[JLS]

Originally Posted by audioholic

Kind of a technical doubt which I am sure of a salesman or his manager or even the service guys not giving a satisfactory reply. If anyone knows in detail about the AC in the ertiga, I wanted to know what happens to the refrigerant in the Rear evaporator when the blower isn't used? Is the flow of refrigerant stopped when the rear blower isn't used? Some other cars like the Evalia, Innova, Mobilio have a switch to power up the rear AC which I think is also used to control the flow of refrigerant gas.

Suppose the gas circulates through the rear evaporator without fresh air passing through it, it will start forming icicles and eventually corrode in the long run. How I this issue addressed in the mobilio? Even if the evaporator is made out of a corrosion resistant material, the accumulated water will also promote microbial growth since the drain pipe will not completely dry the area always.

So far I have not noticed water drops in rear seat, even after a long drive, where in only front AC was used.
There would be definetely some water droplets present, if coolent is flowing in rear coils for a long time without fresh air going over it.
So we can infer that coolent flow in rear evaporater coils are managed and controlled intelligently through a valve, and flow is switched off if rear AC fan is off.

I am not totally sure, how it is done in Ertiga, but probably it would have been implemented it in the following fashion:
Scenario 1: Front AC on, rear AC off (fan switch off) - A valve remains closed and shuts off circulation of coolent in rear coils
Secnario 2: Front AC on, rear AC on (fan switch on) - A valve opens and allows coolent circulation in rear coils
Scenario 3: Front AC off, rear AC on (fan switch on) - Valve remains off, as front AC is off

So in nutshell, valve controlling circulation in rear AC coils opens only if both units are switched on. Hence no circulation of coolent if rear AC/fan is off.
However, only Maruti technician may be able to confirm, how the coolent circulation in rear AC coils is controlled.

Regards,
JLS

[paragsachania]

Originally Posted by audioholic

Kind of a technical doubt which I am sure of a salesman or his manager or even the service guys not giving a satisfactory reply. If anyone knows in detail about the AC in the ertiga, I wanted to know what happens to the refrigerant in the Rear evaporator when the blower isn't used? Is the flow of refrigerant stopped when the rear blower isn't used? Some other cars like the Evalia, Innova, Mobilio have a switch to power up the rear AC which I think is also used to control the flow of refrigerant gas.

Suppose the gas circulates through the rear evaporator without fresh air passing through it, it will start forming icicles and eventually corrode in the long run. How I this issue addressed in the mobilio? Even if the evaporator is made out of a corrosion resistant material, the accumulated water will also promote microbial growth since the drain pipe will not completely dry the area always.

Good Question and honestly, I need to figure this out myself. I look at rear AC of Ertiga and Mobilio as Air Handling Units or Fan coil units used to regulate and circulate cool/hot air as part of the main AC Unit and not necessarily as a second AC itself - It has a dependency on the Primary AC.

Since the rear blower also has a cooling/Evaporator coil, the AC gas comes into picture like you mentioned. So you do have a valid point on what happens when the rear blower is not used over long run.

However, when you mention this (Some other cars like the Evalia, Innova, Mobilio have a switch to power up the rear AC), I am sure that the Ertiga also has the Switch to power up the rear like the Mobilio. But this switch on both Mobilio and Ertiga will turn on the Blower Unit which has a direct dependency on the air blown by the front AC as it sucks air and cools it further. Without the front AC On, the rear is 100% a blower and nothing else.

Innova on the other hand has Dual Air-conditioning units that can work independently if I recall it right (with a single large capacity compressor?).

Whenever I turn the AC on, irrespective of the blower position, I do get a faint hissing noise from the rear unit for 3-5 seconds indicating the flow of gas (may be).

[gautamkhadse]

Just wanted to let everyone know , that I have upgraded the tyres on my ertiga to MRF ZLO .

I opted for 205 60 R 15 . The Ertiga feels even more planted now and the ride is plush . It might be psychological but I like it now . I need to get alloys now ( aftermarket ones ) because I bought a ZDI without alloys . I need to find a proper 5 hole , 100 PCD , 6 J alloy design . Finding it hard to find something that will suit the Ertiga .

The middle blower noises have been resolved by removing the entire roof lining and inserting foam padding between the Blower and the roof . I didnt see this being done but this is what was told to me . The guys at Sehgal Auto , Pune acknowledged that this was an issue acknowledged by Maruti and Maruti had sent them an official circular on how to fix these issues .

