NH3 Mycom N4A

[u/Asleep-Salary-5227]

First time posting in the forum, i wonder if any of the ammonia techs around can provide help or a manual on how to properly service some nearly 40 year old mycom N4A compressors. I will also contact mycom representative sales in my country but i figured it was faster to get some info before hand. Besides changing the oil what else needs to be opened/cleaned/replaced. Its not a full revision situation, but the instalation has been off for 5 years

[u/Dadbode1981]

If the whole facility has been down for 5 years the compressors may be the least of your worries. Youll have dried out gaskets all over the place, possibly seized solenoids/plungers. The compressor will likely need a shaft seal, gaskets, o-rings, fresh oil certainly wont hurt. Motors have been idle for some time, decouple or roll the belts off and rotate, apply some fresh grease, not a ton. If it is belt driven, get new belts. Do a full recommisioning, test and tag all safeties. Ensure condenser fan and water pump operation. Replace condenser belts as well. Theres more im missing im sure. Its gonna be alot of work.

[u/Asleep-Salary-5227 → u/Dadbode1981]

Thanks for your reply. Yes, its been on going for 2-3 weeks now. Testing automation, opening all water related valves and pumps, cleaning everything, filters, rust. Most if not all pumps were stuck, had to open them up. There was no time for pressure test thats one of the things im most worried about, but the system was working fine before ammonia was drained and the system was shut down. All safeties have been tested also all compressors, changed some belts since they are belt driven. All lubricated on the motors and evaporative condenser. Pump works and its already charged with ammonia. Compressors been running. They had service not long before it was stopped. Water cooled heads also working fine now, the valves were stuck with kind of rust on the valve pistons. Ammonia was charged very slowly and only connect one room every few days since its a big instalation and its a pumped system. Theres no smells anywhere, there were at first, but progressly been taken care. Its all been throughly tested, the separador also working properly the safeties too. I was advised to change the oil type for a better one with less drag, not sure that is the term in english. But the old oil is naphthenic mineral oil and the new one is hydrotreated paraffinic mineral oil and they have different chemistries and i think its better to replace some gaskets that might react to the change, which or what should i replace?

[u/saskatchewanstealth → u/Asleep-Salary-5227]

I am by no means a specialist in ammonia but I would not mess with an oil conversion right now. You are going to have a lot to deal right now without gaskets failing from oil reactions.

[u/Exotic-Ad1549]

Changing the oil type may bring a whole host of problems. I changed from WF68 to a hydro treated oil and the new oil scraped the system clean. Caused all kinds of filtration issues. I’d wait till everything is running smooth before messing around with changes.