Blog: No User Serviceable Parts Inside By: John Heisz

To heat my shop, I bought this “heavy duty” construction heater:

And had this problem with it:

Copied from the product description on the website of the store that I bought it from:
“The Dimplex heavy duty construction heater provides maximum durability for work site conditions where temporary heat is required. The powerful, 160 CFM fan delivers quiet operation and rapid heat-up. It also offers thermal protection for complete safety.”

I took the liberty of highlighting the phrases above in bold.

Here’s the situation: I bought the heater ($100 plus tax) back in October to use in my shop, but didn’t get a chance to connect it until the first week of November. To avoid some extra complications and expense, I wired it directly into a box that has a double pole thermostat:

The box in the wall was originally for a 240V outlet, but in it’s place I put a cover plate and a regular duplex box for the thermostat. The cable from the heater enters the side of the box.
Of course, to do this, I had to cut the plug end off of the cord.
I do remember thinking at the time: “what if the heater breaks? I won’t be able to bring it back”. But, as usual, gave myself permission to go ahead, saying: “Nah, it won’t break because you already thought of it”.

Well, it broke.

It melted, actually. The paper thin blade connector burned clean through, as shown in the video above. Here’s a close up of what was left:

Those insulating covers are silicone. They burn too, apparently.

Now, I’m not going to speculate as to what caused this, other than to say that if it could possibly live up to the assurances given in the product description, it should have been better built. These flimsy fast-on connectors are obviously not up to the job.

So, what am I left to do? Fix it, or throw it away and buy another one for another month of heat?
Before going any further, I’ll say that I’m just posting this to vent a little and show what I did to get this heater working again, and that I’m not recommending you all go out and do the same. I often watch movies where the main character scales the side of a tall building with just suction cups as hand-holds, yet I manage to resist the temptation to do that myself.
Also, my direct wiring of the heater into the box with the thermostat was not the reason for the failure, so lets break that bubble right now.

I elect to fix it. First thing I did was flatten the female blade connectors and give them a good cleaning. I then cleaned what was left of the male (gelding, by another name) and bent the females around it to make a good connection:

Then I took some scrap copper pipe and cut out a thin strip, flattened it and cleaned it.

The copper strip was then bent around the other part and crimped on tight:

I isn’t pretty, but it is substantial and it should hold:

Running the heater with the repair and it’s as good(?) as new.

A massive dab of high temp silicone to keep the wires in place in the unlikely event that the new connection fails:

A better look at the silicone insulators. I guess copper evaporates at a pretty high temperature.

Seems like with each passing year we are getting less and less for what we pay. Some say it’s our own fault – by buying the lower cost products, the “better made” ones need to reduce cost to compete. There’s a lot of truth to that, but it is only part of the story. The real driving force behind reducing cost is to increase profit. It always has been.
In the case of this heater, I believe the best connection is the one that has been used for years for this type of application: a terminal connection, with a screw or nut to hold the wires together. Any connection subjected to repeated heating and cooling will be stressed, and the proven method doesn’t rely just on friction and the spring tension in a thin piece of metal to hold it together.
Of course, that’s more expensive in terms of parts and assembly time.
Less cost, more profit, and I get to waste an hour of my time repairing something that shouldn’t have failed in the first place.

If you have a few years under your belt, take a good look around at how things have changed, especially in the last few years. Some of the cagier manufacturers will pass off the shoddy workmanship as a way to be more “environmentally responsible”, reducing their “carbon footprint”. How much fuel would I burn bringing the defective product back to the store where I bought it? What about the replacement cost and environmental damage from potentially burning down my workshop?
The kicker (there’s always a kicker) is that I didn’t go looking for the cheap product, but bought the one with a known brand, in a major retail store and not for an insignificant amount of money. Seems that I probably would have been better off getting one for less money, at least then I wouldn’t feel so taken advantage of when it fails.