Closed loop, 5 ton Envision, 3000 ft horizontal loop - buried 4ft deep in heavy clay with very high water tables. Current loop temp read today was 28.6 In and 26.3 out. Temp outside is -20C How much effect if any does clay have on the operational effect of the loop, or is it just the over depth that matter?
The soil type and the moisture content both affect the conductivity. The attached chart lists the types from highest to lowest.
side note Given a delta-T of only 2.3 deg F across unit, system may be substantially overpumped - flow too high. This costs efficiency owing to excessive pump power. It is possible that high flow is needed to maintain turbulence in loop, but I would hope the loop was designed to not need that. -20 C implies pretty cold climate, so loop temps, while low, may not be too bad. That and given the weather, the unit has probably been running at greater than design load for days.
Last night before installer left after flushing system, the thermostat gave a "sensor error" but he repower'ed it and that went away. However, the system ran all night and I awoke to a very confused theromostat! I have a Waterfurnace 96P684-01 with factory default settings except set to non-programable. The temp on the thermostat is fluctuating between 17C to 20C within a few minutes of itself back and forth (have it set to achieve 22C). It says it's running Aux 2 all the time with fan, but the installer disabled the Aux dip switch and the air out the vents is very cool. The thermostat manual has tons different options of settings - i really just want a basic constant temp 24hrs a day - should any of the factory defaults be changed to obtain that?
Thanks - so how would the depth effect all of this? ie. if soil was the most favourable, would it matter if it was 4 feet or 6 feet?
On a 8 ton system in Montana, a 4' deep loop would need 1660' of trench to provide min EWT of 30° a 6' deep loop would need 1105' of trench to provide min EWT of 30° a 6' deep loop with 1660' of trench would provide min EWT of 34°
