External walk in freezer issue help compressor

[Gtown]

Hi

its my first time posting on here or in any forum so apologies if im in the wrong thread or doing anyhting wrong if you could point me in the right direction it would be greatly appreciated

a bit of background im fully qualfied electrican registered with napit and just need some clarification from someone more knowledgable than me on this regarding compressors

i recently had an call out to a repeat customer to look at a single phase external walk in freezer situated at the back of a resturant that had been tripping im not an refrigeration engineer which i told the customer but he wanted me to check the basics before calling out a specialist. when i arrived at the job the following day it was all working and the customer said they had been resetting the breaker everytime it tripped and it just stayed on after a while. They said it started tripping when the door was opened this had a contact switch for the internal light. upon checking the light fitting there was frozen water inside the fitting im guessing that in a hot day (walk in freezer outside) there may have been condensation forming that had made its way into the light fitting freexing and when it heated up the water melting hence causing the tripping the light fitting in question was just a cheap bulkhead with a bc E27 led lamp in it, (if there are any other reasons why condensation would be forming please advise)

i spoke to my whoesaler (cef) for something suitable and they provided an ip65 led bulkhead that was suitable down to -25 that was suitable

i replaced the old light fitting with the new one (siliconing the small rear entrance hole aswel as the two screw holes to seal) and powered back up after testing.

the compressor took a little while to kick in once the door was shut and from what i read on the manual of the unit it goes through a few checks before powering up.

fast forward three weeks later with no issues and i had a call from the customer saying the freezer had tripped at the breaker, unfortunately i was on holday and couldnt attend but was happy to do so once i returned.

uopn returning from holiday i contacted the customer to see if they managed to get the freezer sorted or if they needed any further assisance i was told that the company that came out had said the light fitting wasnt suitable for the freezer, condensation had got into the new light fitting which in turn had damaged the compressor which also needed replacing (which the company then proceeded to replace)

Please correct me if im wrong but i cant see how the short circuit of water in the light fitting could damage the compressor once the power had tripped, unless the breaker has been repeatedly turned on and off again by the customer due to constant tripping in a short space of time which in turn has led to the over heating/ damage of the compressor,

im not overly familiar with compressors but i was always taught they shouldnt be switched on and off frequently, my other thought was if the compressor was starting to need some maintenance work and with the freezer being situated outside on sunny days could it be struggling to maintain temperature resulting in condensation?

since the other company went to the call out my orginal light fitting has been disposed of so i cant check it for defects (i know condensation shouldnt have been able to get inside the fitting in the first place which is a concern which i will be looking into further via cef)

I am looking at compensating the customer to try make thins right but the cost of replacing these was £2000 (alot more for than my original bill i charged for replacing a light fitting) and id just like to know all the facts before i go down this route, if the fail of the compressor could be my fault? i admit water getting into the fitting would be attributed to me even though the fitting (on the spec sheet at least) should have been suitable for the location

any help would be greatly appreciated on this or if any one has been in this situation before as its a first time for me

 

[ProDave]

i was told that the company that came out had said the light fitting wasnt suitable for the freezer, condensation had got into the new light fitting which in turn had damaged the compressor which also needed replacing (which the company then proceeded to replace)

That is high up the BS scale, water in the light fitting won't affect the compressor. your fitting seems a lot more suitable than an E27 light bulb.

You don't need to compensate anyone, just move on. it might well be the compress was the issue all along but that will require an F gas engineer to de gas it, replace the compressor and re gas it.

