WorldWide Drilling Resource

The Third Loop by Peter Tavino Litchfield Geothermal Dr ng contractors have gotten much better at nsta ng ground heat exchanger oops. Heat pump compan es have a so mproved the r refr gerat on oops. So et's check out the th rd oop n our geotherma systems: a r c rcu at on n the duct oop. My attent on to t was recent y sparked when a 6-ton heat pump retrof t served by tw n c osed- oop, grouted boreho es d d not funct on proper y. Rep ac ng the 10-k owatt (kW) aux ary heater prov d ng on y 34,121 Btu/hr = 2.84 tons, w th a 15-kW heater @ 51,182 Btu/hr he ped a ot. There was a so a oose-set screw n the f rst f oor damper not respond ng to the contro s gna , but we suspected someth ng was st awry when the basement cont nued to be too warm. The homeowner and I watched some how-to v deos show ng the proper app cat on of duct mast c paste, but oca stores d d not carry t; and fo tape appeared su tab e. We cut off the nsu at on at the p enum supp y ducts near the heat pump, wh ch were or g na y nsta ed 20 years ago when the house was bu t. We were amazed at howmuch hot a r was b owng out between the seams and open ngs. Us ng fo tape (not duct tape, of course) we sea ed each crack and rep aced the nsu at on. What a b g d fference t made, because the very hottest a r was be ng ost before t cou d enter the cond t oned rooms upsta rs. Return ng to my own house (wh ch was prev ous y tested for eakage and was okay), I opened a few adjustab e reg sters and gr es. Sure enough, there were one-e ghth- nch spaces between the meta vent boots and the f rst f oor p ywood f oor, and the meta vent boots and the second f oor ce ng drywa . Us ng my own nexpens ve ro of fo tape, I sea ed each boot as shown n the p cture. Now there s much better f ow of hot (or coo n summer) a r across the gr es and reg sters, w thout eakage. Second y, when the heat pump s not runn ng, I am not eak ng warm a r up nto my unheated att c or down nto my unheated basement. When ca cu at ng heat oss and ga n ca cu at ons by ACCA (A r Cond t on ng Contractors of Amer ca) J methods, c ents are amazed to see they can be oos ng as much heat through duct eaks and poor duct nsu at on as they do through ce ngs or wa s. So perhaps for a qu ck do- t-yourse f project n any home or bus ness bu d ng, a s mp e nex- pens ve ro of fo tape can mprove these ca cu at ons. Bes des sav ng heat ng and coo ng e ectr c ty costs, there s another benef t. The meta vent boot now secured to the p ywood f oor or sheetrock no onger v - brates. The pu sat ng, humm ng sound I endured each t me the system ran, s gone. The obnox ous meta drum no se has been fo ed! The statements and comments in this article are based on information and references believed to be true and factual. If you have any questions or comments please forward them to me in care of WWDR . Pete Peter Tavino may be contacted via e-mail to michele@ worldwidedrillingresource.com 55 WorldWide Drilling Resource ® APRIL 2016