We have had several customers who have been turning there stats down to 70* in the 100* heat. The loop temp has gone from a normal 80 - 90* to 110 and then shutting down on high head . Anybody else been getting these calls. We have had to put a timer on there second stage and then keep there stat at 74 or 75 to keep there loop temp down.
Periods of extreme heat or cold will allways shine a light on a design that " was a little too tight ". I took 2 calls yesterday concerning poor performance in cooling due to increased ewt. Your timer work around for stage 2 is a real gem for preventing a shutdown!
How long are the loops and what size units are these? Eric is right, sounds like a slight design flaw for the units that leads to big problems.
I agree with the previous posts as well. If these are horizontal loops, you may be able to bandaid the problem by using a soaker hose over the loop ditches. Here in TX where only about 1% of the loops are horizontal, last year was pretty hard on all systems but the horizontal suffered the most. When the soil dries out, it loses a lot of heat conductivity especially if it cracks and loses contact with the pipe.
I have two systems installed at my home to measure performance of each and last year with ambient temps >100 for 40+ days, my horizontal loops reached 96 EWT in late August and the vertical only got to 84.
Right now with temps only in the high 90's, the horizontal EWT has reached 78.8 and the vertical is 73.5....but it is not late August yet.
Photos show EWT for package unit - horizontal and EWT for split - vertical
One in paticular is a Geo Comfort m#GTC060A11CD . This is a split system with vertical loops. As far as if my boss installed them correctly I honestly have no doubts in his Craftmanship to detail when it was put in but I wasn't there. The only customers who have had problems are the ones who leave their system on 80* and when they come back from vacation they crank it down to 70.
It has been my experiance that the root of most geothermal performance issues all go back to the "art of implementing a good load calc". Even if the load calc was a thing of beauty it still does not take into account the flooky changes in weather a lot of the country is seeing, in both heat and cold.
We over loop due to the low cost to do so, but sometimes it is still not enough to carry the system in extreme cases. I am assuming you have been through the rest of the machine and everything is golden? Ductwork as well?
One of my biggest headaches went back to a return trunk line in an uninsulated attic space that was allowing cold air into the system:gah:.
Finding that issue caused me a lot of grief untill we got to there.
You bet. I have come to find out that we have had other problems with this system in the past. Leaking shreader valves , leak in the loop. (I had to charge up the loop when I went on this call couple weeks ago) I sure do like the closed loop non pressurized loops better. We have started installing nothing but these now.
Thanks for everybodys input.
Here it's the other way around, a hard winter will get the loops down into the low-mid 20's. Even with a hot summer the loop temps barely get over 60°
We use the loop sizing program from Geocomfort and haven't yet had an under performing loop.