Hi, our apartment building is having hot water issues. Some apartments including mine have 50 degree water coming out of the hot side. I replaced the recirculating pump and the return temp is still 50. My question is do you think that the pipes being pex in a crawlspace under the apartments cool to 50 with the pump going or should I look for a bad mixing valve somewhere? It's probably about 0-5 degrees outside but I know the pump is working. It's the same temperature in the crawlspace as it is outside. Any suggestions?