MIS called me, as I'm a Bulidings and grounds TECH. Limited A/C knowledge.
He said the server rooom was getting hot. Servers put out some heat.
There are 2 units in the room. A Reem and a Rudd unit. The room has no fresh air only room air. Each unit takes room air and for the bottom which blows over the evaporation coils. The condensers are on the roof 2 of them. The filters at bottom of the room units were very clean. I went to the roof and found on the Reem unit a frozen Suction line. As well as a frozen Evapoator coil. I live in syracuse NY. Where the nights get cold. I remember a Contracor many years ago when it was 29 degrees out went to the roof units and overrided something electronically. Because the same thing happened.Low refrigerant will do this i think. 410A
A/C frozen Suction line
hvac
Related Solutions
You may be looking at the problem backwards, the freezing lines could be a symptom of the problem not the cause. Start by looking for blockages in the system that would cause lower air flow / heat exchange.
- Dirty filters.
- Clogged ducts.
- Closed dampers.
- Closed/Blocked vent covers.
- Dirty coils.
Basically if the system cannot exchange the heat/cold, it will not function properly and could lead to over heating/cooling.
Frozen lines could also be caused by high or low levels of refrigerant, so you'll want to get a service person out to check the refrigerant levels.
Here is a really good image to visualize how it works.
Because of the need to capture the refrigerant and licenses to get the refrigerant in most places, this typically isn't a DIY job. The fact that the outside unit is running and air is blowing inside suggests that it's not a problem with the thermostat. Check the breaker, air filters, and any other easy to access components for obvious problems. Beyond that, there are a lot of possible issues:
- Compressor has failed
- No refrigerant or not enough
- Controller has failed or wiring has become disconnected
- Inside coils have frozen over
Since the first two are the most likely and either will need a professional to repair, you may as well get one out to diagnose the problem for you.
Best Answer
Frozen suction line and evaporator coils can be caused by a few different items. But basically the A/C unit is making more cooling than the air flow can dissipate. Dirty filters is the first place to look. They will restrict air flow. Not enough air flow means inability to dissipate cooling to the room, means freeze-up. If the filters are good, look at the coil itself. Is it dirty? Shut the system down, defrost the coil then you can inspect it. If it is dirty, you have to clean it. dirt on the coil face will restrict air flow. Lack of air flow can mean freeze-up. Now check to make sure the blower wheel is clean. A dirty blower wheel cannot mover air like it should. If it is dirty, you have to pull that blower wheel and clean it. Not very much dirt on those fins can reduce the efficiency of the wheel a lot. Not enough air movement across the coil means freezing. Now think about it this way, you want to direct as much warm air across those coils as you possibly can. Is there any way to augment the flow of the warm air in the room across those cooling coils? If the room thermostat is calling for cooling those compressors are going to run. When they run they are going to produce a certain amount of cooling regardless of other conditions in the room. If you can't dissipate that cooling off the coils they will over cool and freeze. With a frozen coil, not enough air flow across the coil is 95% of the time the problem. Either move more air or shut the units for a short period of time to let the warm air catch up. This is a good start. Good Luck.