Performed two system maintenance. Nanny/Mrs Beatriz let me in. Immediately notice return air filter rack in lower part of wall in foyer/front entry. Pulled out extremely dirty filter. Both systems have 4 inch high efficiency filters at return air plenum filter rack. So no need for 1 inch filters in walls. Replaced and dated filters 20x25x4 in south side main system thermostat and 16x25x4 in north side/master bedroom suite thermostat. Treated drain lines and insured no restrictions. During drain line/fittings inspection found 3/4 elbow/coupling not glued properly on one end where it ties into other system drain lines. Made courtesy repair and glued fitting properly and supported properly with plumbing strap.. and to exposed suction lines at air handlers by taping up existing Armaflex insulation properly. Also made courtesy repair to big air leak at front access of Goodman air handler where connection to return plenum is made. Recommend shut off valve and float switch on primary drai