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60,000 CFM
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1,481 kW
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up to 30:1
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6–8 weeks
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Design airflow
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Burner input
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Turndown
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Lead time
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01 Project at a Glance
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Item
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Specification
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Equipment
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Industrial direct-fired make-up air unit (MUA), non-recirculating
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Airflow
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60,000 CFM design / 40,000 CFM minimum
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External static pressure
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0.50 in. w.c.
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Heating
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Direct-fired natural gas, fully modulating
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Burner input / output
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5,054,000 BTU/h (1,481 kW) / 4,650,000 BTU/h (1,363 kW)
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Temperature rise
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approx. 71.8 °F (discharge approx. 80.8 °F at 9 °F outdoor)
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Fan arrangement
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Twin 30" DWDI centrifugal blowers, 40 HP total, VFD driven
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Electrical supply
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460 V / 3-phase / 60 Hz
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Gas supply
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Natural gas, approx. 1,020 BTU/ft³, 1–5 psi
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Gas consumption
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approx. 4,955 CFH at full fire
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Controls
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PLC + HMI, Modbus RTU / RS-485, 0–10 V
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Installation
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Outdoor rooftop, horizontal, down-discharge
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Project location
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Toronto, Ontario, Canada — sea level
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Client
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Established HVAC engineering and design-build company, Ontario, Canada
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02 The Client
The enquiry came from a well-established Canadian HVAC engineering and design-build company based in Cambridge, Ontario, founded in 1980 and representing more than 40 manufacturers across southwestern Ontario. With warehouses in Cambridge, Hamilton and London and an in-house team of engineers and technicians, the client delivers ventilation and indoor air quality solutions and runs its own design-build projects.
This was not a standard product enquiry. The client is a technical buyer: the enquiry arrived with a full technical specification, a reference drawing from a North American manufacturer, and an explicit instruction — do not copy the reference design, propose an equivalent or improved engineered solution instead.
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What this tells us
The client evaluates engineering capability, not just price. Every figure in our proposal would be checked by a qualified engineer before it reached a purchase decision.
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03 The Challenge
Four issues had to be resolved before any credible proposal could be issued.
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#
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Challenge
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Why it mattered
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1
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Not our standard product category
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A 60,000 CFM direct-fired MUA sits in industrial combustion and air-handling territory, beyond a standard spray booth. The burner, gas train and flame safeguard had to be engineered from scratch, not lifted from an existing model.
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2
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North American certification
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In Canada, a non-recirculating direct-fired industrial air heater must be listed to ANSI Z83.4 / CSA 3.7. CE marking is not accepted. Without a clear certification route, the unit could not legally be installed.
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3
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The specified figures did not add up
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Airflow, temperature rise and heating output as given could not all be true at the same time. Proceeding without resolving this would have produced a unit that missed its duty.
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4
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Matching plant that already exists
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The unit had to be balanced against existing exhaust, fit a roof structure, connect to existing gas and electrical services, and talk to the building management system.
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04 Engineering Analysis — Catching the Inconsistency
Before selecting any component, we reconciled the client's three headline figures against the standard-air sensible heat relationship, Q = 1.08 × CFM × ΔT, where 1.08 is derived from air density 0.075 lb/ft³, specific heat 0.24 BTU/lb·°F and 60 minutes.
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Check
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Result
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Output required to lift 60,000 CFM by 77 °F
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4,989,600 BTU/h
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Output specified by the client
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4,649,938 BTU/h
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Shortfall
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339,662 BTU/h (approximately 6.8%)
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Practical consequence
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At 4.65 MMBTU/h the unit can lift 60,000 CFM by only about 71.8 °F, or can lift 77 °F across only about 55,900 CFM
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Our approach
Rather than quietly oversizing the burner or silently accepting a lower duty, we put the contradiction on the table and asked the client to choose. They confirmed Option A: airflow is the priority, a slightly lower temperature rise is acceptable. That single answer fixed the burner size, the gas pipe sizing and the price — and removed a dispute before it existed.
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Matching new equipment to plant that already exists is often harder than the equipment itself
05 The Engineered Solution
5.1 Burner — Eclipse AH-MA line-type burner, 1,481 kW
We selected the Eclipse AH-MA (Honeywell Thermal Solutions), a modular raw-gas direct-fired line burner purpose-built for fresh-air make-up and process air heating. Its modular straight, tee and cross sections let us build a burner array that suits the duct cross-section rather than forcing the duct to suit the burner.
Eclipse AH-MA class line-type burner — direct-fired, modular, uniform flame
আপনার বার্তাটি 20-3,000 টির মধ্যে হতে হবে!
