How many heat exchange tubes should be in the HydroFlex boiler?

[jervine10]

I bought a Harman HydroFlex a couple years ago. For someone else who has one, how many spiral heat exchange tubes came with yours? I have 14 slots, but it only came with 8 tubes. I'm asking because I've seen literature and documentation for the boiler that make it seem like they should all be filled with a spiral tubes.

Here's one link that makes me wonder:
(broken link removed)

Thanks!

 

[maple1]

You mean turbs? As in turbulators?

Sounds like the 14 'slots' are the tubes - turbs are the things that go in them.

That doesn't answer your question though.

Sort of on topic though - my boiler has 6 tubes, 3 long & 3 short. It comes with 3 long turbs. I cut one of them in half. I vary the amount of turb with the season & weather conditions - mid winter cold usually = all of them, burning in summer maybe only 1. That's because amount of turb will affect the amout of draft the fire sees. If I put all my turbs in in the summer, the fire wouldn't burn very good. But mine is natural draft, that may not be an issue with forced or induced draft. Hopefully someone will come along that can answer your question.

 

[jervine10]

Turbs is exactly what I was trying to describe! Thanks for clarifying that for me!

So it sounds like it's possible that I should have only received 8 turbs. Does the position of them make a difference I wonder? They originally came placed on the perimeter of the boiler. What if I moved them to the inner slots?

 

[maple1]

Not sure. Nothing in the manual? Or maybe you don't have one?

I would maybe expect it should have a turb for each tube, in a forced draft (this is a pellet boiler right?) situation - just guessing though.

With more tubes than turbs, I would likely try to get them in the path of direct flue gas travel between the tube area & the flue. E.g., if the flue pipe exit is directly over the middle area of the tubes, I would get turbs in the middle area of the tubes. If you don't, the flue gases will have a more direct path to the flue so less chance for heat transfer before the gases exit.

Generally thinking....

 

[jervine10]

Yes it is a pellet boiler. I do have a manual. I should see if it has an item listing in it.

As for position, that makes perfect sense! The exhaust is more toward the center. I should try that. I wish I would have known to try this two winters ago =)

 

[jervine10]

Good advice with the manual. It does actually say it comes with a package of 8. So I suppose placement perhaps becomes the experiment.

 

[velvetfoot]

This came up a few years ago. I believe it's because there was too much heat transfer with all turbulators installed.

 

[velvetfoot]

Here was a thread I started. VT_Bubba is very helpful.
https://www.hearth.com/talk/threads/harmon-hydroflex-60-pellet-boiler.81612/