 

[Marvo]

Hi

its my first time posting on here or in any forum so apologies if im in the wrong thread or doing anyhting wrong if you could point me in the right direction it would be greatly appreciated

a bit of background im fully qualfied electrican registered with napit and just need some clarification from someone more knowledgable than me on this regarding compressors

i recently had an call out to a repeat customer to look at a single phase external walk in freezer situated at the back of a resturant that had been tripping im not an refrigeration engineer which i told the customer but he wanted me to check the basics before calling out a specialist. when i arrived at the job the following day it was all working and the customer said they had been resetting the breaker everytime it tripped and it just stayed on after a while. They said it started tripping when the door was opened this had a contact switch for the internal light. upon checking the light fitting there was frozen water inside the fitting im guessing that in a hot day (walk in freezer outside) there may have been condensation forming that had made its way into the light fitting freexing and when it heated up the water melting hence causing the tripping the light fitting in question was just a cheap bulkhead with a bc E27 led lamp in it, (if there are any other reasons why condensation would be forming please advise)

I'm assuming it was an RCD tripping? Did you do an insulation test on the light? Did you insulation test any other components such as the defrost elements and the compressor?

Even on a hot day the internal temperature of the freezer room will never get even close to zero degrees C, usually around -14 would be the warmest so there won't be condensation as such.

The common cause of condensation inside a freezer room is if the defrost cycle is set too long and/or if the defrost cycle abort thermostat is inoperative.

When defrost starts the refrigeration system should 'pump down' and the compressor will turn off. The defrost elements inside and/or underneath the evaporator coil will heat and raise the evap coil temp above zero celsius, the ice that's built up on it will melt and run down the drain. Usually there's a small thermostat inside the evaporator coil box that will abort the defrost when the temperature inside the evaporator box gets to maybe 10 or so degrees C. Sometimes there is no abort thermostat and the defrost cycle just terminates after a preset time.

If the defrost cycle runs too long the evap coil and the drain pan get too hot which causes any remaining water on/in them to turn to steam and condense on the roof of the room and the light fitting which is much cooler. This causes the inside of the room to drip like an equatorial rainforrest, ice stalactites can form on the roof and even stalagmites on the floor. It can also cause water pooling in the light fitting if its IP rating is poor.

The evaporator fans also usually have a delayed start for a preset time after a defrost cycle and the compressor restart to prevent blowing the hot humid air around the evaporator coil into the room for this very same reason.

i spoke to my whoesaler (cef) for something suitable and they provided an ip65 led bulkhead that was suitable down to -25 that was suitable

i replaced the old light fitting with the new one (siliconing the small rear entrance hole aswel as the two screw holes to seal) and powered back up after testing.

the compressor took a little while to kick in once the door was shut and from what i read on the manual of the unit it goes through a few checks before powering up.

If you installed an IP65 fitting that was rated to -25C and sealed any cable entries with silicone then it was appropriate for the application.

Refrigeration systems in general often have a delay of 2 or 3 mins between power up and compressor start. This is to allow the refrigeration system to equalise and prevent unnecessarily high mechanical stress and start currents caused by the compressor trying to start with a high pressure differential across it.

fast forward three weeks later with no issues and i had a call from the customer saying the freezer had tripped at the breaker, unfortunately i was on holday and couldnt attend but was happy to do so once i returned.

uopn returning from holiday i contacted the customer to see if they managed to get the freezer sorted or if they needed any further assisance i was told that the company that came out had said the light fitting wasnt suitable for the freezer, condensation had got into the new light fitting which in turn had damaged the compressor which also needed replacing (which the company then proceeded to replace)

Please correct me if im wrong but i cant see how the short circuit of water in the light fitting could damage the compressor once the power had tripped, unless the breaker has been repeatedly turned on and off again by the customer due to constant tripping in a short space of time which in turn has led to the over heating/ damage of the compressor,

As I mentioned above if it's correctly designed the compressor will be protected against damage by short cycling caused by rapid power fail and restore.

Firstly request the customer put in writing any accusations of poor workmanship or inappropriate materials. Then go to your supplier and ask then for a spec sheet on the light fitting and show the customer, tell them the other contractor is incorrect in his accusation and you're happy to prove it.

im not overly familiar with compressors but i was always taught they shouldnt be switched on and off frequently, my other thought was if the compressor was starting to need some maintenance work and with the freezer being situated outside on sunny days could it be struggling to maintain temperature resulting in condensation?

