反(fan)饋(kui)(kui)桿(gan)(gan)故障。長期運行中反(fan)饋(kui)(kui)桿(gan)(gan)緊固(gu)螺母逐漸松動(dong)(dong)甚(shen)至(zhi)脫(tuo)(tuo)(tuo)落(luo)(luo)，造(zao)成反(fan)饋(kui)(kui)桿(gan)(gan)松動(dong)(dong)、歪斜、與固(gu)定(ding)件卡碰(peng)、脫(tuo)(tuo)(tuo)落(luo)(luo)。使調節(jie)閥動(dong)(dong)作遲緩，波動(dong)(dong)頻繁，調節(jie)閥限位甚(shen)至(zhi)失去控(kong)(kong)制。反(fan)饋(kui)(kui)板上的限位彈簧脫(tuo)(tuo)(tuo)落(luo)(luo)，或(huo)反(fan)饋(kui)(kui)桿(gan)(gan)從(cong)中脫(tuo)(tuo)(tuo)出(chu)，造(zao)成反(fan)饋(kui)(kui)桿(gan)(gan)與反(fan)饋(kui)(kui)板接觸不良(liang)，產(chan)生(sheng)(sheng)滯后(hou)，造(zao)成調節(jie)閥動(dong)(dong)作頻繁。使被控(kong)(kong)參數難以穩定(ding)特別在調節(jie)閥動(dong)(dong)作要求準確的溫度控(kong)(kong)制中產(chan)生(sheng)(sheng)較大影響。

固定螺(luo)(luo)母(mu)松(song)(song)動(dong)(dong)。定位(wei)(wei)(wei)器(qi)固定螺(luo)(luo)母(mu)安裝(zhuang)不(bu)牢產(chan)生(sheng)松(song)(song)動(dong)(dong)，造(zao)成定位(wei)(wei)(wei)器(qi)歪斜，影(ying)響(xiang)反饋(kui)桿動(dong)(dong)作，造(zao)成卡碰現(xian)(xian)象。使(shi)(shi)調(diao)節閥動(dong)(dong)作不(bu)穩定，產(chan)生(sheng)限(xian)位(wei)(wei)(wei)等(deng)現(xian)(xian)象。定位(wei)(wei)(wei)器(qi)中各種(zhong)彈(dan)簧的緊(jin)固螺(luo)(luo)絲在震動(dong)(dong)環境(jing)下松(song)(song)動(dong)(dong)，改變(bian)了彈(dan)簧的預緊(jin)量，影(ying)響(xiang)彈(dan)簧的張力和狀態。使(shi)(shi)定位(wei)(wei)(wei)器(qi)的零點量程發生(sheng)改變(bian)，定位(wei)(wei)(wei)器(qi)不(bu)線性(xing)，致使(shi)(shi)調(diao)節閥不(bu)能全(quan)開全(quan)關(guan)，調(diao)節閥動(dong)(dong)作不(bu)線性(xing)。磁鐵位(wei)(wei)(wei)置發生(sheng)變(bian)化。