Post by cablehack on Jan 6, 2019 1:53:09 GMT
It has been a hot summer here for the past few weeks, with ambient room temps of about 28 to 34C, several days in a row sometimes.
As I've mentioned here monitortop.freeforums.net/thread/1521/motor-overload-protector-function-test?page=2 I have a timer connected to the CA-2 so that if the motor runs continuously for 30 mins, the supply is shut off. Then, after another 30mins to allow the motor to cool down, it restarts.
On the 17th December, the 30 min timer tripped, and there was a stall on startup so I purged the machine. Nothing unusual about that with the warm weather and there was some NCG's present.
Then, on 2nd January, it timed out again. Kitchen temp was 30C. This seemed odd because it shouldn't need purging so soon. Indeed, there was no sign of NCG with all the condenser warm, no rattle, and the power consumption was normal. I purged it again anyway just to narrow down the 'problem'.
Yesterday, on the 5th January, I happened to be away from home all day, but I had a friend staying at my house. Kitchen temp got to 34C. He told me that "the warning light under the fridge came on" in the morning (i.e. it timed out) but later on it went off and all was normal. So, the automatic reset worked. By the evening, after a cool change came through, room temp was 26C and it was like nothing ever happened.
It appears that once a certain ambient temperature is reached, the run time exponentially increases. From the normal 3-5 mins, it can suddenly become more than 30 mins. There is no actual fault with the fridge as such, no NCG or blocked evaporator. My conclusion is that because a capillary tube is used, there comes a point when the cooling demand is higher than normal, where the tube sizing is such that sufficient refrigerant cannot flow. Of course with the float valve, the valve simply opens more to admit more liquid. It is a known limitation of capillary tubes that they work best under one set of conditions, and I'd say that what I've experienced is proof of this.
Having said that, despite the unusually long run time, the cabinet temperature was maintained. Also, it's only above 30C this phenomenon may occur - which is for a very short time of the year. In future I will be less likely to over react and purge the machine when this happens.
As I've mentioned here monitortop.freeforums.net/thread/1521/motor-overload-protector-function-test?page=2 I have a timer connected to the CA-2 so that if the motor runs continuously for 30 mins, the supply is shut off. Then, after another 30mins to allow the motor to cool down, it restarts.
On the 17th December, the 30 min timer tripped, and there was a stall on startup so I purged the machine. Nothing unusual about that with the warm weather and there was some NCG's present.
Then, on 2nd January, it timed out again. Kitchen temp was 30C. This seemed odd because it shouldn't need purging so soon. Indeed, there was no sign of NCG with all the condenser warm, no rattle, and the power consumption was normal. I purged it again anyway just to narrow down the 'problem'.
Yesterday, on the 5th January, I happened to be away from home all day, but I had a friend staying at my house. Kitchen temp got to 34C. He told me that "the warning light under the fridge came on" in the morning (i.e. it timed out) but later on it went off and all was normal. So, the automatic reset worked. By the evening, after a cool change came through, room temp was 26C and it was like nothing ever happened.
It appears that once a certain ambient temperature is reached, the run time exponentially increases. From the normal 3-5 mins, it can suddenly become more than 30 mins. There is no actual fault with the fridge as such, no NCG or blocked evaporator. My conclusion is that because a capillary tube is used, there comes a point when the cooling demand is higher than normal, where the tube sizing is such that sufficient refrigerant cannot flow. Of course with the float valve, the valve simply opens more to admit more liquid. It is a known limitation of capillary tubes that they work best under one set of conditions, and I'd say that what I've experienced is proof of this.
Having said that, despite the unusually long run time, the cabinet temperature was maintained. Also, it's only above 30C this phenomenon may occur - which is for a very short time of the year. In future I will be less likely to over react and purge the machine when this happens.