Again it should be protected against short cycling, if not it was either poorly designed from new or some butcher has reconfigured it to bypass the protection at a later date.

And again, apart from the defrost cycle being too long, if the freezer ever got warm enough inside to allow condensation to get inside the light fitting then the stock inside the freezer would have defrosted and spoiled.

since the other company went to the call out my orginal light fitting has been disposed of so i cant check it for defects (i know condensation shouldnt have been able to get inside the fitting in the first place which is a concern which i will be looking into further via cef)

I am looking at compensating the customer to try make thins right but the cost of replacing these was £2000 (alot more for than my original bill i charged for replacing a light fitting) and id just like to know all the facts before i go down this route, if the fail of the compressor could be my fault? i admit water getting into the fitting would be attributed to me even though the fitting (on the spec sheet at least) should have been suitable for the location

any help would be greatly appreciated on this or if any one has been in this situation before as its a first time for me

I'm not going to advise you on how you should deal with your customer but I would say that I personally (or my insurance company for that matter) wouldn't entertain any damages claim unless there's good evidence I had caused it and another contractors accusation alone would fall far short of the good evidence benchmark. As an absolute minimum in this type of case I would require I take posession of the failed compressor which I would have the agents perform a post mortem report on and also the old light fitting to have it inspected and even replaced under warranty if it was defective and not fit for purpose.

I would also say that it's not unheard of for less scrupulous contractors to encourage customers to persue previous contractors for damages and offer to bias their report toward making them liable. I'm not sure how it works in the UK but maybe you could approach NAPIT for assistance and advice? Also I'm assuming you've got liability insurance so maybe now is a good time to phone their helpline or your broker for some advce also.

 

[Gtown]

That is high up the BS scale, water in the light fitting won't affect the compressor. your fitting seems a lot more suitable than an E27 light bulb.

You don't need to compensate anyone, just move on. it might well be the compress was the issue all along but that will require an F gas engineer to de gas it, replace the compressor and re gas it.

Hi

That is high up the BS scale, water in the light fitting won't affect the compressor. your fitting seems a lot more suitable than an E27 light bulb.

You don't need to compensate anyone, just move on. it might well be the compress was the issue all along but that will require an F gas engineer to de gas it, replace the compressor and re gas it

That is high up the BS scale, water in the light fitting won't affect the compressor. your fitting seems a lot more suitable than an E27 light bulb.

You don't need to compensate anyone, just move on. it might well be the compress was the issue all along but that will require an F gas engineer to de gas it, replace the compressor and re gas it.

thank you for taking the time on an evening to message back it's massively appreciated

 

[Gtown]

I'm assuming it was an RCD tripping? Did you do an insulation test on the light? Did you insulation test any other components such as the defrost elements and the compressor?

Even on a hot day the internal temperature of the freezer room will never get even close to zero degrees C, usually around -14 would be the warmest so there won't be condensation as such.

The common cause of condensation inside a freezer room is if the defrost cycle is set too long and/or if the defrost cycle abort thermostat is inoperative.

When defrost starts the refrigeration system should 'pump down' and the compressor will turn off. The defrost elements inside and/or underneath the evaporator coil will heat and raise the evap coil temp above zero celsius, the ice that's built up on it will melt and run down the drain. Usually there's a small thermostat inside the evaporator coil box that will abort the defrost when the temperature inside the evaporator box gets to maybe 10 or so degrees C. Sometimes there is no abort thermostat and the defrost cycle just terminates after a preset time.

If the defrost cycle runs too long the evap coil and the drain pan get too hot which causes any remaining water on/in them to turn to steam and condense on the roof of the room and the light fitting which is much cooler. This causes the inside of the room to drip like an equatorial rainforrest, ice stalactites can form on the roof and even stalagmites on the floor. It can also cause water pooling in the light fitting if its IP rating is poor.

The evaporator fans also usually have a delayed start for a preset time after a defrost cycle and the compressor restart to prevent blowing the hot humid air around the evaporator coil into the room for this very same reason.




