Frozen Suction and Compressor

How is the flow across the evaporator?

I would check all the usual things....and fix the problem....If you can't do that, then call somebody who can.....We can't troubleshoot the system from here...well maybe we could if you would supply all the necessary information and readings, but I sense that's not likely...

Start with the TEX - dump it.

Is it short-cycling?

What is a permutor?

Sorry, I'm not a native English speaker and the word didn't came to my mind at that moment, it is an heat exchanger (fluid-to-water).

I'll be at the site again tomorrow so I will be able to provide any details you may see necessary. I'll make sure to provide evaporation and condensing temperatures, subcooling and superheating values and pressures before and after evaporator.

Any other information you think may be useful just ask and I'll try to provide it tomorrow.

By TEX means thermic expansion valve?

Many thanks in advance for your time and effort.

Yes, TEX = Thermostatic Expansion Valve.

If it is winter where you are and you are extracting heat from geothermal water to heat the home/factory, 3 possibilities come to mind.

1. Inadequate depth in the earth for the source water to be at deep earth equilibrium.

2. Low snow cover so the shallow source water is ready to freeze as soon as you extract a little heat.

3. Inadequate velocity of water circulation pump so water stays by the fins too long and freezes fast.

CURE

Deeper GTW source

Foam insulation for winter over the bed.

Higher pump velocity or volume capacity, perhaps right on the fins with a spreader

You could start with stated requirements by the manufacturer for the system to function properly...and take readings on what you have in actual location...If you are trying to operate the system outside the necessary requirements, then there will be a modification needed....

Please describe the outcome of the telephone discussions that have taken place with the equipment manufacturer on this topic.

Make certain the system is correctly charged with R407c, by consultation with the Original Equipment Manufacturer, and get back with us, and let us know if you survived the cold.

Sounds like the water is not circulating....check pump and refrigerant pressures at start up after complete thaw....

Exactly what is freezing?Is it the circulating water system,or the Freon system?

From what I can determine from the information given,it is the Freon side of the system that is freezing,on the suction side only?

Is it freezing only on the outside of the piping,or internally as well?

Are you using the heating mode or the cooling mode?

It is normal for the suction side to be cool,even sweating,in high humidity environment,but the pressure side should be hot,if all systems are doing their job.

The TXV is on the pressure side, after the condenser,so there should only be liquid Freon there for the TXV to regulate.

If there is not quite enough pressure on the Freon side,the evaporator will run very cold, due to the reduced pressure,and consequently, the temperature, of the Freon.

That would be my first guess at the problem with the limited information provided.

If the evaporator is partially clogged,you will be sending liquid Freon to the suction side of the compressor,which you will be able to hear as a rattling sound,but it will eventually destroy the compressor valves,unless it is a scroll type compressor.

Not much heat will be picked up by the Freon,and the suction side will not be very cold.

Check your system pressures, on both hi and lo sides,as well as the Super heat and Sub cooling temperatures and measure the in/out temperatures of the water on both sides of the evaporator and condenser.

This,combined with basic HVAC principles will reveal the problem.

Good luck!

If by frozen you mean ice has formed on these components, it tells me the saturaged evaporator temperature is at of below 32 deg F, and the dew point of the air surrounding these components is at or above 32 deg F. What's happening on the outside of the equipment should not affect it's performance if it's designed to operated unders such conditions.

If it's not no flow across the evaporator [slow flow, dirty heat exchanger tubes, wouldn't freeze it up that fast] you are low on R407c, if it's not new the leak will drop the level and it won't work at all and pump air into the system when you check it again.

Sounds like the evaporator fan is not working....

Check the Suction and discharge pressure and compare it with the O& M manual. Refrigerant is mixture and check for temperature glide aspect. Check leak for refrigerant and the operation of heat exchanger fans.

Hello. I am late on this post. You may have already found your solution.

However i see English is not your native tongue.

Engineer speak can be very difficult for those where English is not their mother tongue.

I will probably catch some hell for this, but let me try some Plain English.

Frost on the low pressure side of an AC unit is common. It depends on the surrounding ambient air temperature and humidity etc.

However your description can also indicate too low of a pressure on the low side.

As explained in other posts, to diagnose the problem, a pressure reading is where to start.

If the pressure on the low side is too low, then you will want to check the high side pressure .

If both sides are low, the initial charge of refrigerant was not sufficient or has leaked off.

If the low side is low and the high side high, you most likely have a stuck expansion valve or a plugged filter / screen.

Either way , "if" your compressor's lubricating oil circulates with the refrigerant the compressor is being starved of lubricating oil and may be damaged.

If the system must be opened to repair, i suggest you pay close attention to any material caught by the filter. That can explain if the compressor is damaged or not.

If compressor material is found circulating in the system, all system parts have to be flushed / cleaned or replaced to prevent repeat failures.

Hope this helps.