.

Why would anyone use Cryotek 100 in a geo loop? It's specifically
formulated for systems with aluminum heat exchangers.

BTW, "only 60% glycol" doesn't tell you anything about its freeze
protection properties compared to 100% glycol. Unless the other
40% is mostly water, the mixture might provide better protection
than pure glycol. It all depends on the average molecular weight
of the non-glycol ingredients.

BTW2, Hercules Chemical is no fly-by-night outfit; they're a major
chemical manufacturer with serious professional expertise.

Looby



BTW: Standard cryo-tek products, incl. cyrotek-100, should not be used in systems containing aluminum and operating above 160°F/71°C. Cryo-tek -100/AL is available for aluminum systems.

But at this stage we do not even know if it was cyrotek. I am simply suspecting this. Why? Because the same supply houses which carry heatcontroller heatpumps carry cyrotek.

What's the best way to get anti-freeze?  (Apart from putting her outside without a coat)  Stick a little tube in the p/t port and drain some?

Yep.... Should be no problem with 70 psi pressure.

K. I'll try tonight to get some out, put it in the freezer with a thermometer and try to see when crystals might form. I also emailed my original HVAC guy to see if remembers what brand anti-freeze he used.

Posted By stuart.wyss on 20 Dec 2010 01:41 PM
K. I'll try tonight to get some out, put it in the freezer with a thermometer and try to see when crystals might form. I also emailed my original HVAC guy to see if remembers what brand anti-freeze he used.

So where is your original installer...and why isn't he camping out at your place right now until it is fixed?

It was Propylene Bio glycol.

Posted By stuart.wyss on 20 Dec 2010 03:32 PM
It was Propylene Bio glycol.

Do you have a brand name? The point here is that likely your heatexchanger is freezing up, and not all antifreeze mixtures are equal. The confusion in my experience comes in when the installer uses a brand name which does not contain 100% propylene glycol, thus he accidently mixes the antifreeze in the incorrect ratio with water which does not give you the correct freeze protection.

Yeah, I looked it up and that wasn't the brand...I've emailed him for the brand name. 

Thinking about "winterizing" with my system...last year it locked out several times.  Just took temp readings a little while ago (and pressure) directly on the PT ports - Pressure was 68 and 74.  Temp was 33 IN and 28 OUT.  That's cold.

Because I have an AirTap water heater which, to operate, takes heat out of the basement (basement not insulated, neither is the ceiling of basement), I'm thinking about turning off the AirTap for the season and switching the electric coils back on. 

I'm also thinking about disconnecting (electrically) the desuperheater.  During all of this, even now with the 33 and 28 in/out, the desuper is providing hot water...it's running, I checked.  I know some people install a switch to electrically cut the desuper in winter, basically working like the built-in cut-off thermostats on the desuper lines.  I'm wondering, as long as the water stays connected, would this make a difference in both the potential freezing of the unit and/or the effectiveness of heating the house?  It might only be a couple thousand BTUs, but I'd take a couple 1000 more to heat the house, especially if the electric coils are doing the hot water now.  The desuper would be left plumbed to the buffer tank.  Haven't done any of that, just posing!

Sounds like a reasonable plan.

Posted By stuart.wyss on 20 Dec 2010 08:42 PM
Yeah, I looked it up and that wasn't the brand...I've emailed him for the brand name. 

Thinking about "winterizing" with my system...last year it locked out several times.  Just took temp readings a little while ago (and pressure) directly on the PT ports - Pressure was 68 and 74.  Temp was 33 IN and 28 OUT.  That's cold.

Because I have an AirTap water heater which, to operate, takes heat out of the basement (basement not insulated, neither is the ceiling of basement), I'm thinking about turning off the AirTap for the season and switching the electric coils back on. 

I'm also thinking about disconnecting (electrically) the desuperheater.  During all of this, even now with the 33 and 28 in/out, the desuper is providing hot water...it's running, I checked.  I know some people install a switch to electrically cut the desuper in winter, basically working like the built-in cut-off thermostats on the desuper lines.  I'm wondering, as long as the water stays connected, would this make a difference in both the potential freezing of the unit and/or the effectiveness of heating the house?  It might only be a couple thousand BTUs, but I'd take a couple 1000 more to heat the house, especially if the electric coils are doing the hot water now.  The desuper would be left plumbed to the buffer tank.  Haven't done any of that, just posing!

Stuart, the minimum EWT (water in) should be around 30 degrees F, and nothing will happen if it drops down to 25F. The absolute minimum specified by the manufacturers is 20F. Leave the desuperheater on, it is the cheapest way to heat your water. The units should be maintenance free, as long as your antifreeze is correct. It should never freeze up, and you do not need to take any action. DSH use about 10% of the BTUs generated and shut off automatically when the tank reaches 125-130 F. Fix your antifreeze, and then let it run for the rest of the winter!

Yeah, but the antifreeze thing isn't going to get fixed for a few weeks.  Until then, I'm supposed to monitor temp and pressure daily, and note any problems.  Probably the antifreeze *will* get redone, but until then, is there anything I can do to slow down any possible freezing/heating issues.  I thought maybe getting rid of the AirTap for a while would certainly help keep the basement warmer, since the AirTap does come on as a finishing heater.  I hoped that by electrically disconnecting the desuper, that more heat would be available to go through the main exchanger and perhaps reduce the possibility of a freeze.  I just wanted to make sure I can do it without damage to the system.  I won't shut off the water pipes that go into and out of the desuper.

I will definitely keep everyone posted about the situation.

Last night again, the pressures were 74 and 68, when normally they've been in the 40s.  Could ice that's beginning to form in the fluid cause a pressure increase like that?