If you installed an IP65 fitting that was rated to -25C and sealed any cable entries with silicone then it was appropriate for the application.

Refrigeration systems in general often have a delay of 2 or 3 mins between power up and compressor start. This is to allow the refrigeration system to equalise and prevent unnecessarily high mechanical stress and start currents caused by the compressor trying to start with a high pressure differential across it.





As I mentioned above if it's correctly designed the compressor will be protected against damage by short cycling caused by rapid power fail and restore.

Firstly request the customer put in writing any accusations of poor workmanship or inappropriate materials. Then go to your supplier and ask then for a spec sheet on the light fitting and show the customer, tell them the other contractor is incorrect in his accusation and you're happy to prove it.


Again it should be protected against short cycling, if not it was either poorly designed from new or some butcher has reconfigured it to bypass the protection at a later date.

And again, apart from the defrost cycle being too long, if the freezer ever got warm enough inside to allow condensation to get inside the light fitting then the stock inside the freezer would have defrosted and spoiled.



I'm not going to advise you on how you should deal with your customer but I would say that I personally (or my insurance company for that matter) wouldn't entertain any damages claim unless there's good evidence I had caused it and another contractors accusation alone would fall far short of the good evidence benchmark. As an absolute minimum in this type of case I would require I take posession of the failed compressor which I would have the agents perform a post mortem report on and also the old light fitting to have it inspected and even replaced under warranty if it was defective and not fit for purpose.

I would also say that it's not unheard of for less scrupulous contractors to encourage customers to persue previous contractors for damages and offer to bias their report toward making them liable. I'm not sure how it works in the UK but maybe you could approach NAPIT for assistance and advice? Also I'm assuming you've got liability insurance so maybe now is a good time to phone their helpline or your broker for some advce also.

Thank you for taking the time to message back to me and for the detailed response it's very educational and appreciated, I was told it was the Rcbo that was tripping originally but by the time I got to the job it was no longer tripping I imagine the condensation inside the fitting had refrozen, it is only a really small unit and I do remember seeing small pools of water on the ceiling when attending it could be due to the warmer days I attended and the sudden blast of hot air hitting the ceiling of the freezer like you mentioned tioned, I did carry out insulation test on wiring to the light which was fine aswel as the usual Rcbo trip time and ramps test which was ok in all honesty I didnt do an insulation test on any components as from what the customer said it tripped when the door was opened which had a contactor switch for the light fitting and with There being water in the light I presumed that was the fault, if I had thought the issue was with the compressor control I would have probably passed it onto a specialist contractor with me being a bit unsure, i do have insurances in place but i greatly appreciate your advice in the matter on how to deal with this, i did get the feeling the company who carried out the work may have replaced more than what is necessary and my gut feeling is that even if condensation had got into the light and tripped the Rcbo, getting rid of the water ingress would have sorted the issue, although water getting in the past fittings even after sealing makes me thing there could be. An underlying issue with that you explained maybe the defrost cycle running to long as it's something I wouldn't know to check, is there a method of knowing how long the defrost cycle should run if it doesn't have a thermostat?
One final question would I right in be thinking there should be a record of maintenance for these freezers as i have a feeling this was a second hand unit to begin with and requesting a copy of any maintenance records would further help my cause,

Again I can't thank your self and other individuals who have commented great to see there people out there willing to help

 

[Marvo]

Not sure about maintenance log requirements, I'm not UK based so I'm not familiar with your local codes of practice.

If there's no defrost cycle termination thermostat then setting the time duration of the defrost is trial and error.

Just a thought but water can ingress a light fitting by travelling through capillary action inside the cable itself between the outer sheath and the internal insulated conductors. Pretty rare but I have encountered it in the past. That said the fact they 'disposed of' the light fitting suggests to me their story is fabricated, as a contractor they would have known you woujld want to see the failed fitting that supposedly caused several thousand quids worth of damage.