unexplained burning, electrical, fuel, or persistent unusual odor and arrange qualified inspection. For smoke, a gas odor, a carbon-monoxide alarm, or exposure symptoms, leave immediately and call emergency services from outside.

Ice may involve restricted airflow, refrigerant, controls, or other equipment faults. Stop cooling, follow the manufacturer's instructions, and check only accessible filters or vents. Do not chip ice, apply heat, open electrical panels, or assume a thaw fixes the cause. Recurring ice needs qualified diagnosis.

Light outdoor frost may be normal during heating, but heavy ice that does not clear can involve airflow, drainage, sensors, controls, refrigerant, or a defrost fault. Defrost timing varies by model and conditions. Follow the owner's manual and request qualified service; do not chip ice, apply hot water, or bypass safety controls.

Possible causes include a blocked or damaged condensate drain, a pump fault, insulation problems, or an iced coil. Stop operating a leaking unit and protect the surrounding area without touching wet electrical components. Have the drainage and equipment inspected. Do not pour bleach or other chemicals into the unit unless the exact manufacturer procedure requires them.

Popping and rumbling can indicate sediment buildup. A qualified diagnosis should consider tank condition and manufacturer flushing guidance; compare repair and replacement estimates if damage is suspected.

Twice a year is the gold standard — heating systems in the fall (before the season starts) and cooling systems in the spring (before the heat hits). Heat pumps handle both heating and cooling, so they should be serviced twice a year as well. If you can only do one, prioritize fall service for heating safety before Maine winters set in.

Service life varies by exact model, installation, maintenance, operating conditions, water quality where relevant, and parts availability. Check the equipment label and current manufacturer guidance, then evaluate present condition and repair history.

Common causes in order of likelihood: clogged or dirty air filter, dirty evaporator or condenser coils, low refrigerant (heat pump or AC), failing capacitor causing the system to work harder, aging system that's lost efficiency, duct leaks, or poorly insulated pipes or ducts in unconditioned spaces. Start with the filter — it's free to check and often the culprit.

Bigger is not better with HVAC. An oversized system short-cycles — it turns on and off too frequently, which causes humidity problems, excessive wear, and higher energy bills. Proper sizing requires a Manual J load calculation that accounts for square footage, ceiling height, insulation, windows, air sealing, and climate zone. We perform this as part of every installation estimate.

Do not rely on a fixed percentage or age rule. Compare safety, condition, repair history, parts availability, exact-model performance, and written repair and replacement estimates.

We work with several top-tier manufacturers and recommend the best fit based on your home, budget, and goals. We don't push one brand — we push quality. We'll explain the tradeoffs between the systems we're recommending so you can make an informed decision.

Ask about the proposed scope, equipment, permits, scheduling, and documentation relevant to your project. Confirm any regulated credentials or insurance directly before work begins.

Call (207) 441-5820 to discuss the problem and current availability. Scheduling depends on existing commitments, weather, parts, travel, and the service needed.

Yes. Request an estimate for an installation or replacement. Repair visits may require diagnostic work; ask about current service and diagnostic charges when scheduling.

We serve Augusta and the surrounding Central Maine region. Contact us to confirm service in your specific town — our coverage area continues to grow.

A proper tune-up isn't just a visual check. For furnaces: we inspect and test the heat exchanger, igniter, burner, gas valve, blower motor, and flue. For boilers: burner inspection, heat exchanger check, pressure testing, water quality review, and safety valve test. For heat pumps and AC: refrigerant level check, coil cleaning, capacitor and contactor test, and airflow measurement. We document everything.

1-inch filters: every 1–3 months depending on household dust, pets, and occupancy. 4-inch media filters: every 6–12 months. HEPA filters: per manufacturer recommendation, typically every 12 months. A clogged filter is the single most common cause of HVAC problems — it starves the system of airflow and causes overheating, frozen coils, and premature failure.

This is the most common mistake homeowners make. HVAC systems can appear to be running fine while quietly degrading. Refrigerant leaks slowly over years. Heat exchangers develop hairline cracks. Capacitors weaken before they fail. By the time you notice a problem, significant damage is often already done. Annual service catches these issues at their cheapest point.

The heat exchanger separates combustion gases from household air. A suspected crack is a carbon-monoxide safety issue: stop using the equipment and follow emergency guidance. Inspection needs depend on equipment condition and manufacturer instructions, not age alone.

Dust and debris can accumulate on evaporator coils, blower wheels, and drain pans, affecting airflow and operation. Follow the equipment manufacturer's inspection and cleaning guidance and address confirmed moisture or biological-growth concerns appropriately.

