Diesel heater sizing

[arctictraveller]

So, I bought one of the inexpensive Chinese diesel heaters, but mistakenly got the 5K btu model when I really wanted the 3K btu one. I've heard that the bigger ones can be too much in less than really cold temps, so I wonder if anyone has experience with this. I can just order the smaller one, but I wonder if I should install the bigger one to try. Anyone?

[REF]

From what intel I gathered, at least on the Espar, the larger units would heat up our relatively small space in the van rather quickly and they’d never really get up to proper working temp, which can cause the unit to soot and foul.

[86Scotty]

I had a 5k (Planar) in my Transit. It was fine. It gave me no trouble for the couple years I had it and heated the space and cycled just like any furnace.

I have been running an Espar D4 (4k) in my work truck for the past 3 years and it does fine also, not too much, not too little.

[Youngster]

Originally Posted by arctictraveller

So, I bought one of the inexpensive Chinese diesel heaters, but mistakenly got the 5K btu model when I really wanted the 3K btu one. I've heard that the bigger ones can be too much in less than really cold temps, so I wonder if anyone has experience with this. I can just order the smaller one, but I wonder if I should install the bigger one to try. Anyone?

They are cheap. Mount it up and run it. If it's too much heat swap it for a 2kw heater. All the mounting is the same between the 5kw and 2kw. The 2kw has a smaller body so it would drop right into place.

FYI, there are only two physical sizes of the CDHs: 2kw and 5kw.
Everything sold larger than 2kw is really a 5kw with tuned-down (3kw, 4kw) or tuned-up (8kw) air/fuel settings. The way to tell is to check the dimensions of the unit. The measurements in the attached graphics are not exact for every unit but close.

Many more 5kw units are made, 2kw are harder to get. Many suppliers sell 5kw units as 2kw. Carefully reading the product description for the heater dimensions is key to finding the size heater heater you're after.

A 5kw tuned-down to 3kw is more problematic than a straight 2kw or 5kw heater properly tuned for it's size.

A 2kw will be plenty for an Econoline with hard top. With a penthouse in cold weather a 5kw might be best. It's always better to open windows to cool off using a 5kw than it is to wish you had more heat with a 2kw.

[Youngster]

Originally Posted by REF

From what intel I gathered, at least on the Espar, the larger units would heat up our relatively small space in the van rather quickly and they’d never really get up to proper working temp, which can cause the unit to soot and foul.

This is true for the CDH units also. Opening windows (if situation allows) helps mitigate this by running the larger unit hotter.

[shenrie]

Anyone have an idea on fuel consumption difference between the 2k vs the 5k?

[Youngster]

Something I found on one of the CDH Facebook groups

[arctictraveller]

Originally Posted by Youngster

They are cheap. Mount it up and run it. If it's too much heat swap it for a 2kw heater.

Thanks for all the input guys. I agree that they are ridiculously cheap, enough so that I suspect that once one begins to fail, rather than investing money in parts, a whole new unit may make more sense, and they are certainly less expensive than just a couple parts for the originals like an Espar or Wabasto. So, thanks again, I think I'll just install it and see what happens, and if it does end up carboning up, I'll still have my original Suburban propane unit since I don't trust the diesel heater enough yet to be my sole source of heat.

[Youngster]

Bench test it 1st before you commit to installing it.

A common problem is that the fan is shoved too far back into the housing and catches, sliding it out on it's shaft so there is 0.5mm clearance with the housing fixes this. Also the fan can be too far out on the shaft, slide it in to 0.5mm clearance with the housing. Otherwise the fan won't push enough air past the heating body.

[86Scotty]

Originally Posted by shenrie

Anyone have an idea on fuel consumption difference between the 2k vs the 5k?

Shenrie, these things use so little fuel it would be a non issue. You'd probably be talking 15 oz. per night vs. 16 oz. If you have it plumbed to your van tank you could run it for weeks and still not notice much difference from your main tank.