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coolrunnings1
05-07-2009, 04:19 PM
Hello

I have a 4 door dumper fridge it is not cooling.

It is a commercial fridge stainless steel Not that that matters much.

Anyway the complaint is it is not cooling, There is some ice build up on the back of the evaporator.

I have checked the pressures and they seem to be correct.

The compressor is very very hot and also is the condenser (75 degrees C).

So i have checked the relay.. It clicks and there is a blue spark when it starts.

The compressor starts as well. However within a second there is a second spark inside the relay....

I am thinking that the relay is faulty and will need changing

any thoughts please let me know... Relay or capasitor?

But the Compressor is working BUT HOT

Gary
05-07-2009, 04:38 PM
Evap air in temp
Evap air out temp
Low side pressure/saturated suction temp
Suction line temp at TXV bulb

Cond air in temp
Cond air out temp
High side pressure/saturated condensing temp
Liquid line temp at receiver/condenser outlet

coolrunnings1
05-07-2009, 04:43 PM
All I can say is that the evap temp in general is 8 degrees C...

The con temp is 75 Degrees C.

On this fridge I can only check pressures via a service valve on the top of the comp...

Dont have valves on high side and the low side.

Not a very big comp

Gary
05-07-2009, 04:55 PM
We need as many of these temps/pressures as you can get.

Yuri B.
05-07-2009, 04:58 PM
If relay that "sparks", it is evidently not good already.
The burning relay, however, may be only a consequence of another fault.
Maybe RUn capacitor bad (if such there is), or the compressor is "braking" during runtime, both making the start relay constantly switching on and off the START capacitor.
Fridge is most probably heavily overloaded.

tonyelian
05-07-2009, 07:29 PM
hi
size of compressor and ***** is it original
were did u measure 75degree if after the drier u must check if the condenser is clean if so air in &air out.
check compresser amp if its high it makes relay energises stsrt windings that what making relay sparks &comp hot

coolrunnings1
05-07-2009, 10:42 PM
Will have to check these out.

I will have to check the relay and cap....

The temp I have taken is on the condenser its self.

What I did notice was when I put the gage on the only service valve which is on the top of the comp some oil smelling stuff came out..

Could this be moisture etc......

Peter_1
05-07-2009, 11:02 PM
What I did notice was when I put the gage on the only service valve which is on the top of the comp some oil smelling stuff came out..
Could this be moisture etc......

I think the oil from the cap entered the refrigeration circuit via the leads and came this way into the circuit and contaminated the refrigerant.
This contamination now blocks the starting relay.

monkey spanners
05-07-2009, 11:58 PM
I think the oil from the cap entered the refrigeration circuit and came this way into the circuit and contaminated the refrigerant.
This contamination now blocks the starting relay


I hate it when this happens :( Much better with three phase stuff imho.

coolrunnings1
06-07-2009, 09:40 AM
So if I replace the cap would this help also changing the relay.

???????

coolrunnings1
06-07-2009, 10:58 AM
So if I replace the cap would this help also changing the relay.

???????

Comp would only be a 1 phase also

monkey spanners
06-07-2009, 11:39 AM
I'd want to have an amp probe/current meter on the live feed to the compressor to see how much current it is pulling, sparking could be klixon operating if compressor is pulling too much power. And to test capacitor with a meter also.

Could be faulty relay/capacitor stopping compressor from running properly or faulty compressor (partly siezed, or shunted windings) making relay chatter. Or a blockage making the compressor run with too high a discharge pressure.

coolrunnings1
06-07-2009, 12:09 PM
I'd want to have an amp probe/current meter on the live feed to the compressor to see how much current it is pulling, sparking could be klixon operating if compressor is pulling too much power. And to test capacitor with a meter also.

Could be faulty relay/capacitor stopping compressor from running properly or faulty compressor (partly siezed, or shunted windings) making relay chatter. Or a blockage making the compressor run with too high a discharge pressure.


That was next thing to try. However was going to do the job today and just found out that my bro got house broke into this morn DOH!!! Crime here in Tenerife is on the rise.

Anyway will try these prob tomorrow now any other thoughts are welcome

lowcool
07-07-2009, 04:29 AM
all relays were black in the old days hence no arcing was ever seen