3/4" to 1 1/4"

Roughly with thermometer taped on PVC pipe with 2" of insulation over it EWT is 60 and LWT is 66. The unit doesn't have to run very long to satisfy the thermostat.

 

This is the reason why you are not getting much hot water.

 

60F loop temp should be warm enough to kick on the DSH logic. But as Dewayne said, your runtime might also be too low to contribute significantly. In addition, DSH contribution is much less (roughly 50%) in A/C mode.

 

Loops are heated up now and making hot water. Also run time is extended since these 98 degree days.

 

great. yes, some DSHs need warmer loops to kick in.

 

What kind of a guage do you need to measure the amount of methanol U have in your loop? How low do U have to have to keep it from freezing up?

 

http://www.amazon.com/Thermco-Specific-Gravity-Plain-Hydrometers/dp/B00M9LCLF0

 

Is this the tool to use for glycol concentration in closed loop also?

 

no, there are several ways to test glycol. Google can point you in the right direction.

 

Thanks Dewayne . I have one ordered.

 

What kind of a reading will you get measuring methanol content with the hydrometer?

 

That hydrometer listed above (ASTM 89H) does not have the proper range to measure the specific gravity of a water-methanol solution. That model has a range of 1.000 (pure water) to 1.050 (more dense than pure water, i.e. propylene glycol anti-freeze has a specific gravity of 1.036 at 25C). The density of methanol is less than 1.000; therefore, a mixture of methanol and water will have a density of <1.000.

For methanol anti-freeze solution, you need an ASTM 88H hydrometer with a range of 0.950 to 1.000.

The following graph shows the density of methanol-water solutions at various percentages and temperatures. This graph only goes down to 20% methanol on the low end of the percentage range. 20% methanol will provide freeze protection down to ~5 deg F. This graph shows density in g/ml, but pure water is used as the reference for specific gravity which has a density of ~1.000 g/ml (actual value is 0.998) at 20 deg C (68F); therefore, the density scale equates approximately to the specific gravity scale.

http://www.methanol.org/Technical-I...mation/Densities-of-Methanol-Water-Mixes.aspx

As an example from the above graph, a 20% concentration of methanol in water would have a density (g/ml) / specific gravity of 0.970 at 10 deg C (50F)

From an old CRC handbook, methanol-water solutions (percentage by weight) have the following specific gravity at 60F:

10% Methanol = 0.983 Specific Gravity
15% Methanol = 0.976 Specific Gravity
20% Methanol = 0.968 Specific Gravity
25% Methanol = 0.960 Specific Gravity

 

Nice Arkie.

Thanks

 

Good catch Arkie !!

 

Well, after almost two years of 72 degree air in the winter and 78 degree air in summer I have had my first hic-cup. Unit would run but no cold air. Call in serviceman and here he comes with his guages in hand. After arguing for a while about checking freon he got my papers on the unit and called factory rep. Told rep what unit was doing and he pointed him to a board with blinking green light. Took air tank and blew out drain line, turned unit on and it ran like a charm.
From now on every spring and fall I am cleaning out that drain line.
I want to thank everyone on this site for all their help to me and everyone else. I think I read every word here for about two years before I took the plunge. Every question that ever came up had already been answered for someone else and I had read it. The install was just as simple as putting in a refrigerator and hooking up the ice maker.


Thanks again

Bill Davis

 

I know this is an old post, but I am puzzled by the response. We are in the process of designing a system, and I was going to oversized the ground loop to reduce pumping losses. Also, it would seem with a larger diameter tube there is more surface area in contact with the soil, which should improve heat transfer. Why would flow rate need to change with a larger tube - it would seem as though the heat going into the loop from the condenser is independent of tube size, the surface area of the loop increases by pi x the diameter change, so the water leaving the ground loop should be closer to the ground temperature with a larger diameter tube and the same flow rate (in gpm)? What am I missing?

 

It's a surface area to volume ratio that is better for heat transfer with smaller pipe.

Flow rate doesn't have to change. Your heat pump wants what it wants for flowrate. But if you're a stickler and want to maintain turbulent flow for better heat transfer it has to change.