If you’ve ever walked past a food processing plant on a crisp morning and noticed that it’s not spewing a massive cloud of steam into the sky, or a warehouse that keeps its loading docks at a steady, comfortable temperature year-round, you’ve probably encountered a well-maintained Thermal Energy Recovery System (TERS). At our company, we’ve spent over a decade designing, installing, and servicing these systems, and one thing we’ve learned is that a TERS isn’t a “set it and forget it” piece of equipment. Too often, we see clients cut corners on maintenance, only to face costly breakdowns, lost energy efficiency, or even unplanned downtime that derails their entire operation. Today, I want to share the actionable, science-backed maintenance steps our in-house service team recommends to keep your TERS running at peak performance—because we’ve seen firsthand how proper care translates to real, bottom-line savings for businesses across manufacturing, commercial HVAC, wastewater treatment, and even food and beverage production. Thermal Energy Recovery System
First, let’s ground this in why maintenance matters more for TERS than for many other industrial systems. Unlike a standard HVAC unit that just heats or cools air, a TERS captures waste thermal energy from exhaust streams—think hot air from a factory oven, warm water from a processing line, or even moist air from a commercial laundry—and transfers that heat to incoming fresh air, process water, or other streams that need conditioning. The core of this system is the heat exchanger, which is the workhorse that makes the entire energy recovery process possible. Over time, that heat exchanger can get fouled with debris, scale, or biological growth, which acts as an insulating layer and kills efficiency. For context, a heat exchanger with just a 0.1mm layer of scale can reduce heat transfer by up to 10%—not a huge number on paper, but for a system that processes 100,000 CFM of exhaust air, that’s enough to waste tens of thousands of dollars in energy every month. So the first, and most critical, maintenance task is regular heat exchanger inspection and cleaning, tailored to the type of TERS you have.
Let’s break down TERS into two of the most common types our clients use: air-to-air (for commercial HVAC and manufacturing exhaust) and liquid-to-liquid (for wastewater and process water applications). For air-to-air systems, fouling usually comes in the form of dust, lint, pollen, or food particles—all things that build up on the heat exchanger’s metal fins. Our team recommends inspecting air-to-air heat exchangers every three months for light-duty applications (like office building ventilation) and every one to two months for heavy-duty industrial use (like metal stamping or grain processing). When you inspect, use a flashlight and a borescope to get between the fins—fin spacing is often as small as 1mm, so it’s easy to miss buildup. We never recommend using high-pressure water to clean air-to-air heat exchangers, because that can bend the thin fins and create gaps that reduce efficiency. Instead, for light fouling, use a soft-bristled brush or a low-pressure (under 50 PSI) air blow-off. For heavier buildup, use a pH-neutral, industrial-grade heat exchanger cleaner that’s designed not to corrode aluminum or stainless steel fins—we’ve found that many generic cleaners etch metal over time, so it’s worth spending a few extra dollars on a product tested for your specific heat exchanger material.
For liquid-to-liquid TERS, the biggest enemy is scaling and biological fouling. If your system is capturing heat from hot process water, minerals like calcium carbonate and magnesium bicarbonate can precipitate out of the water as it cools, forming a hard, crusty scale on the heat exchanger tubes. For example, a wastewater treatment plant client of ours saw their TERS efficiency drop by 22% in just 18 months because of scale buildup. To prevent this, first, monitor water quality at least twice a month—test for pH, total dissolved solids (TDS), and hardness levels. If hardness exceeds 200 ppm, you’ll need a water softener or a chemical dosing system to treat the water before it enters the TERS. We also recommend scheduled flushing: for liquid-to-liquid systems operating at over 120°F, flush the heat exchanger with low-pressure, warm water every six months to remove loose scale and sediment. If scale is already present, use a descaling agent made for your metal type—citric acid works well for stainless steel, while phosphoric acid is effective for carbon steel, but always test a small, hidden section first to avoid corrosion.
Next, don’t overlook the ancillary components that keep your TERS running smoothly. The heat exchanger is the star, but the fans, pumps, filters, and controls are the supporting cast, and a single faulty fan motor can bring the entire system to a halt. For air-to-air TERS, inspect supply and exhaust fans monthly. Check for abnormal vibration, which is a sign of unbalanced blades or worn bearings. We recommend lubricating fan bearings every six months with a high-temperature, industrial-grade grease—never use household grease, which breaks down at the high temperatures many TERS operate in. Also, replace the system’s air filters every one to three months, depending on your environment. Clogged filters force fans to work harder, increasing energy use by up to 15%, and can even cause air to bypass the heat exchanger entirely, reducing energy recovery.