The hissing sounds from the front quarter glass have also been fixed . Maruti has also issued a ciircular on how to fix this issue as well

Rear beam assembly was replaced under warranty , I had seen a post by Kalinga that it was being replaced if there was some noise . There was some noise in my car aswell . So it was replaced .

Front suspension seemed to have some problem . even when it goes over small speed breakers that you have in malls and societies nowadays , it kinda jumps and creates a thud thud sound . They greased and lubricated the springs and the suspension . The noise is back after a week . I need to take this back to them .

The engine noise has increased after the 3rd service . The vibrations during the start and ignition off are unbearable .

seat vibrations are something I have learned to live with . the rubbing of art leather seats and the noise it creates is just horrible . I am going to try some DIY fixes to get rid of that noise . To start with am going to rub those surfaces with carrom powder or boric powder to see if it reduces the noise . And then try vaseline to see if that works .

[audioholic]

Originally Posted by JLS

So in nutshell, valve controlling circulation in rear AC coils opens only if both units are switched on. Hence no circulation of coolent if rear AC/fan is off.
However, only Maruti technician may be able to confirm, how the coolent circulation in rear AC coils is controlled.

In short that's exactly what I want to know. Whether there is any controlling valve or solenoid that can shut the rear evaporator when the rear blower isn't running. Guess you owners must quiz the SA during next service But honestly going by the amount of knowledge these SAs have, only a few can really answer such questions. The others are only fit for convincing you to avail AC cleaning if you utter the word AC.

Originally Posted by paragsachania

Good Question and honestly, I need to figure this out myself. I look at rear AC of Ertiga and Mobilio as Air Handling Units or Fan coil units used to regulate and circulate cool/hot air as part of the main AC Unit and not necessarily as a second AC itself - It has a dependency on the Primary AC.

).

AFAIK, innova has separate compressors for the higher end variants. Hence in that case it can be switched off when the rear unit isn't used. So I the case with safari as I am told.

Here in the case of Ertiga or Mobilio, they share the same compressor. The mobilio has a two stage switch for rear AC. One is in the dash and the other in the rear blower itself. Hence I believe the first switch is used for both sending power to rear blower and controlling gas flow. Else they wouldn't have provided a switch just for the driver to be able to control the rear blower motor. But in the Ertiga I believe the only way to switch on and switch off the rear blower is in the blower itself.

If it is a fact that the evaporator will be live(ie with gas circulating), then it will be fine even if the rear blower is run instead of leaving the evaporator live without air passing through it.

Guess you can ask the people in Suraksha since you're a regular customer. If I ask the people at Garuda, they are so dumb that it will lead to me teaching them the same Hence I don't want to risk it. There better be a mechanism to cut off refrigerant gas to the rear evaporator.

[paragsachania]

Originally Posted by gautamkhadse

I opted for 205 60 R 15 . The Ertiga feels even more planted now and the ride is plush . It might be psychological but I like it now .

Agree with you on the ride quality and improvement in handling as well. Mine's on same profile but XM2 since the last 7k kms.

I need to get alloys now ( aftermarket ones ) because I bought a ZDI without alloys . I need to find a proper 5 hole , 100 PCD , 6 J alloy design . Finding it hard to find something that will suit the Ertiga .

It was my apprehension as well. Very less choices for 5 Hole. Additionally, I am not at all sure if 6J will have choices and you will be left with only 6.5J to pick from and considering the design of wheel arches of the Ertiga, there is every possibility of the tires scrapping the arches on full load and undulated surface.

The middle blower noises have been resolved by removing the entire roof lining and inserting foam padding between the Blower and the roof . I didnt see this being done but this is what was told to me .

I tried to figure this out and placed some cushioning material below the blower unit but was useless. Realised that the noise if more from the very beginning of the unit (right above the front seat head restraints) and for that removing the roof lining was apparent. I refrained from going beyond this as I didn't want to do that. The noise levels are way too low from the rear blower and very occasional that I need to complain.

Rear beam assembly was replaced under warranty , I had seen a post by Kalinga that it was being replaced if there was some noise . There was some noise in my car aswell . So it was replaced .

You are right. I asked the works manager at the ASC in Bangalore and I was told that it is not a pro-active replacement mostly and they are replacing this only for the customers who complain about noise from rear suspension when passing over bad roads and the car swaying sideways (one rear tire at a time type situations).

Front suspension seemed to have some problem . even when it goes over small speed breakers that you have in malls and societies nowadays , it kinda jumps and creates a thud thud sound . They greased and lubricated the springs and the suspension . The noise is back after a week . I need to take this back to them .

