Heliodyne DYN-O-FLO Heat Transfer Fluid - Propylene Glycol Right?

matt_sunwaysolar

I'm servicing a Heliodyne H-PAK system that was installed by others. It needs some additional heat transfer fluid, but Heliodyne has a very clear warning in their install manual about only using "DYN-O-FLO HD Propylene Glycol". Anyone out there know if this is a real warning to heed or if another high-quality propylene glycol will work just fine. I typically use Noburst HD P.G. and tend to assume we're talking about apples to apples here. Anyone have any firsthand knowledge or experience? Please advise.

Thanks.

hot_rod

If you can find a solar specific PG that would be best, they have a bit higher temperature rating.

If not any of the HD fluids would be ok, DowfrostHD, NobelHD, Hercules Cryrotech, Rhomar, etc.

Tyforcor is another brand sold under a bunch of solar labels. Caleffi has a corn based bio-solar fluid.

Some brands sell concentrate if you need to boost the freeze protection level. I use the RhoGard Ultra concentrate for adjusting. It only takes a little to boost a weak solution up, depending on the volume.

Check the ph of the fluid in the system first. New glycol will run 10.5- 11 or so. If it drops into the 7's ph I would flush and start over with all new fluid. it probably doesn't hold all that much.

matt_sunwaysolar

Ok. Anyone know if DYN-O-FLO HD is compatible with NOBURST HD for use in solar thermal systems? Any reasons it wouldn't be?

Jack

Is "compatable" what you want, or would you prefer to drain, flush and replace with new fluid. Reason I ask is I just saw a job that had old glycol and a new modcon was installed without flushing, cleaning the slab tubing and re-charging as directed by the manuf. It is a freakin' mess and a service problem. I would suggest a clean start. Long run everyone will be happier.

hot_rod

matt_sunwaysolar said:

Ok. Anyone know if DYN-O-FLO HD is compatible with NOBURST HD for use in solar thermal systems? Any reasons it wouldn't be?

My guess would be yes, it would be compatible. The color and smell of the fluid is another indicator. If it has a bright color and a sweet smell it is probably fine to keep the old fluid and add to it.

Dark brown, sharp smell, get rid of it.

You can actually blend EG and PG, but you end up with a fluid of unknown toxicity. Best to stay with PG based fluids.

If you do drain and flush large quantities, recycle it at a Quick Lube shop or auto repair dealership.