An anode rod is a metal rod inside many tank water heaters that helps protect the tank from corrosion. Inspection and replacement timing varies by model, water quality, and manufacturer instructions.

Mini-split indoor units can accumulate dust and debris on filters, coils, drain components, and blower wheels. Follow exact-model manufacturer cleaning instructions and seek service for persistent odor, drainage, airflow, or inaccessible internal buildup.

A combustion analysis uses instruments to measure the efficiency and safety of your heating system's burner — checking flue gas temperature, CO levels, excess air, and efficiency percentage. It's the most accurate way to verify a furnace or boiler is burning fuel safely and efficiently. We include it in our annual heating system tune-ups.

A heat pump moves heat between indoors and outdoors and may use ducts or ductless indoor units. A mini-split describes a split system with compact indoor units; many provide both heating and cooling, while some models are cooling-only. Check the exact model rather than assuming all mini-splits have the same capabilities.

Low-temperature capacity varies by exact indoor and outdoor model combination. Compare current manufacturer capacity tables at the project's design temperature with a load calculation, and include backup heat where the design requires it.

AFUE measures fuel converted to useful heat, while heat-pump COP measures heat delivered relative to electricity consumed. These educational ratings are not directly interchangeable savings guarantees; verify exact-model data at relevant temperatures and compare current energy rates and usage.

Qualifying cold-climate heat pump projects may be eligible for Efficiency Maine incentives. Eligibility, amounts, paperwork, and processing change, so visit our rebates page and verify current requirements with Efficiency Maine before making a decision.

Each indoor air handler (head) serves one zone. For most homes, we see 1 head per floor working well for open-concept layouts, or 1 per room for more targeted comfort control. We assess your home's layout, insulation, and sun exposure to recommend the right number. Over-zoning adds cost; under-zoning leaves cold spots.

Timing depends on the number of indoor units, line-set routing, access, electrical work, permitting, equipment availability, site conditions, and commissioning. Ask for a project-specific schedule with the installation scope rather than relying on a generic hourly estimate.

A heat pump may operate alongside an existing boiler when the load calculation, controls, electrical capacity, and backup strategy support that design. Do not assume routine boiler use qualifies for an incentive: Efficiency Maine's current primary-heating heat-pump program requires existing boilers or furnaces to be reserved for emergency backup. Verify the exact program before choosing a design.

Most common causes: the indoor filter is clogged (check and clean it), the system is in 'heat' mode rather than 'cool' mode, low refrigerant from a slow leak, or a dirty evaporator coil reducing heat transfer. If cleaning the filter and checking the mode setting doesn't resolve it, call us — low refrigerant requires a licensed technician to diagnose and correct.

During heating mode in cold weather, the outdoor unit goes through a normal defrost cycle — brief frost is normal. Sustained ice buildup on the outdoor unit indicates a problem: low refrigerant, a faulty defrost board, poor airflow due to debris around the unit, or a refrigerant restriction. Ice on the indoor unit in cooling mode typically means a clogged filter or very low refrigerant. Either scenario needs professional attention.

A furnace heats air and distributes it through ductwork, while a boiler heats water for radiators, baseboards, or radiant tubing. Service life for either varies by model, installation, maintenance, conditions, and parts availability.

Repeated repairs, unexplained energy-use changes, banging or rumbling, corrosion, leakage, pressure problems, and limited parts availability can justify a replacement comparison. Diagnosis and written estimates help establish the appropriate next step.

Kettling is the banging or rumbling sound a boiler makes when scale (mineral deposits) builds up on the heat exchanger. Water trapped in the scale layer superheats and flashes to steam, causing the sound. Mild kettling can be addressed with a system flush and descaling treatment. Severe cases indicate heat exchanger damage and may require boiler replacement.

A brief burning smell at the start of the heating season — lasting 20–30 minutes — is normal. It's dust burning off the heat exchanger after sitting all summer. If the smell persists, smells like burning plastic or rubber, or occurs throughout the season, shut the system off and call us. Persistent smells can indicate overheating, a failing blower motor, or wiring problems.

A cracked heat exchanger is a serious safety issue. Do not run the furnace; follow carbon-monoxide emergency guidance and obtain qualified diagnosis plus written repair and replacement options.

AFUE is an educational rating describing how much fuel energy becomes useful heat. Condensing furnaces use a secondary heat exchanger and different venting. Verify the exact proposed model, venting requirements, and current manufacturer data; AFUE alone does not guarantee savings or payback.