Oh, my original installer doesn't recall the brand name.  Just that the glycol came in black 55 gallon drums.

Shifting both direct and indirect load off the heat pump will help, so dump both the Air tap and Desuper. Does the Desuper have a stop switch...WF Envisions do.

If using setbacks, consider stopping that - long runs during recovery temp may temporarily depress loop to the freeze point. Steady thermostat setpoints result in intermittent heat pump operation during all but the coldest weather. The off cycles should allow some recovery as well as possibly letting incipient ice melt away. When a unit stops, refrigerant pressures equalize, and that process should draw warmer refrigerant into the coax, melting small amounts of ice.

I wouldn't be real pleased about a "few week delay" to fix the AF problem considering the worst of the heating system is likely to occur in "a few weeks"...ask installer how they feel about sharing the cost of aux strip operation and resistive water heating in the meantime. In your shoes I'd be up on my hind legs raising Cain.

Thinking about it, the desuperheater in general takes away heat from the load coil, but would not reduce the heat extracted from the water, thus not reducing any chance of freezing. The only thing you can do to avoid freezing is to not run the unit.

Still cannot explain the pressure. Delta seems OK. What is the pressure when you shut off the system?



'Oh, my original installer doesn't recall the brand name. Just that the glycol came in black 55 gallon drums.'



That suggests that he did not pay attention to what is in there. You can take the initiative and call his supplier. How is your antifreeze doing in the freezer?

That suggests that he did not pay attention to what is in there. You can take the initiative and call his supplier. How is your antifreeze doing in the freezer?

I've emailed who I *think* supplied all the tubing to see if they also did the antifreeze. Not sure who his supplier actually was, but I'll chance it was the same company. Haven't done the freezer thing yet. Will do tonight.

I have reduced the setbacks to only 2 degrees per zone. There is no switch for the desuper, but I could unplug the main feed wire from the circuit board -it's a spade terminal. It would easy enough to add a "light switch" to the side of the cabinet and make it "official".

DJ

I agree with your reasoning but take one thermodynamic step back: If DSH skims off 10% of system heat, then system must run 10% longer to meet rest of house load. The loop water temperature depression brought on by every system on cycle then has 10% longer to drop down to freezing. Stated another way, total heat extracted from the loop rises 10%. Either way, the loop gets a bit cooler then it would have otherwise. DSH water heat is cheap but not free in winter.

Stu - stay on 'em

Cycling the unit more often will help to keep the loop temps higher.
I looked up one of our installs , and the DSH pump turns on after a shower and then turns off when the buffer tank reaches 120F. When it runs, there no decrease in the Leaving Water Temperature, not even a 10th of a degree. However, the leaving load temp drops by about 2 degrees under load. You can see yourself, the link is below. All in line with the thought that shutting off your DSH will not change the heat extracted from the loop, and not prevent freezing. The only thing it will do is satisfying your house load quicker, thus reducing run time slightly. But you do all the worrying about the DSH, I am with Curt, I would be up in arms trying to get the root of the problem resolved. Otherwise you might be in a no heat situation soon.
http://welserver.com/WEL0267/

Thanks, guys. I've been emailing my new HVAC guy about the "unidentified" anti-freeze. The day that it did lock-up, we were able to put emergency heat on set at 65, and fired up the pellet stove. It got to 80 in that room, and with fan-mode on, the 'excess' heat was moved around the house somewhat. We definitely won't be without heat, but I agree, I'd rather get this properly identified and solved sooner rather than later.

I think I've written this before, but I'm always nervous about jabbing the big old meat thermomter into the p/t port. It's such a tight fit. I need to find one with a tapered end.

Posted By engineer on 21 Dec 2010 12:59 PM
DJ

I agree with your reasoning but take one thermodynamic step back: If DSH skims off 10% of system heat, then system must run 10% longer to meet rest of house load. The loop water temperature depression brought on by every system on cycle then has 10% longer to drop down to freezing. Stated another way, total heat extracted from the loop rises 10%. Either way, the loop gets a bit cooler then it would have otherwise. DSH water heat is cheap but not free in winter.

Stu - stay on 'em

Agreed. Our posts were just overlapping. Current heat extraction is not gonna change, but total heat extracted is, thus a higher load on the loop. On the other hand, depending on the climate, the buffer tanks reach their peak temperature quickly. My DSH pump runs maybe 6 hours a day and shuts off the rest of the time since the tank is satisfied. So not 10% get diverted to the buffer, but about 2.5%. I would think the impact on LWT is rather minimal.

Cooper DFP450w has a very sharp very narrow tapered tip. The probe location is in the tip of the tip. $30 at Amazon

It is the cat's backside for Pete's Ports!

I have an 80 gal buffer on an Envision 038 locked in low stage. I've never had the DSH pump go out on high temperature. Max tank temp I've ever read is 129

Posted By engineer on 21 Dec 2010 02:19 PM

I have an 80 gal buffer on an Envision 038 locked in low stage. I've never had the DSH pump go out on high temperature. Max tank temp I've ever read is 129

Again, here is the link.
http://welserver.com/WEL0267/
Specifics are that it is a 6 ton Synergy and a 10 ton load with a 50 gal buffer tank, right now running 24/7 since the balance point is around 32 degrees F. Below that it is supplemented by a natural gas boiler. So smaller tank, twice the size heatpump, different dynamics than Florida.
http://welserver.com/WEL0288/ Same here. Weekend house, kept at 62F right now, 50% runtime in first stage, 6 ton unit, buffer tank is around 130F, DSH pump barely turns on. I prefer smaller buffer tank reaching top temperature quickly. For the WEL267 system above, the DSH took care of all the hot water needs for the last 2 months. The heater for the finishing tank did not turn on since the end of October. Six head family.