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stalker
31-10-2006, 06:59 AM
I have air2water heat pump, the refrigerant is R410A. Time-to-time I have to deflate gas from radiators.
How to determine, is this gas air or R410A?
Diffusion of small quantities of the R410A through refrigerant-water brazed plate heat exchanger - is it possible? Is it normal?

Brian_UK
31-10-2006, 07:48 PM
It may be possible but to be honest I would expect a refrigerant leak to be consistent. If it is leaking then it will continue to leak until the refrigerant is gone.

You are more likely to have a small air leak on the water side. Check valve stems and the inlet side of the pump.

NoNickName
31-10-2006, 08:38 PM
If it was R410, then in the condenser you shall find a small amount of moisture, and the sight glass tending to turn to yellow, even if the pressure of R410 is significantly higher than the water.

Brian_UK
31-10-2006, 11:00 PM
If it was R410, then in the condenser you shall find a small amount of moisture, and the sight glass tending to turn to yellow, even if the pressure of R410 is significantly higher than the water.That's assuming that he a sight glass fitted NNN, this is ahome conversion I believe.:(

US Iceman
01-11-2006, 01:37 AM
stalker,

I would like to ask a question to just clear up a few things on your description.

If the heat pump is air/water, I'm assuming the radiators contain water for the heating. Is that right?

If that is correct, the gas you are bleeding out is probably air. This is fairly common in water systems. The air is coming out of the water as the water circulates. If the air is not bled out, the air causes the radiator to gas bind and loose heating.

After bleeding out the air, does the radiator start to work again?

refteach
01-11-2006, 02:06 AM
Correct Iceman, on large boilers they have deaerator tanks that remove air (oxygen) from the makeup water before it enters the boiler. The tank heats the water to just the boiling point and drives out the air, there is usually a bleed line that allows the air to escape. So with out a deaerator, the water that is put into his system deaerates itself as time goes on.

Argus
01-11-2006, 08:47 AM
You may be dragging air in through the vent pipe, also corrosion in the pipes will produce gassing, usually hydrogen mixture.
This is well known in water central heatring sysyems and chemical inhibitors are available to cure it.

refteach
01-11-2006, 02:24 PM
More than likely it is air or as argus said a hydrogen mixture. To check for sure, use a electronic refrigerant leak detector to check the gas as it is bleed out, if the leak detector shows a positive you have a refrigerant leak.

taz24
01-11-2006, 05:30 PM
I have air2water heat pump, the refrigerant is R410A. Time-to-time I have to deflate gas from radiators.
How to determine, is this gas air or R410A?
Diffusion of small quantities of the R410A through refrigerant-water brazed plate heat exchanger - is it possible? Is it normal?

Normal radiators do need bleeding from time to time so it is normal. I do not think you have a problem with gas leaking into the water because thee is not that much gas in your heat pump. If it was gas and the radiator side was sealed then you would over pressurise the systems and cause a failure on that side.
It sounds normal to me :)

Cheers taz.

stalker
02-11-2006, 10:43 AM
My system has no sight glass.

Yes, bleeding radiators is normal, but it seems that the radiators need more bleeding than previous times I fill system with water and have no refrigerant2water heat exchanger in the system yet. May be it just seems..

I have no electronic refrigerant leak detector. Probably R410A doesn't smell?

What amont of R410A gas in normal pressure and normal temperature has the ordinary HVAC system? Not small amount I think.

The amont of the bleeding gas (air or air and R410A mixture) isn't big - the system has pressure change compensation tank and the pressure doesn't drop when bleeding.

Brian_UK
02-11-2006, 10:16 PM
My system has no sight glass.

Yes, bleeding radiators is normal, but it seems that the radiators need more bleeding than previous times I fill system with water and have no refrigerant2water heat exchanger in the system yet. May be it just seems..
...............................If you do NOT have a heat exchanger in line yet then how do you expect the refrigerant to get into the water side ? :confused:

Argus
02-11-2006, 10:32 PM
.

Time to call in an expert.

.

Brian_UK
02-11-2006, 11:31 PM
.

Time to call in an expert.

.Oh, that was a long, long time ago :D :(

stalker
03-11-2006, 10:22 AM
If you do NOT have a heat exchanger in line yet then how do you expect the refrigerant to get into the water side ? :confused:

Sry, my English isn't the best one:
When I HAD no *****2water heat exchanger in the system yet. I had electrical heater and solid fuel boiler and have them still as reserv heaters in the system, because heat pump doesn't work, when outside temperature is too low.

I hoped, you are experts who you are in this phorum..

taz24
03-11-2006, 06:32 PM
My system has no sight glass.

leak detector. Probably R410A doesn't smell?

What amont of R410A gas in normal pressure and normal temperature has the ordinary HVAC system? Not small amount I think.

The amont of the bleeding gas (air or air and R410A mixture) isn't big - the system has pressure change compensation tank and the pressure doesn't drop when bleeding.


Refrigerant does not smell, oil in it does but you will not smell it in your water. I doubt you have a leak to the water.
I do not know what size your heat pump is but I do not not think it would hold much more than 1 or 2 kg of refrigerant.

taz.

Rfcont
03-11-2006, 07:06 PM
I think there is probability leak through heatexchanger and it higher than in systems with R22 because
systems on R410a have higher work pressure
Unfortunately
If so then dayafterday you chiller will stop with failure "low pressure" or something in this sort
If no....all good;)

Brian_UK
03-11-2006, 10:59 PM
Going back to the original question....


I have air2water heat pump, the refrigerant is R410A. Time-to-time I have to deflate gas from radiators.
How to determine, is this gas air or R410A?
To test the vented air/gas use an electronic refrigerant leak detector. If you haven't got one then find someone who has.


Diffusion of small quantities of the R410A through refrigerant-water brazed plate heat exchanger - is it possible? Is it normal?Is it possible ? YES.

Is it normal ? NO.

stalker
23-11-2006, 01:49 PM
Detector showed no leakage.
Probably the reason is that when I used solid fuel boiler, the air issued partly through the automatic ventilation system of the boiler ring. Now all the air issues through the radiators.

Brian_UK
23-11-2006, 06:27 PM
Thanks for the update Stalker.

Gary
20-02-2007, 02:25 PM
Detector showed no leakage.
Probably the reason is that when I used solid fuel boiler, the air issued partly through the automatic ventilation system of the boiler ring. Now all the air issues through the radiators.

You may have insufficient cold fill pressure, allowing air to enter through the automatic ventilation system when the water is cold. Proper cold fill pressure depends upon the vertical height of the water system.

Measure the height of the system (in feet) and divide by 2. This gives you sufficient cold fill pressure (in psi). For example, if the height of the system is 50 feet, the cold fill pressure should be 25psi.

The Viking
20-02-2007, 05:20 PM
Stalker,
I fully agree with the other posts but let me expand on why.

Your plate heat exchanger are where the pressure in the refrigeration system is the highest, even a small leak there will rapidly empty the gas out of your system.

So, if there were a leak your question wouldn't be "is it R410A coming from my radiator" but instead "Why isn't my heat-pump warming the water as it used to?"

DeB
24-02-2007, 01:48 AM
I would suggest the reason for the high number of "air leakages" may be due to the design of the pipe work which does not allow the air to vent through the autovents and traps in the radiators. Make sure there is sufficient head from the makeup tank and check the pipe loop and position of autovents.