6 Questions About Howden Equipment I Wish I'd Asked Before My First Purchase

What I learned from a $3,200 mistake on my first Howden blower order

In my first year (2017), I made the classic rookie error: assumed 'standard' meant the same thing to every vendor.

I ordered a Howden roots blower for a wastewater aeration project. Specs looked fine. Price was competitive. Delivery was on time. Then we installed it.

The noise level was 8 dB above what the plant's permit allowed.

Not a typo. An actual spec mismatch I'd ignored because the datasheet said 'standard industrial blower.' Cost me $3,200 in acoustic enclosures plus a 2-week delay. And the embarrassment of explaining to the plant manager why his new equipment couldn't legally run at night.

Lesson learned: Always ask the specific question. Don't assume 'standard' covers your site's unique constraints.

Since then, I've made (and documented) 14 more significant mistakes—totaling roughly $17,000 in wasted budget. Now I maintain our team's pre-purchase checklist. Here are the questions I wish someone had handed me before I started.

1. How do I know if a Howden blower is the right choice for my application?

Short answer: depends on your pressure and flow requirements. Howden roots blowers (positive displacement) excel at low-pressure, high-volume applications—think aeration, pneumatic conveying, and biogas handling. Centrifugal blowers are better for lower flow at higher pressures.

But here's the nuance I missed: inlet conditions matter hugely. My mistake was specifying a blower based on standard conditions (14.7 psi, 60°F). The actual site had 95°F ambient air with siloxanes from the digester gas. The blower ran hot. Efficiency dropped. We had to add inlet cooling and a filtration skid—an extra $4,800.

Real talk: When in doubt, ask Howden's application engineers for a performance curve at your actual site conditions. That's not weakness—that's doing your homework.

2. What should I inspect before buying used Howden refrigeration equipment?

I've bought—and regretted—used refrigeration gear. Here's my current checklist:

Compressor hours: Howden screw compressors typically need major service around 40,000–60,000 hours. If a used unit has 35,000 hours, plan for a $6,000–$12,000 overhaul within two years.

Oil analysis: Request the last two oil samples. High iron or copper content indicates bearing or rotor wear. On a $15,000 used compressor, that's either a negotiating point or a walk-away signal.

Tube bundle condition: For used heat exchangers and evaporators, ask for borescope photos. Tube fouling in refrigeration systems is common—and expensive to clean. I once skipped this and discovered 40% of tubes were plugged. That cost $2,100 in chemical cleaning plus downtime.

Control system vintage: Older Howden units may have proprietary controllers that are no longer supported. Factor in a $3,000–$5,000 retrofit if you want modern integration.

To be fair, buying used can save 30–50% versus new. But only if you know what you're inheriting. I get why people chase the lower price—budgets are real. The hidden costs are what get you.

3. Can I use an infrared heater near my Howden refrigeration equipment?

Technically, yes. Should you? Probably not in the way you're thinking.

Infrared heaters work well for spot-heating areas in cold storage facilities—loading docks, service bays, operator stations. But they're not a substitute for proper ambient heating around refrigeration equipment.

Here's why: infrared heats objects, not air. That sounds efficient (and it is, for people). But your Howden compressor's condenser relies on ambient air temperature for heat rejection. If you're heating the compressor skid with infrared, you're making its job harder.

Best practice: use infrared for worker comfort zones only. Keep the equipment area at the design ambient temperature—usually 50–95°F for Howden refrigeration packages. A $400 infrared heater pointed at a $25,000 compressor to 'keep it warm' is a bad call. The compressor doesn't need warmth. It needs proper airflow.

Worse than expected outcome: I saw a facility where an infrared heater was aimed at the evaporator to prevent frost. Raised the suction temperature by 6°F. System capacity dropped 15%. Electricity bill went up 18% the following month. All because someone thought they were being helpful.

4. How do I choose the right oil pressure sensor for a Howden screw compressor?

Not all pressure sensors are created equal—especially in industrial refrigeration where oil carries refrigerant carryover. This matters because sensor failure can lead to nuisance shutdowns or—worse—lubrication loss.

What I've learned from replacing seven sensors in three years:

Media compatibility: The sensor's wetted parts need to handle the specific oil-refrigerant mixture in your system. Ammonia systems (common with Howden NH3 compressors) require stainless steel diaphragms—copper alloys will corrode. For HFC systems, most standard sensors work, but check the O-ring material for compatibility with POE oils.

Response time: For safety-critical monitoring (loss of oil pressure cutout), look for a response time under 5 milliseconds. Slower sensors can miss transient pressure drops during startup—leading to a $6,000 bearing replacement when the safety system didn't trip fast enough.

Signal type: 4–20 mA sensors are industry standard for a reason: they're less susceptible to noise than voltage-based sensors in industrial environments with VFDs. I learned this after chasing phantom pressure readings for two weeks—turned out the 0–10V sensor was picking up EMI from the compressor VFD.

Pro tip: Standardize on one sensor model across your Howden compressor fleet. The cost per sensor is typically $80–$200. The cost of a mixed fleet with incompatible spare parts is frustration and downtime.

5. How do I properly clean the ice maker connected to my Howden refrigeration system?

This question comes up more than I'd expect. The short version: ice maker cleaning is essential, but the method depends on your type.

For modular ice machines fed by Howden chiller systems—common in food processing—here's what works and what doesn't:

Mineral scale removal: Use an NSF-approved descaler (usually a phosphoric or citric acid solution). Run a cleaning cycle per manufacturer specs—typically 15–20 minutes with recirculation. Don't use vinegar or bleach; they can damage the evaporator plate and leave residues.

Frequency: Every 3 months for moderate water hardness (5–10 grains). Monthly if your water is harder. I had a client who skipped cleaning for 6 months—the ice production dropped 30% and the compressor suction pressure went up 4 psi because of the insulating scale layer. That's wasted energy and capacity.

The Howden connection: If your ice maker is part of a larger Howden refrigeration system, coordinate cleaning with the system maintenance schedule. Shutting down the ice maker for cleaning while the rest of the system is under partial load can cause liquid slugging if not managed carefully. Ask me how I know—$1,100 in compressor valve repairs from exactly that.

One more thing: After cleaning, always check the ice quality. If you see white dust or cloudiness, the rinse cycle was insufficient. That's a food safety risk, not just a quality issue.

6. When should I replace rather than repair an old Howden blower or compressor?

This is the question that separates experienced buyers from the rest. The answer isn't about which option is cheaper—it's about total cost of ownership and operational risk.

I created a decision framework after a painful experience in 2022. A Howden centrifugal compressor had recurring bearing failures—three in 18 months. Each repair cost $2,800–$4,500 plus 3–5 days of downtime. The plant manager kept approving repairs because 'replacement is $28,000.'

But he wasn't counting the production losses. Each downtime event cost approximately $1,200/hour in lost throughput. Three failures × 4 days × 8 hours × $1,200 = $115,200. Versus a $28,000 replacement. The math wasn't even close.

My rule of thumb now:

Repair if: The compressor has under 30,000 hours, the failure is a known wear item (seals, bearings, gaskets), and the downtime cost is under $500/hour.

Replace if: The unit has over 50,000 hours, you've had more than two major repairs in 3 years, or the control system is obsolete. The 'but we've always repaired it' mindset costs more than the invoice shows.

I get why people hesitate. A $28,000 capital expense is scary. A $4,500 repair that gets you running again feels safer. But you're not buying a repair—you're buying operational risk. A vendor who says 'we'll fix it again' without running this calculation isn't doing you a favor.

That's the lesson I keep coming back to: the right answer often isn't the comfortable one.