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brian connolly
09-12-2011, 09:18 PM
hey lads. what can cause frosting around the expansion valve? its a ground source heat pump

refcon32
09-12-2011, 10:21 PM
If you are talking about frosting round the valve and control motor, it is probably a refrigerant leak on the expansion valve, caused by the bellows cracking due to moisture and releasing refrigerant. Need to replace the expansion valve and motor, making sure to torque the motor to valve body to stop this happening again. Recover refrigerant and weigh quantity to known charge weight to prove refrigerant loss.

Peter_1
10-12-2011, 08:48 AM
Brian, we install a lot of GSHP. Frosting around the valve is because your system is running below 0°C. What are your running pressures and temperatures? Frosting around the valve this time of the year and so early in the heating season is strange, unless to less coils were installed.

Peter_1
10-12-2011, 09:01 AM
@Refcon, why you think there's a motor? Where's the bellow on an EEV? Refrigerant loss can be found simply by verifying running pressures and temperatures without prior recovering. It perhaps was never charged correct the first time. I never depend on what others did before me.

mad fridgie
10-12-2011, 09:09 AM
Without stating the obvious,could be that the system has just been turned on (cold water in the heating circuit)
and the condensing pressure is just low, because of the water temp fact. The suction will follow.

r.bartlett
10-12-2011, 04:35 PM
If you are talking about frosting round the valve and control motor, it is probably a refrigerant leak on the expansion valve, caused by the bellows cracking due to moisture and releasing refrigerant. Need to replace the expansion valve and motor, making sure to torque the motor to valve body to stop this happening again. Recover refrigerant and weigh quantity to known charge weight to prove refrigerant loss.

Please expand on this as I cannot follow the logic at all..

refcon32
10-12-2011, 09:02 PM
Thought the expansion valve was the type that has L shaped pipework and a drive motor sits on top to operate the valve by pushing the pin in and out of valve body to control fridge flow. As on airconditioning systems. Sorry for confusion
Please expand on this as I cannot follow the logic at all..

desA
10-12-2011, 10:09 PM
Without stating the obvious,could be that the system has just been turned on (cold water in the heating circuit)
and the condensing pressure is just low, because of the water temp fact. The suction will follow.

I wonder what type of pump control this heat-pump has? Interesting point MF.

Peter_1
11-12-2011, 12:24 PM
Please expand on this as I cannot follow the logic at all..
Me neither Richard

r.bartlett
11-12-2011, 07:54 PM
Thought the expansion valve was the type that has L shaped pipework and a drive motor sits on top to operate the valve by pushing the pin in and out of valve body to control fridge flow. As on airconditioning systems. Sorry for confusion

Ok but where are the bellows on a EEV
(as Peter asked previously?)

brian connolly
11-12-2011, 09:32 PM
thanks for replies lads. just to elaborate on problem,the frosting is actually on the pipe coming from the expansion valve. i have recently done a short fgas course but am a complete novice. i have installed a lot of nibe pumps and never needed to know about the refrigeration side of them. this heat pump is a neura and the compressor is in a plastic container dropped into the lawn of a lads house. his controls are very industrial looking. when he switches on his heating the the controller registers a fault after a few minutes. when i went out to look at compressor, i noticed the frost on the pipe. the compressor can be heard running but no heat is produced.

install monkey
11-12-2011, 09:43 PM
have u got gauges,what running pressures are u getting. what fault code

r.bartlett
11-12-2011, 10:22 PM
I thought F-Gas wasn't for complete novices..How nieve am I? :-/

al
11-12-2011, 11:42 PM
Brian

if you're stuck i can give you a digout, pm me.

alec

refcon32
12-12-2011, 12:48 AM
The bellows are on main valve body where the output shaft of drive motor enter the valve.

Ok but where are the bellows on a EEV
(as Peter asked previously?)

Peter_1
12-12-2011, 06:53 AM
A shaft seal then?

Lodiev
12-12-2011, 09:51 AM
It sounds to me like the system haze a gas leak, phone a technician as u are going to break it if u do not have the experience to fix this simple problem. u will also then be sure that the system will function as designed.
No comebacks.

refcon32
12-12-2011, 09:21 PM
I should have a working diagram of the valve I am talking about. will look it out and put it on and all will be explained
A shaft seal then?