Check is the caliper pins are the culprit. I went to Coorg last weekend and since it was raining and the car went over a lot of stagnant water, soon after I reached Bangalore and drove to work next day, I started to listen to this thud noise on bad surfaces. When I parked the car in office, I hit the sidewalls of the front tires and could easily listen to the metal clanks hinting me that it was indeed the calipers. I am yet to grease them but I am sure its nothing but the calipers as I suspect the grease to have completely dried in the event of driving the car under gushing waters at many places on the road.

The engine noise has increased after the 3rd service . The vibrations during the start and ignition off are unbearable .

Wondering what could be the reason here as a mere oil change cannot make things noisy.

seat vibrations are something I have learned to live with . the rubbing of art leather seats and the noise it creates is just horrible . I am going to try some DIY fixes to get rid of that noise . To start with am going to rub those surfaces with carrom powder or boric powder to see if it reduces the noise . And then try vaseline to see if that works .

Been lucky in this department so far. But I did notice that the noise is when 2nd row seats squeak and hence I mostly keep them in different sliding positions including the recline angle.

Originally Posted by audioholic

AFAIK, innova has separate compressors for the higher end variants. Hence in that case it can be switched off when the rear unit isn't used. So I the case with safari as I am told.

Yes, you are right.

The mobilio has a two stage switch for rear AC. One is in the dash and the other in the rear blower itself. Hence I believe the first switch is used for both sending power to rear blower and controlling gas flow. Else they wouldn't have provided a switch just for the driver to be able to control the rear blower motor. But in the Ertiga I believe the only way to switch on and switch off the rear blower is in the blower itself.

Help me understand here how Mobilio and Ertiga are different in case of rear AC blower unit and their controls? Both have a primary switch on the Dash to turn the AC compressor on. Both have a 3 speed blower switch to Turn the rear unit on as well as control the fan speed. Both of them have a cooling coil along with a Fan and suction vents which make the rear units dependent on the front AC (and the temperature) to be effective.

Guess you can ask the people in Suraksha since you're a regular customer.

I surely will & may be try to check the workshop manual and parts catalog to understand it better and post it here.

Thanks for bringing this up!

[audioholic]

Originally Posted by paragsachania

Help me understand here how Mobilio and Ertiga are different in case of rear AC blower unit and their controls? Both have a primary switch on the Dash to turn the AC compressor on. Both have a 3 speed blower switch to Turn the rear unit on as well as control the fan speed. Both of them have a cooling coil along with a Fan and suction vents which make the rear units dependent on the front AC (and the temperature) to be effective.

Firstly, there was a confusion in me regarding the switch marked "Rear" in the AC console of the Mobilio. Now that I wanted to attach the related image here, I found out that the switch was of the rear defogger. Sorry for that


Next, the doubt still remains, just that the Mobilio is similar to the Ertiga and it doesnt have a switch as shown in the Evalia:



Hence, with the absence of this switch in both the Ertiga and the Mobilio, the question that remains is how the rear evaporator works.

[a4anurag]

Originally Posted by audioholic

Next, the doubt still remains, just that the Mobilio is similar to the Ertiga and it doesnt have a switch as shown in the Evalia:

Hence, with the absence of this switch in both the Ertiga and the Mobilio, the question that remains is how the rear evaporator works.

It is a common line so there shouldn't be a issue of stagnation and condensation when not used.

Anurag.

[audioholic]

Originally Posted by a4anurag

It is a common line so there shouldn't be a issue of stagnation and condensation when not used.

Anurag.

Nope I think you didn't get the issue we are speaking about. When the evaporator is live without air passage, water vapour condenses and forms ice.

[paragsachania]

Originally Posted by audioholic

Firstly, there was a confusion in me regarding the switch marked "Rear" in the AC console of the Mobilio. Now that I wanted to attach the related image here, I found out that the switch was of the rear defogger. Sorry for that

I wondered if that was the case, it is much better to what Ertiga has and Honda would advertised that as an additional feature.

Hence, with the absence of this switch in both the Ertiga and the Mobilio, the question that remains is how the rear evaporator works.

Originally Posted by audioholic

Nope I think you didn't get the issue we are speaking about. When the evaporator is live without air passage, water vapour condenses and forms ice.

You have a valid point as all fan coils units employ a coil, fan assembly, manual air vent (Inlet and outlet) and condensation drain outlet. Now this "drain" is what the question is all about. Where does it go out from?