Converting from oil is increasingly popular as natural gas is not available everywhere in Maine, but heat pumps are. If you have natural gas available, a high-efficiency gas furnace is a strong option. If not, a cold-climate heat pump with the existing oil system as backup is a great hybrid approach. We assess your specific situation and fuel options during our estimate.

The pressure relief valve (PRV) is a safety device that automatically releases pressure if the boiler exceeds safe operating limits. A PRV that drips or discharges regularly indicates the system pressure is too high — typically a waterlogged expansion tank or a filling valve issue. Never cap or plug a PRV — it's your last line of defense against boiler failure. If yours is discharging, call us.

Indicators include repeated refrigerant leaks, recurring repairs, limited parts or refrigerant availability, severe condition issues, or inability to maintain comfort despite correct sizing and operation. Compare diagnosis and written repair and replacement estimates.

R-22 is an ozone-depleting refrigerant whose US production and import ended under federal phaseout rules. For equipment using R-22, compare current refrigerant availability, leak diagnosis, condition, repair scope, and replacement estimates rather than assuming one financial outcome.

The two most common causes are: (1) restricted airflow from a clogged filter, closed vents, or dirty coil — without adequate airflow, the evaporator coil drops below freezing and ice forms; (2) low refrigerant from a leak. Turn the system to fan-only mode to thaw it, then check and replace the filter. If it refreezes, call us — low refrigerant needs professional diagnosis.

Most likely causes: low refrigerant from a leak, dirty condenser coil (the outdoor unit can't reject heat if it's clogged with dirt), failed capacitor (system runs but compressor isn't engaging), restricted airflow from a dirty filter, or a system that's simply undersized for the home. Start with the filter, then call for a diagnostic if the issue persists.

Once a year in spring, before the cooling season begins. The service includes coil cleaning, refrigerant level check, capacitor and contactor test, condensate drain flush, and airflow measurement. A clean, properly charged system uses significantly less electricity and is far less likely to fail on the hottest day of the year.

SEER2 is an educational seasonal cooling-efficiency rating. Verify current federal requirements and exact-model ratings through official and manufacturer sources, then compare design conditions, usage, and project cost without assuming a payback period.

Warning signs include rusty or discolored water, unusual odor, rumbling or popping, leakage, reduced hot-water delivery, repeated repairs, corrosion, or unavailable parts. Evaluate condition and manufacturer guidance rather than age alone.

Tankless units heat water on demand within rated capacity, while tank units store heated water. Compare demand, fuel or electrical capacity, venting, water quality, maintenance, exact-model data, installation scope, and a project-specific estimate.

An odor confined to hot water can involve water chemistry, bacteria, or an anode-rod reaction; it does not prove the rod has failed. Have the water supply and heater assessed before treatment. If a rotten-egg odor is present in the room rather than only the water, treat it as a possible fuel-gas leak: leave and call the gas supplier or emergency services from outside.

Hard water can cause limescale inside a tankless heat exchanger. Descaling method and frequency depend on water quality and the exact manufacturer's instructions; use only approved procedures and materials.

Rumbling or popping can indicate sediment buildup. Diagnosis should consider tank condition, leakage, water quality, manufacturer flushing guidance, and written repair or replacement estimates rather than age alone.

Yes, but there are considerations. Tankless water heaters require higher gas flow rates (if gas) or significant electrical capacity (if electric). We'll assess your existing gas line size and electrical panel. In some cases, the gas line or electrical service needs upgrading — we factor this into our estimates so there are no surprises.

Qualifying HVAC projects may be eligible for state or federal incentives. Eligibility, amounts, and tax treatment change; visit our rebates page and confirm current program and tax details with official sources before relying on them.

Results depend on the home, existing system, exact equipment, design, weather, use, and current energy rates. Compare recent energy history with a load-based design and project-specific operating-cost analysis; savings are not guaranteed.

HSPF2 is an educational seasonal heating-efficiency rating. Verify current program requirements and exact-model ratings through official and manufacturer sources. It does not by itself establish operating savings or service life.

Even an efficient HVAC system can struggle in a poorly insulated or air-sealed home because it must run longer. Before upgrading a system, consider whether insulation, windows, or air sealing are limiting comfort; an energy assessment can help prioritize improvements.

Smart thermostats can provide scheduling, remote control, and geofencing where compatible. Cost, energy impact, and incentive eligibility vary; verify equipment compatibility, current official program details, and project-specific pricing.