A/C Gauge Readings

[Jango]

2007 CRV and it's A/C runs cold but shuts off intermittently. I have swapped around relays and I think they are working.

Here are the readings at idle and at 2500 rpm respectively taken at 90-95 F with humidity less than 30. Need some advice please.

 

[Eddie Hudson]

1. HOW TO
2. DIAGRAMS: SYSTEM PRESSURE CHART

Get a quick look at what an average A/C system looks like, along with the compressor manufacturer and what the specific R-134a requirements are for your car.

R-134a TEMPERATURE PRESSURE CHART (Tabla de Temperaturas y Lecturas)
Ambient Temperature °F / °C (Temperatura Ambiental)	Low-Pressure Gauge (Puerto de Servicio del Lado de Baja Presion)	High-Pressure Gauge (Puerto de Servicio del Lado de Lado de Alta Presion)
65°F (18°C)	25-35 psi / 172-241 kPa	135-155 psi / 931-1069 kPa
70°F (21°C)	35-40 psi / 241-276 kPa	145-160 psi / 1000-1103 kPa
75°F (24°C)	35-40 psi / 241-310 kPa	150-170 psi / 1034-1172 kPa
80°F (27°C)	40-50 psi / 276-345 kPa	175-210 psi / 1207-1448 kPa
85°F (29°C)	45-55 psi / 310-379 kPa	225-250 psi / 1551-1724 kPa
90°F (32°C)	45-55 psi / 310-379 kPa	250-270 psi / 1724-1862 kPa
95°F (35°C)	50-55 psi / 345-379 kPa	275-300 psi / 1896-2068 kPa
100°F (38°C)	50-55 psi / 345-379 kPa	315-325 psi / 2172-2241 kPa
105°F (41°C)	50-55 psi / 345-379 kPa	330-335 psi / 2275-2310 kPa
110°F (43°C)	50-55 psi / 345-379 kPa	340-345 psi / 2344-2379 kPa
Ambient temp is the outside atmospheric temperature.

INTERPRETING PRESSURE READINGS
Low-Pressure Gauge	High-Pressure Gauge	Action Required
IN RANGE	IN RANGE	A/C is working properly.
LOW	LOW	Add Refrigerant.
LOW	HIGH	Need service, possible blockage of the expansion valve or orifice tube.
HIGH	LOW	Needs service, possibly faulty compressor.
HIGH	HIGH	System is overcharged. Slowly remove refrigerant. Venting is illegal in USA.

 

[atikovi]

I'm no a/c expert but the low side in the second picture is at 10 psi which would make the low pressure switch kick in and turn the system off. I'd say it's low on freon.

 

[21_6.7f450]

take it to an AC pro, evacuate, pull a vacuum for an hour, make sure it holds and recharge with amount listed on the underhood sticker.
YOu have gauges, but aren't sure what's going on. That can cost thousands. I would roll into a shop and get their advice in person.

 

[RooflessVW]

Looks low. Evaluate for leaks and service.

 

[wag123]

I agree with others that the system looks to be low on freon, but on Hondas from this era you can't discount the possibility that the compressor clutch is slipping.

 

[Mechanician]

Because you stated it runs cold, it's likely low charge.
A slipping clutch will become blue, and burnt looking in short order.
Where the ports are in the system, and what the pressures do in live time, is always a consideration.

Example - If there's a blockage - the high side can start out at the 225-250 called for, then drop low as shown - as the refrigerant sits in the condenser and cools, over a very short period.
If the high side port is before, or after any blockage, will obviously affect the readings.

 

[KJSmith]

I'm far from an expert on car systems.
Assuming this is a 134a system.
You can look up online approximate "normal" pressures.

Why did you choose 2500 rpm???
On the few systems I have charged (all personally owned).... I charge at normal cruising RPM....1500-1800 rpm.

On your low side gauge, there are two inner rings that read out in temperature f/c.
The inner most ring is *F.
You need that to stay above 32f/0c at normal cruising speed or the condensate on the evap coil will freeze.
In your second picture you are well below that.

As always..... Take it to someone who knows what they are doing.
You will be better off in the long run.

 

[Donald]

take it to an AC pro, evacuate, pull a vacuum for an hour, make sure it holds and recharge with amount listed on the underhood sticker.
YOu have gauges, but aren't sure what's going on. That can cost thousands. I would roll into a shop and get their advice in person.

+ 1 - remember the system is a closed system. If some refrigerant has leaked out then there is a leak.

Dried o-ring? Schrader valve? Condenser?

Do you have a R134a detector?

System gets filled by weight, not by pressure. After you pull a vacuum for 30 min and it holds.

 

[Mechanician]

If the high side port is before, or after any blockage, will obviously affect the readings.

This was poorly written.
Edit above to : Whether the high side ....

 

[clinebarger]

I'm no a/c expert but the low side in the second picture is at 10 psi which would make the low pressure switch kick in and turn the system off. I'd say it's low on freon.

Honda doesn't normally use a low side pressure switch but a Evaporator Temp Sensor.

 

[Nukeman7]

Honda doesn't normally use a low side pressure switch but a Evaporator Temp Sensor.

I'm pretty certain that a 2007 CR-V with the K24 motor has a low-pressure compressor cut out switch just like the Accord shown in this video.

 

[clinebarger]

As seen in the preview picture...That pressure switch is on the liquid high side.

 

[Jango]

To be safe, I took it to a shop recommended by a friend and they said the whole system needed to be replaced to the tune of $1750. I told them I would think it over. It now doesn't run cold one bit so I called them and they said the system was empty to begin with. I pulled a gauge reading right before I brought it in and it read similar to the first picture. Were they legit? Maybe. Not sure.

 

[atikovi]

To be safe, I took it to a shop recommended by a friend and they said the whole system needed to be replaced to the tune of $1750.

They don't know what the problem is and want to replace everything when maybe just a 50 cent seal is bad. Add 8 oz freon and retest. Even if you have to add it every month, that's still cheaper than spending that much.

 

[WobblyElvis]

Spend less that $20, add some r134a. The pressure chart is telling you to do just that.

 

[RooflessVW]

Spend less that $20, add some r134a. The pressure chart is telling you to do just that.

Sure, but who knows the current status of his system.

 

[Jango]

Does the compressor need to engage to charge it?
WIll the charger engage if currently no freon in it?

 

[atikovi]

Does the compressor need to engage to charge it?
WIll the charger engage if currently no freon in it?

The pressure in the can should raise the pressure in the system enough to engage the compressor.

 

[Nukeman7]

As seen in the preview picture...That pressure switch is on the liquid high side.

I stand corrected...you are right, Cline...as usual!