Alright, so you’ve got an old Dimplex heater mounted on the wall, or maybe you found one in storage. Your facilities person is on leave, your boss is asking if the conference room will be warm by tomorrow, and the unit just stares back at you with a bunch of knobs you don’t recognize.
I’ve been there. I’m the office administrator who inherited a dozen different heater models when we took over a new building in 2022. Sorting out how to actually operate them (and keep everyone from burning their hands or tripping a breaker) became a project. This checklist is for that exact moment.
Here are the 4 steps I follow when I run across an unfamiliar Dimplex heater or chiller unit.
Step 1: Identify the exact model — don't guess
This is the step almost everyone skips. Even if the thing says “Dimplex” on the front, there are about 15 different product categories under that name: convection heaters, radiant panels, oil-filled radiators, fan-forced heaters, baseboard units, storage heaters... and don't even get me started on the industrial chillers.
The controls are completely different for each type. A timer dial on an oil-filled radiator works nothing like the thermostat on a fan heater. I learned that the hard way when I cranked a storage heater expecting instant heat. Nope. It charges overnight and releases it slowly.
Look for a model number. It’s usually on a sticker on the back, the bottom, or inside the access panel. Write it down. Even if the sticker is faded, you can often find a PDF manual on the Dimplex website using the model number alone.
Honestly, I'm not sure why manufacturers don't put the model number in a more obvious place. It's like finding the serial number on a cheap printer. But it's the single most useful piece of data you’ll get.
Step 2: Check the power requirements and circuit load
This is where an admin can really mess up. An old Dimplex electric heater (particularly the panel or fan types) can pull a lot of current. A standard 1500W space heater draws about 12.5 amps. If you plug that into a circuit already powering computers, monitors, and a mini-fridge, you're going to trip a breaker. I’ve caused two blackouts in our office that way.
Check what the heater is rated for. The label will say something like “120V / 1500W” or “208V / 2000W.” If it’s a hardwired unit (like a baseboard), there should be a dedicated breaker for it. If it’s a plug-in unit, make sure nothing else on that circuit is running high-draw equipment.
A simple rule I follow: one high-wattage heater per circuit. If I’m plugging in a Dimplex fan heater, nothing else goes into that outlet. That step alone saved me from having to explain to the VP why the break room lost power during the morning meeting.
Step 3: Decipher the controls (with a towel test)
This is where you actually turn it on. But don't just flip a switch and walk away. Old heaters, especially used ones pulled from storage, can have dust or debris inside. I once turned on a unit that hadn’t been used in 18 months—the smell was terrible.
Here’s my method:
- Set the thermostat to its highest setting.
- Turn the timer (if it has one) to “constant on” or “manual.”
- Plug it in or switch on the breaker.
- Wait 5 minutes. If it starts heating, great. If it makes a clicking or humming noise, that’s usually fine. If it smells like burnt dust, that can be normal for the first 10 minutes.
For storage heaters specifically, the controls are backwards from what you expect. You set the input dial (how much heat it stores overnight) based on the next day’s forecast. The output dial (how much heat it releases now) is what you adjust during the day. This tripped me up for a month until someone finally explained it.
Here's a specific tip: if the unit has a manual control knob (like for thermostatic control), turn it fully clockwise first, then slowly counter-clockwise until it clicks. That’s often the “on” activation. It’s kinda like setting a timer on an old coffee maker.
I knew I should have tested the heater before the first cold day, but thought 'what are the odds?' Well, the odds caught up with me when the heating didn’t kick in and I had to rush-order a backup unit. The surprise wasn't the complexity. It was how much time it took to just figure out the UI.
Step 4: Do a safety walkthrough
This isn't optional. An old heater (especially if it’s been in storage or mounted in a forgotten closet) can be a fire risk if you don't check a few things first.
- Is the cord frayed or cracked? Even if the heater works, don’t plug it in if the cord is damaged. Period.
- Is the air intake (bottom or back) blocked? Paper, dust, a stray filing cabinet shoved too close — it’s a bad day waiting to happen.
- Is it on a stable surface? If it’s a portable unit (like an oil-filled radiator), make sure it’s not wobbly. A heater that tips over is a bigger problem than a cold office.
- Is the thermostat actually working? Once it heats the room, it should cycle on and off. If it’s staying on continuously, the thermostat might be stuck.
I have mixed feelings about using older equipment in general. On one hand, Dimplex makes solid stuff—some of our storage heaters from the 90s still work fine. On the other, safety standards have gotten stricter. For example, modern units often have automatic shutoff if they tip. That’s a feature I’d look for if you’re buying replacements, not just operating old stock.
According to the FTC (ftc.gov), product claims about safety features need to be truthful. So if you’re sourcing new units and they advertise “auto shut-off,” check that the model actually includes it. A cheap knock-off might look like a Dimplex but lack that safeguard.
One more thing: if it’s a chiller unit, ignore everything above
This guide is for heaters. If your “old Dimplex” turns out to be a chiller (for a server room or a lab), the controls and maintenance are a completely different game. I can only speak to domestic operations (office heating). If you’re dealing with a cooling unit or a complex thermal system, the calculus is different and you should consult a tradesperson, not an admin’s checklist.
That said, for 90% of office spaces with a wall-mounted or portable Dimplex heater, these four steps will get you through the first day. Write down the model number. Check the circuit. Test the controls. Do a quick safety check.
Then get that room warm before the lunch meeting.