[mohan41]

As the discussion is happening about the AC, I want to bring up a related topic. If outside air is cool as the case is in Bangalore nowadays mostly during evenings, I like to switch off the AC and just turn on the fan (I have good quality Bosch cabin air filter which takes care of dust and pollution, at least to some extent). I notice that the air coming out of the vents is warmer than the outside air. Is this the case with everyone else? If this is because the air from outside is sucked somewhere within the engine bay which is hot then I feel that the air suction vent is not placed in a good location.

[audioholic]

Originally Posted by paragsachania

You have a valid point as all fan coils units employ a coil, fan assembly, manual air vent (Inlet and outlet) and condensation drain outlet. Now this "drain" is what the question is all about. Where does it go out from?

When air is cooled by Evaporator, it condenses the water. This water flows down the coils(externally) and reaches the base of the duct or whichever is the lowest point naturally. The drain pipe will be connected to the base area of the duct which removes the water, but not completely. The base will still be wet. The continuous flow of air ensures that some amount of the condensed water is picked up again since water evaporates quickly in dry air. Also the continuous flow of air will ensure that water wont just stay within the evaporator.

Hence, when there is no airflow, the water goes on getting condensed and forms ice. In cold nights with continuous AC use, this can happen in any car. Here in this case, there wont be airflow when the rear blower is off. But, if the refrigerant is still circulated along the evap, firstly its a waste and secondly, this might cause ice formation just like a non-frost free refrigerator. This will eventually harm the coil.

Thus, my question is what is the measure taken by Maruti, Honda or anyone to avoid this issue? IN case of the main cooling coil at front, obviously we cant run compressor without turning On the blower, whereas the other way can be done. Hence, gas wont flow across the cooling coil when air doesnt pass through it. How about the rear coil?

Drain pipe: In your ertiga, I guess a drain pipe from the rear blower will run down on either pillar and this will be routed outside the car to drain any condensed water. Same thing with the front cooling coil too. But without airflow, either cooling coils will have ice formation as the water from surrounding air will be condensed layer by layer which would have otherwise drained out.

Originally Posted by mohan41

As the discussion is happening about the AC, I want to bring up a related topic. If outside air is cool as the case is in Bangalore nowadays mostly during evenings, I like to switch off the AC and just turn on the fan (I have good quality Bosch cabin air filter which takes care of dust and pollution, at least to some extent). I notice that the air coming out of the vents is warmer than the outside air. Is this the case with everyone else? If this is because the air from outside is sucked somewhere within the engine bay which is hot then I feel that the air suction vent is not placed in a good location.

Firstly, the air is sucked in from below the windshield in the front cowl area. Hence it will be a bit warm. However on cold nights the air might be quite cool as well. The placement is done in such a way to prevent rodents from entering the cabin, as well as keeping the inlet safe from water, dirt etc though some dirt may penetrate.
Next, the AC blows dry air which adds to the cooling effect. When you switch it off, you get humid air. Humid air adds to the warm effect just like dry air adds to the cold effect.

[paragsachania]

Originally Posted by audioholic

But without airflow, either cooling coils will have ice formation as the water from surrounding air will be condensed layer by layer which would have otherwise drained out.

This is exactly what I inferred when I replied you above. The answer would be found not by asking the ASC folks but by looking at the parts catalog and workshop manual to get schematic representation of the Rear Blower unit.

[interc00led]

Is there a separate expansion valve for the rear evaporator coil ?

[amitpunjani]

Originally Posted by audioholic

AFAIK, innova has separate compressors for the higher end variants. Hence in that case it can be switched off when the rear unit isn't used. So I the case with safari as I am told.

.

So Innova high end variant i.e. G or V have two compressor (front & rear), I seriously doubt that, I know for a fact they have separate Coiling coils/evaporator coils but two compressor i'm not sure?


Would appreciate if you could post a pic for second compressor as well.

Thanks

Amit

[swiftdiesel]

Originally Posted by amitpunjani

So Innova high end variant i.e. G or V have two compressor (front & rear), I seriously doubt that, I know for a fact they have separate Coiling coils/evaporator coils but two compressor i'm not sure?


Would appreciate if you could post a pic for second compressor as well.

Thanks

Amit

Innova has 2 compressors. If you watch closely, you'll find condensed water from the rear compressor dripping on the back right side, between the right tail lamp and right rear tyre. The compressor at the front drains its water out from under the engine bay.