For liquid-to-liquid systems, pump maintenance is key. Inspect pump seals monthly for leaks—even a small drip over time can introduce air into the system, which reduces heat transfer and causes cavitation (bubbles that damage pump impellers). Every year, disassemble and inspect pump impellers for corrosion or buildup, and replace seals every two years as a standard preventive measure. Another often-overlooked component is the bypass damper, which is designed to let exhaust air or water bypass the heat exchanger during startup or low-load periods. Test these dampers quarterly to make sure they open and close fully—stuck dampers can force the system to work harder to maintain temperature, wasting energy.
Beyond physical components, monitoring TERS performance with real-time data is one of the most effective maintenance steps our service team offers. Every TERS should have a built-in system that tracks inlet and outlet temperatures of both streams, air flow rates, and energy recovery efficiency. If you notice that the temperature difference between the incoming and outgoing streams is dropping by more than 5% over a month, that’s a clear sign that the heat exchanger is fouled, even if you can’t see debris during an inspection. We recommend setting up automated alerts for your team—text or email notifications if temperature delta drops below a preset level, or if fan power use spikes. For larger operations, our team can connect your TERS to our remote monitoring platform, where we track performance 24/7 and flag issues before they become costly problems. Last year, we had a manufacturing client that caught a clogged heat exchanger coil through our remote monitoring, fixed it during a planned weekend shutdown, and avoided $12,000 in lost production time.
Seasonal maintenance is another critical piece that many businesses miss. TERS needs to be adjusted for different operating conditions throughout the year. In the winter, when the goal is to maximize heat recovery to keep incoming air warm, you’ll want to ensure the bypass damper is closed during normal operation and that the heat exchanger is clean. In the summer, when you might be using the TERS to capture cool exhaust air to condition incoming fresh air, you’ll need to check for moisture buildup in the heat exchanger, which can cause mold or bacterial growth. Our team recommends a full pre-season inspection before winter and summer—checking insulation on piping, calibrating temperature sensors, and testing all safety features, like pressure relief valves for liquid systems. For example, a food processing client in the Midwest had a mold outbreak in their TERS during a humid summer because they didn’t dry the heat exchanger after flushing, leading to a temporary shutdown and a fine from the local health department. That’s a avoidable cost that comes from skipping seasonal maintenance.
Now, let’s talk about common mistakes that even experienced TERS users make. The first is using generic replacement parts instead of OEM (original equipment manufacturer) parts. We’ve seen clients buy cheaper fan belts or filters from a local hardware store, only to have the belt snap after three months or the filter cause increased air resistance, leading to higher energy bills. OEM parts are designed specifically for your TERS model, so they fit better and last longer. The second mistake is putting off maintenance during periods of low operation, like holidays or summer lulls. It’s tempting to skip cleaning or inspections when production is slow, but that’s exactly when small issues can turn into big ones. A few hours of maintenance during a holiday weekend is way cheaper than a 3-day shutdown when production ramps back up. The third mistake is skipping professional annual servicing. While regular in-house checks are important, a trained TERS technician can spot issues that in-house teams might miss—like internal corrosion on a heat exchanger, or misaligned sensors that skew performance data. Our team includes annual service contracts for all our installed systems, and we’ve found that clients with these contracts have 30% fewer unplanned downtime events than those who handle maintenance on their own.
I want to be clear: TERS is an investment in energy efficiency, and proper maintenance is how you protect that investment. We’ve seen systems that are 10 years old and still operating at over 90% efficiency because of consistent, proactive maintenance, and we’ve seen systems that fail prematurely because of neglected upkeep. The key is to make maintenance a scheduled, documented process, not a reactive chore. Keep a log of every inspection, cleaning, and part replacement—this not only helps you track performance over time but also ensures compliance with any industry regulations, like those for food and beverage or wastewater treatment.
If you’re looking to optimize your existing TERS, or you’re in the market for a new system and want expert advice on maintenance best practices, our team is here to help. We work with businesses of all sizes, from small manufacturing shops to large commercial facilities, to design, install, and service TERS that meet your specific needs. We don’t just sell equipment—we partner with our clients to ensure their thermal energy systems run as efficiently as possible for years to come. To learn more about our maintenance programs or to discuss your current TERS needs, we encourage you to reach out to our team for a no-obligation consultation.
Control Valve References:
- ASHRAE Handbook: Heating, Ventilating, and Air-Conditioning Systems and Equipment. American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2021.
- Industrial Heat Exchanger Maintenance Best Practices. American Industrial Hygiene Association, 2022.
- Energy Conservation in Industrial Thermal Systems. U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, 2020.
- Fouling Mitigation in Heat Exchangers: A Practical Guide. International Energy Agency, 2019.
- Remote Monitoring for Industrial HVAC Systems: Performance and Cost Savings. Applied Thermal Engineering, Vol. 181, 2020.
Hangzhou Meiya Power Generating Equipments Co., Ltd
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