Air Conditioning Problem

Air Conditioning Problem

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Discussion

Simonuk

Original Poster:

12 posts

159 months

Thursday 14th April 2016
quotequote all
Hi all,

We have a problem with the air conditioning on our M12 3R.

The air conditioning does get cold quickly but can hear the AC compressor clutch engaging and disengaging every 10 seconds or so.

Could this be something as simple as low refrigerant?

The AC sight glass is green and the system pressure has been measured at 80 psi. Possibly too low?

What is the correct level of refrigerant required for a full re-gas? The manual mentions 1.4 pounds (635 grams) but I have heard 950 grams mentioned a few times on the forum.

Any help would be much appreciated!

Simon


wessexrfc

4,326 posts

193 months

Thursday 14th April 2016
quotequote all
Simonuk said:
Hi all,

We have a problem with the air conditioning on our M12 3R.

The air conditioning does get cold quickly but can hear the AC compressor clutch engaging and disengaging every 10 seconds or so.

Could this be something as simple as low refrigerant?

The AC sight glass is green and the system pressure has been measured at 80 psi. Possibly too low?

What is the correct level of refrigerant required for a full re-gas? The manual mentions 1.4 pounds (635 grams) but I have heard 950 grams mentioned a few times on the forum.

Any help would be much appreciated!

Simon
Hi Simon, yes it sounds like its low, 800-900 grams should be about right. Take it to a local refrigeration company who can charge the system with good digital scales and monitor both high and low sides to insure its evaporating and condensing correctly. HTH

Midlifecrisis71

2,871 posts

282 months

Friday 15th April 2016
quotequote all
Mine cuts in and out during constant operation, about every minute or 2

I assumed that was normal ?

Simonuk

Original Poster:

12 posts

159 months

Saturday 16th April 2016
quotequote all
Sounds like it would wear the clutch out to me.

Anyone else experience the same thing?

Simonuk

Original Poster:

12 posts

159 months

Monday 18th April 2016
quotequote all
We've had the AC recharged to 950 grams with no difference. The compressor clutch engages for 10 seconds then disengages for about 30 seconds and cycles like that...

AMG Merc

11,954 posts

260 months

Monday 18th April 2016
quotequote all
Interesting. Perhaps have the belt tension checked?

verba1

628 posts

175 months

Monday 18th April 2016
quotequote all
Simonuk said:
We've had the AC recharged to 950 grams with no difference. The compressor clutch engages for 10 seconds then disengages for about 30 seconds and cycles like that...
I had 1kg recharge by my MV last year and works well . I think the cycle on mine once it's on and driving for a bit is about 30 seconds . It seems to have always done the same without any problems yet !


wessexrfc

4,326 posts

193 months

Monday 18th April 2016
quotequote all
Simonuk said:
We've had the AC recharged to 950 grams with no difference. The compressor clutch engages for 10 seconds then disengages for about 30 seconds and cycles like that...
This WILL be a pressure switch problem. It could be the hp or Lp, (high pressure or low pressure) This is why you need it charged by a refrigeration engineer rather than a mechanic type fitter to make sure its not over-charged. They will have gauges to monitor both the hp and Lp to see whats happening while its in operation and to trace where its cutting out. I very much doubt its the clutch. Hth

Midlifecrisis71

2,871 posts

282 months

Tuesday 19th April 2016
quotequote all
wessexrfc said:
This WILL be a pressure switch problem. It could be the hp or Lp, (high pressure or low pressure) This is why you need it charged by a refrigeration engineer rather than a mechanic type fitter to make sure its not over-charged. They will have gauges to monitor both the hp and Lp to see whats happening while its in operation and to trace where its cutting out. I very much doubt its the clutch. Hth
Paul - Ive researched all the old posts on aircon (sad I know) and most of the owners from 2005 onwards are saying they all do the 15-20 second cycle of cutting in and out, you just hear the relay and the clutch engaging every 30 seconds or so, and add they have done it since new.

Mine blows cool (not cold) so may want re-gassing anyway.... can you recommend someone ?
But I think the relay clicking in and out is normal.

I bow to your knowledge on the subject tho, as you know your aircon

F.C.

3,897 posts

215 months

Wednesday 20th April 2016
quotequote all
My 400 had a similar problem turned out to be the trinary switch on the drier canister, (I think that's what its called) anyway the canister with the sight glass.

AMG Merc

11,954 posts

260 months

Wednesday 20th April 2016
quotequote all
F.C. said:
My 400 had a similar problem turned out to be the trinary switch on the drier canister, (I think that's what its called) anyway the canister with the sight glass.
Watcha Tone wavey

F.C.

3,897 posts

215 months

Wednesday 20th April 2016
quotequote all
AMG Merc said:
Watcha Tone wavey
Hey Rob,

How's that Dancing Donkey going (up in price I'll bet)?

AMG Merc

11,954 posts

260 months

Thursday 21st April 2016
quotequote all
F.C. said:
Hey Rob,

How's that Dancing Donkey going (up in price I'll bet)?
He's looking sweet thanks Tony. All jobs done and about to go into storage (so I can get Nobby out!) bounce

wessexrfc

4,326 posts

193 months

Friday 22nd April 2016
quotequote all
Midlifecrisis71 said:
wessexrfc said:
This WILL be a pressure switch problem. It could be the hp or Lp, (high pressure or low pressure) This is why you need it charged by a refrigeration engineer rather than a mechanic type fitter to make sure its not over-charged. They will have gauges to monitor both the hp and Lp to see whats happening while its in operation and to trace where its cutting out. I very much doubt its the clutch. Hth
Paul - Ive researched all the old posts on aircon (sad I know) and most of the owners from 2005 onwards are saying they all do the 15-20 second cycle of cutting in and out, you just hear the relay and the clutch engaging every 30 seconds or so, and add they have done it since new.

Mine blows cool (not cold) so may want re-gassing anyway.... can you recommend someone ?
But I think the relay clicking in and out is normal.

I bow to your knowledge on the subject tho, as you know your aircon
I can get that sorted mate, mine needs regassing after all the engine work, so I could get both done. Good excuse for you to have a trip to the best part of Devon for a brew!!!

wessexrfc

4,326 posts

193 months

Friday 22nd April 2016
quotequote all
F.C. said:
My 400 had a similar problem turned out to be the trinary switch on the drier canister, (I think that's what its called) anyway the canister with the sight glass.
Sorry, yes you are right, I'm using refrigeration terminology, this is a very good video to better understand our systems:
https://www.youtube.com/watch?v=l604JCZx_ow

Midlifecrisis71

2,871 posts

282 months

Friday 22nd April 2016
quotequote all
wessexrfc said:
I can get that sorted mate, mine needs regassing after all the engine work, so I could get both done. Good excuse for you to have a trip to the best part of Devon for a brew!!!
Let me know where and when ! Thanks

wessexrfc

4,326 posts

193 months

Monday 25th April 2016
quotequote all
Midlifecrisis71 said:
wessexrfc said:
I can get that sorted mate, mine needs regassing after all the engine work, so I could get both done. Good excuse for you to have a trip to the best part of Devon for a brew!!!
Let me know where and when ! Thanks
Message sent