Air conditioning woes
Discussion
I'd appreciate it if anyone could shed any light onto this for me, our vans AC is playing up, I've got the gauges and diagnostic software to see what's going on but I'm stumped at the moment.
What is happening is the AC is switching on and off, say 10 seconds on, 10 seconds off, rinse and repeat. The pressures seem ok, about 70PSI on both sides when its off, running the low side drops to about 30 and the high goes up to about 170, when it switches off they both equalise again. The diagnostics is reporting 8 bar when off and about 12 bar when running, it must just monitor the high side. however the evaporator temp reports ambient temp when off (say 18 today) which is consistent with the outside air temp but when the AC triggers the reading runs down to about -3 and it immediately switches off again, I think the ECU is switching the AC off because it thinks its getting too cold.
The blower is working fine, there is plenty of air coming out of the vents and I've even removed the cabin/pollen filters (which were pretty dirty) to make sure there aren't any blockages anywhere. It has this problem whether its ticking over stationary or doing 70 on the motorway, you can feel the air getting cold then warm every few seconds.
Other than a faulty evap sensor, what could cause the evaporator to get too cold and shut down?
The van is a 2020 Peugeot expert 2.0HDI, I will say there has been a couple of strange noises recently when first switching the AC on, slight grinding noise maybe for a couple of seconds, not sure where its coming from as not had time to investigate yet.
What is happening is the AC is switching on and off, say 10 seconds on, 10 seconds off, rinse and repeat. The pressures seem ok, about 70PSI on both sides when its off, running the low side drops to about 30 and the high goes up to about 170, when it switches off they both equalise again. The diagnostics is reporting 8 bar when off and about 12 bar when running, it must just monitor the high side. however the evaporator temp reports ambient temp when off (say 18 today) which is consistent with the outside air temp but when the AC triggers the reading runs down to about -3 and it immediately switches off again, I think the ECU is switching the AC off because it thinks its getting too cold.
The blower is working fine, there is plenty of air coming out of the vents and I've even removed the cabin/pollen filters (which were pretty dirty) to make sure there aren't any blockages anywhere. It has this problem whether its ticking over stationary or doing 70 on the motorway, you can feel the air getting cold then warm every few seconds.
Other than a faulty evap sensor, what could cause the evaporator to get too cold and shut down?
The van is a 2020 Peugeot expert 2.0HDI, I will say there has been a couple of strange noises recently when first switching the AC on, slight grinding noise maybe for a couple of seconds, not sure where its coming from as not had time to investigate yet.
Frane Selak said:
I'd appreciate it if anyone could shed any light onto this for me, our vans AC is playing up, I've got the gauges and diagnostic software to see what's going on but I'm stumped at the moment.
What is happening is the AC is switching on and off, say 10 seconds on, 10 seconds off, rinse and repeat. The pressures seem ok, about 70PSI on both sides when its off, running the low side drops to about 30 and the high goes up to about 170, when it switches off they both equalise again. The diagnostics is reporting 8 bar when off and about 12 bar when running, it must just monitor the high side. however the evaporator temp reports ambient temp when off (say 18 today) which is consistent with the outside air temp but when the AC triggers the reading runs down to about -3 and it immediately switches off again, I think the ECU is switching the AC off because it thinks its getting too cold.
The blower is working fine, there is plenty of air coming out of the vents and I've even removed the cabin/pollen filters (which were pretty dirty) to make sure there aren't any blockages anywhere. It has this problem whether its ticking over stationary or doing 70 on the motorway, you can feel the air getting cold then warm every few seconds.
Other than a faulty evap sensor, what could cause the evaporator to get too cold and shut down?
The van is a 2020 Peugeot expert 2.0HDI, I will say there has been a couple of strange noises recently when first switching the AC on, slight grinding noise maybe for a couple of seconds, not sure where its coming from as not had time to investigate yet.
Is the condenser fan running?What is happening is the AC is switching on and off, say 10 seconds on, 10 seconds off, rinse and repeat. The pressures seem ok, about 70PSI on both sides when its off, running the low side drops to about 30 and the high goes up to about 170, when it switches off they both equalise again. The diagnostics is reporting 8 bar when off and about 12 bar when running, it must just monitor the high side. however the evaporator temp reports ambient temp when off (say 18 today) which is consistent with the outside air temp but when the AC triggers the reading runs down to about -3 and it immediately switches off again, I think the ECU is switching the AC off because it thinks its getting too cold.
The blower is working fine, there is plenty of air coming out of the vents and I've even removed the cabin/pollen filters (which were pretty dirty) to make sure there aren't any blockages anywhere. It has this problem whether its ticking over stationary or doing 70 on the motorway, you can feel the air getting cold then warm every few seconds.
Other than a faulty evap sensor, what could cause the evaporator to get too cold and shut down?
The van is a 2020 Peugeot expert 2.0HDI, I will say there has been a couple of strange noises recently when first switching the AC on, slight grinding noise maybe for a couple of seconds, not sure where its coming from as not had time to investigate yet.
E-bmw said:
Frane Selak said:
finlo said:
Is the condenser fan running?
I think so, from what I can see there is only one fan behind the radiator, not had time to have a proper look down there yet.Frane Selak said:
What is happening is the AC is switching on and off, say 10 seconds on, 10 seconds off, rinse and repeat. The pressures seem ok, about 70PSI on both sides when its off, running the low side drops to about 30 and the high goes up to about 170, when it switches off they both equalise again.
As you are already aware the fact that it is cycling like that means something is switching it off.The low pressure could be slightly low when running, is 30 the lowest it gets to as that is close to where many will cut off?
Perhaps try a little top-up with one of the DIY kits to see if that helps.
Frane Selak said:
The diagnostics is reporting 8 bar when off and about 12 bar when running, it must just monitor the high side. however the evaporator temp reports ambient temp when off (say 18 today) which is consistent with the outside air temp but when the AC triggers the reading runs down to about -3 and it immediately switches off again, I think the ECU is switching the AC off because it thinks its getting too cold.
8 bar is a little under 120 psi and 12 bar is 175 psi, so while one is lower than your reading the other is accurate.A low temperature when running or a low (low) pressure when running COULD indicate a partial blockage in the system, most likely in the area of the expansion valve where the HP turns to the LP side, or possibly the drier as they are normally close to each other in the system.
Frane Selak said:
The van is a 2020 Peugeot expert 2.0HDI, I will say there has been a couple of strange noises recently when first switching the AC on, slight grinding noise maybe for a couple of seconds, not sure where its coming from as not had time to investigate yet.
As above, for the cost of it I would start with a top-up and see what happens.Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff