Folks, We have a puzzler on our hands - a GeoFurnace Mfg Mtex Series Model MC048tR12TLCT. This is a two stage package unit with rare capability to direct full capacity to hot water calls. Accordingly it features 3 Coax heat exchangers (loop, domestic hot water, desuperheater hot water) and two reversing valves. There is also a solenoid valve on the air coil. The installation is quite a hack job - PVC pipe mated directly to swivel connections, no PT ports. Another system, a split, shares the desuper tank (only one tank, of course) Both desupers and the package unit main domestic coax are piped to the same tank, all without check valves, of course... Main complaint - very low cooling, confirmed by 5 degree air side temperature split. Superheat 20-ish, Subcool 6-ish. We added a bit of refrigerant, but head pressure of 350 is well in excess of what we expect for water side conditions, so reluctant to add any more. Waterside consists of open loop with reinjection - EWT 74, LWT 82, though without PT ports no way to calculate flow or heat rejected. Searches online and calls to the company (number no longer in service, website 404) turned up no service or troubleshooting info. No schematic as to refrigerant path, sequence of operation, etc. We are somewhat suspicious of the inner reversing valve, wondering if it is hung up midway, backing refrigerant up or diverting it somehow, but that hunch is weakly held. Replacing that valve would be an ordeal, costing the client $1500+. Not being part-swappers, we are very reluctant to go down that road with decision support. Interestingly (to me anyway) searches online revealed my own blog posts here back in 2008...the geo world is small indeed. Any helps, tips, docs, links greatly appreciated. Curt
http://www.northernheatpump.com/documents/NHP 2008 US Product Catalog.pdf This was from a greenbuildingtalk thread. http://www.greenbuildingtalk.com/Forums/tabid/53/aff/13/aft/45978/afv/topic/Default.aspx
