Dashboard a/c not getting cold enough

[johnc58]

Hello everyone, my question is about the inside dashboard a/c not getting that cold. Is this a common issue or does it have a problem needing to get fixs. We do use the rooftop a/c but at times like to be able to use the dashboard a/c.

[Ranger Smith]

It could be a couple of things. Could be the mixing valve actuator in the AC box is bad and not closing and letting warm air in with the AC air or it could need a top off on refrigerant. A set of gauges on that would be able to tell if it needs charging.

It would also help if you had your RV info in your signature or told us what kind of rv you have.

[Skip426]

Dash A/C is considered , barely adequate in hot weather in most coaches , there are some test you can run with a thermometer to see if maybe a refrigerant top up will help.

Is this a new problem or a question about a new to you coach ?

[Gary RVRoamer]

Ranger covered the two main possibilities. Both are fairly common problems in motorhome dash a/c. I've also seen a heater valve stuck open, so the chilled air gets heated as it flows through the system.


If you are somewhat technically inclined, you could try topping up the refrigerant with a kit from an auto parts store. They aren't real expensive. The gauge on the kit will tell you if it needs more refrigerant or not (but you've already bought the kit). If that fixes the problem, be prepared to repeat it regularly because there is a leak somewhere in the system. Most owners will use an a/c shop to get that repaired, but if it only needs refrigerant 1-2 times/year you might decide to just live with it.


If that doesn't fix the problem, you may have one of the two mechanical valve issues mentioned. You probably want an automotive a/c shop for that unless you have good skills.

[Talloaks]

Yes, it is a very common issue. If you do a search, you will find multiple current threads on this topic, all of which will provide you with helpful information.

The particular info you need will depend on your specific rig, so if you want specific help, you could post the details of your rig and exactly what you have attempted or observed so far.

Note that one leading RV HVAC OEM (Evans/Tempcon) states in their tech manual that it is likely necessary to add refrigerant every year, as it is difficult to maintain an RV A/C system completely leak-free.

However, there are multiple other likely causes for cooling system performance issues besides low refrigerant level.

[johnc58]

Originally Posted by johnc58

Hello everyone, my question is about the inside dashboard a/c not getting that cold. Is this a common issue or does it have a problem needing to get fixs. We do use the rooftop a/c but at times like to be able to use the dashboard a/c.

We have a 2007 Newmar Kountry Star 3916 diesel 350hp

[Skip426]

Do you have any idea what brand of dash A/C unit Newmar used in your coach ?

Denso ? Evans ?

Evans Systems are usually easy to spot by the housing above the genset .

Possible problems are , low on refrigerant or coolant flow valve not properly shutting off hot coolant into the dash.

[Talloaks]

If Evans, here is a link to a good manual on understanding and troubleshooting your system.

https://www.proairllc.com/pub/media/...ice_Manual.pdf

[Pez Vela]

Originally Posted by Skip426

Do you have any idea what brand of dash A/C unit Newmar used in your coach ?



Denso ? Evans ?



Evans Systems are usually easy to spot by the housing above the genset .



Possible problems are , low on refrigerant or coolant flow valve not properly shutting off hot coolant into the dash.

Skip. I saw the pic you posted of the Evans . Is this on your rig? If so, what kind of RV?. I have a 1999/2000 Coachmen Santara DP, 37 ft. My Evans label does not show the required amount of refrigerant. It was left blank from the factory. I recently was getting hot air from the dash. I took it to a shop. They hooked it to an A/C machine. Evacuated the system. It removed 7 lbs of refrigerant. The mechanic thought this was too much. Since we don't have any info on the correct amount, he put 5.5 lbs back in. Seems to work better but not outstanding.
Your photo indicates 3.5 lbs. Just wondering if that is correct considering the long run from dash to engine mounted compressor in rear? At 5.5 lbs, I might still have too much refrigerant. Your thoughts?

[THenne1713]

Originally Posted by johnc58

Hello everyone, my question is about the inside dashboard a/c not getting that cold. Is this a common issue or does it have a problem needing to get fixs. We do use the rooftop a/c but at times like to be able to use the dashboard a/c.

While most common issue is low on freon, SUDDEN warm air from dash when DRIVING and controls set to cold can be FIRST SYMPTOM OF ENGINE OVERHEAT. If vehicle uses electric radiator fans, can also be a symptom of failed fan/ fan motor, or broken/ missing blades.

[PanJH]

I have the same issue with warm air. The label on my evans unit is blank... doesn't indicate charge amount.

I have a set of gauges. what should the high/low pressures be ?

[bpu699]

Originally Posted by Talloaks

Yes, it is a very common issue. If you do a search, you will find multiple current threads on this topic, all of which will provide you with helpful information.

The particular info you need will depend on your specific rig, so if you want specific help, you could post the details of your rig and exactly what you have attempted or observed so far.

Note that one leading RV HVAC OEM (Evans/Tempcon) states in their tech manual that it is likely necessary to add refrigerant every year, as it is difficult to maintain an RV A/C system completely leak-free.

However, there are multiple other likely causes for cooling system performance issues besides low refrigerant level.

Hmmmm... I would think refilling every year is a bad idea. The issue is you don't know how much oil you have in the system. Too little, it blows up... Too much, it doesnt work.

How does one gauge oil requirements?

[Dutch Star Don]

Originally Posted by johnc58

Hello everyone, my question is about the inside dashboard a/c not getting that cold. Is this a common issue or does it have a problem needing to get fixs. We do use the rooftop a/c but at times like to be able to use the dashboard a/c.

John.....your coach is 15+ years old and there could be a variety of reasons why the dash AC is no longer blowing cold. Unless you're very familiar with working on AC units, I would take it to a professional. If it's the most typical issue, which is low on freon, it could cause your AC compressor to seize while driving, (if you have it on) breaking your engine belts.


So, I would either leave it off or have a professional test it and see what the issue is. Usually about $250 - $350 for a recharge. It doesn't have to go to an RV repair shop, just an AC shop that has the space for the coach.

[PanJH]

Originally Posted by Dutch Star Don

John.....your coach is 15+ years old and there could be a variety of reasons why the dash AC is no longer blowing cold. Unless you're very familiar with working on AC units, I would take it to a professional. If it's the most typical issue, which is low on freon, it could cause your AC compressor to seize while driving, (if you have it on) breaking your engine belts.


So, I would either leave it off or have a professional test it and see what the issue is. Usually about $250 - $350 for a recharge. It doesn't have to go to an RV repair shop, just an AC shop that has the space for the coach.

My compressor froze up back in May... broke the belt and then you overheat since the water pump is driven by that belt..... but, the compressor clutch should disengage when the low side pressure drops... or so I've read. I don't know what root cause was with mine, but it left me on the side of the road. Compressor was locked up solid