Frick blowdown

[NH3ISFORME]

I've blown down our machines before but this one hasn't run for a while. The shaft seal needed to be changed, so when I equalized the machine at the bypass suction check valve, I noticed water in the sight glass! At that point I tried to blow down the compressor but the coalescing section and the oil filter housing iced up. Obviously there is liquid in these areas. When I got my pressures to 8 psig I began draining oil. My intention is to drain all the oil to rid the machine of water as much as possible. I know now that the liquid ammonia in the frosted areas is not going to make oil draining easy for those areas. Any suggestions?

[Segei]

I've blown down our machines before but this one hasn't run for a while. The shaft seal needed to be changed, so when I equalized the machine at the bypass suction check valve, I noticed water in the sight glass! At that point I tried to blow down the compressor but the coalescing section and the oil filter housing iced up. Obviously there is liquid in these areas. When I got my pressures to 8 psig I began draining oil. My intention is to drain all the oil to rid the machine of water as much as possible. I know now that the liquid ammonia in the frosted areas is not going to make oil draining easy for those areas. Any suggestions?

Probably it isn't water in the sight glass. This is liquid ammonia due to leaking discharge check valve. The best way to evaporate this liquid is to run compressor. Another way to close discharge valve, open bypass of suction check valve and it takes time to evaporate liquid ammonia. Keep oil heater on and use external air heaters to speed up evaporation.

[lowtempman]

Probably it isn't water in the sight glass. This is liquid ammonia due to leaking discharge check valve. The best way to evaporate this liquid is to run compressor. Another way to close discharge valve, open bypass of suction check valve and it takes time to evaporate liquid ammonia. Keep oil heater on and use external air heaters to speed up evaporation.

I agree with Segel that it probably is not water. If water had gotten into the system it would end up in the low side; the low presure receiver, shell and tube evaporator, or whatever the low side consists of. But there is a remote chance it could be water under very unusual circumstances, but that is a subject for another post for now. In any event follow Segel's advice and try to evaporate the ammonia out of the Frick compressor unit. This is the way to proceed regardless whether there is water or not.

If it turns out to be water try, of course, to determine where it got into the system. And it might be advisable to check the composition of the ammomnia in the low side if you suspect water. A small amount of water in ammonia is tolerable but the more water the less capacity, the warmer the evap temp, and the more power required.

[ammonia tec]

water /air will b up in the cond. raiseing head. take super heat on liq return on cond.if water then i would set purge time longer and tighten and inspect all low side valves and bolts

[ammonia tec]

more likely its sucking it in on low side.

[scuba]

What type of oil cooling is used on these machines liquid injection or thermosyphon. Have you checked the check valves on these machines for failures?