Steps for a good A2W heat pump replacement

kaygeemaine

Would you flush and replace antifreeze, (Cryotek) in an air to water heat pump replacement (initial install 10 years ago). Older unit had 2 condenser failures.

EBEBRATT-Ed

You can test the glycol it may have become acidic. I would cut open the old condenser and see why it failed.

If the water and glycol is 10 years old and with failures I would change it especially with a new unit. Start fresh.

GW

unsure how the two relate- two compressor failures and 10 year old antifreeze. The pressures and temperatures dictate a healthy or poor running refrigeration cycle. And some other factors like short cycling, acidity

you have a 10 year old air to water system? Maybe you mean traditional outdoor unit with basic air handler with hot water coil?

Curious what you have, air to water is just now getting momentum.

kaygeemaine

We have a SpacePak LAHP48 and planning on a new Solstice CC32-60. Parts and service on the original were deemed not available/practical. Don’t know what caused 2 failures and don’t know if we’ll get a post-mortem. Just trying to confirm that a new unit deserves (requires?) a system flushing and new glycol. All other components seem in good shape. We seem to have been early adopters.

GW

wow that’s gotta be the fist one off the line!

(I don’t know anything about Spacepak)

hopefully your new system works out well

AllShorePlumbingNY

Definitely flush and refill with fresh Cryotek. Ten-year-old glycol after two condenser failures isn’t something I’d trust with a brand-new unit. I’d also do a proper hydronic flush before refilling so any sludge or debris from the old system gets cleaned out. Worth checking the pH of the old glycol too degraded glycol can get acidic over time and become hard on heat exchangers and circulators.
Congrats on the Solstice upgrade too. Early A2W adopters definitely took some lumps figuring these systems out.

hot_rod

Also consider running a hydronic cleaner through the system. When glycol breaks down it can leave a sticky residue on the piping and components. A cleaner will return the components near new condition.

Most often it is high temperatures that break down glycol, but the inhibitors in the glycol get used up over time. The color and smell is a good indicator of bad glycol, dark coffee color, harsh bitter smell.

Glycol can be recycled if you take it to quick lube shops, or most auto parts suppliers, both PG and EG can be recycled

kaygeemaine

I'm a goose…it was one confirmed —>compressor (not condenser) failure at 5 years, and the second failure at almost 10 years was frosting over and tripping out. One tech who didn't take the replacement job (parts are n/a) said fluid had sprayed internally. So, no diagnosis at this point. Also, it has sat idle since Christmas, the pressure on the system is at zero. Another tech said glycol pH was reading somewhat acid (I don't know the number) and fluid looked darkish orange and had a small amount of dirt/debris. The concentration was on the low side for our zone. No wye strainer in the system. The new contractor preparing to install new A2W heat pump was not initially planning on a flush and fill with new glycol. I'm looking for guidance.

Thank you (all) for your replies!

hot_rod

If you go to most any glycol manufactures website, they had guidance for glycol care and replacement intervals. Here is the Dowfrost PG page. Other or unknow brands would be tested to the same criteria.

You can send a sample to the manufacture or a lab if you want to know everything about the fluid.

For the amount you are talking about, replacement after a cleaning makes sense to protect the new components and maintain warranty.

Ph is a very simple test you could do as the starting point. Test strips or kits are not expensive. Below 8 ph indicates time to replace.

Glycol blended on site need to be with deionized water, not tap water.

Kaos

How many gallons are in there? I think swapping out the glycol after a decade is pretty cheap insurance with a new system, I would start fresh.

The unit will be circulating hot water all winter long, there is no need to have a very concentrated solution. Unlike snow melt, with AWHP, you only need enough glycol for burst protection in your climate, so it saves you some additional cost.