The call that started it
September 2022. I was standing in a welding shop near Red Deer, Alberta, looking at a diesel heater that had probably been there since the late '90s. The customer, Dave, wanted it gone. He'd also just bought a Nest thermostat and assumed I could hook it up to whatever we installed. I thought that would be the easy part. It wasn't.
I handle service and logistics for an Alberta Hitachi HVAC dealer. I've been ordering parts and coordinating installs for eight years, and I've made enough preventable mistakes to fill a binder. In my first year, 2017, I ordered the wrong voltage fan coils on a $3,800 order and had to eat the return shipping. That one hurt. So I know what happens when you assume instead of verify. This 2022 job was a reminder of the same lesson.
The water heater vs boiler trap
Dave runs a small steel fabrication shop. The diesel heater in the corner was loud, smelled like fuel, and made the air feel greasy. Diesel prices had spiked, and he wanted something cleaner and cheaper to run. He said, "My buddy down the road used a $300 water heater to heat his whole shop. Why do you keep saying I need a boiler?"
That's when I almost went down a bad path. For two weeks I went back and forth on the water heater vs boiler thing. The water heater approach was basically cheaper on paper. A boiler was more expensive up front, but it was designed for closed-loop heating. The shop's overhead door opens constantly, so the system has to heat the space back up fast. A standard water heater tank is not built for that kind of duty cycle.
A water heater is built to make domestic hot water. A boiler is built to heat spaces. There are some water heaters rated for space heating, but if the model and installation aren't rated for it, you're not saving money—you're buying a future emergency.
I recommended the boiler. Dave still didn't love the price, but he said, "Okay, if it's the right way to do it, let's do it." That was the right decision. But the next mistake was waiting around the corner.
The Hitachi EC12 compressor parts detour
While I was waiting for the boiler quote to come together, another customer's chiller died. The data plate on the compressor was faded, but I could see it was a Hitachi unit. I searched online for "hitachi ec12 compressor parts" and found a listing that looked perfect. Same size. Same port locations. The price was reasonable, and the supplier could get it to us overnight.
I assumed the part number matched the compressor on the equipment. Didn't verify. When the parts arrived, the mounting flange was off by half an inch and the suction threads were different. $450 in parts, $120 overnight shipping, and three phone calls later, I realized the EC12 family has multiple variants, and the faded data plate had a suffix I hadn't noticed.
That mistake cost us a week of downtime and $570 in wasted money. It was also embarrassing because the customer is a long-time account. What made it worse is that I knew better. I have a checklist for part verification, but I skipped two steps because I was in a hurry.
The thermostat assumption
Back at Dave's shop, install day started well. We mounted the new condensing boiler, hung two hydronic unit heaters, and ran the PEX lines. Then Dave said, "So you're wiring up my Nest, right?"
I had not checked that. I assumed a Nest thermostat would work with a hydronic boiler because, you know, it's a thermostat. Not quite. Nest is designed mainly for forced air and heat pump systems. With a boiler, you often need a compatibility kit or an adapter, and some boiler controls don't work with it at all.
We ordered the adapter, made a second trip, and got it working. Dave wasn't angry, but he was right to be annoyed. If I had asked the thermostat question at the beginning, the first install visit would have gone smoother.
What I'd do differently
The final system works well. The diesel heater is gone. Dave's shop heats up faster, the air is cleaner, and his heating costs are lower than the previous winter. But the process had more friction than it should have.
So, for anyone dealing with an Alberta Hitachi HVAC system, or trying to replace a diesel heater, or stuck on the water heater vs boiler question, here's my list:
- Verify the full model number before ordering compressor parts. If you can't read it, call the supplier and get dimensions. Don't trust a search result.
- Ask about thermostat compatibility in the first conversation, especially if the customer bought their own Nest thermostat. It can save you a second trip.
- Treat water heater vs boiler as an engineering question, not just a budget question. A cheap solution that works at someone else's shop doesn't mean it'll work in your building.
- Use your checklists even when you're in a hurry. The skipped steps are the ones that cost $570.
Bottom line? Efficiency is competitive, but it starts before the equipment is unboxed. It starts with checking assumptions, confirming part numbers, and asking the boring questions early. I've caught 47 potential errors using these checklists in the last 18 months, and every one of those was cheaper than ignoring them.
If you're in Alberta and looking at a Hitachi HVAC system, or standing next to an old diesel heater wondering what to do next, ask the uncomfortable questions first. It's a lot cheaper than learning the hard way.
