gumbiegumbie Posted June 17, 2015 Share Posted June 17, 2015 I have a 01 ch613 and of its much hotter than about 85° you're just gonnao sweat. My question is, can an expansion valve work "a little"? My compressor is pumping, I weighed the freon in acording to the sticker, MY condenser and evaporator are clean, the engine fan and the blower fan are working good but this thing just wont cool good. 50° to 60° is as cold as I can get to come out the vents. oh yeah and the heater control valve is closing all the way. It cools better idling than revved up thats why I was wondering if the expansion valve could be messed up but still work a little bit. don't want to change it if I don't need to basically because it's not the easiest thing to get to and I don't want to waste the freon. Thoughts? Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/ Share on other sites More sharing options...
turckster Posted June 17, 2015 Share Posted June 17, 2015 Without gauges being hooked up and seeing what the pressures are while running its hard to tell whats going on. Generally, I like to see less than 30 psi on the low side and below 250 psi on the high side at an idle or slightly above-stationary. You want the engine fan to pull some air across the condenser while at or above idle to keep the high side under control-the more the better. If the low side is 35+ psi all the time then the expansion valve could be faulty. Air flow through the evaporator is crucial-make sure the evap. inlet side is clean and corrosion free. Make sure the compressor isn't cycling too often-either because excessive high side pressures (325-350+ psi), extremely low side pressure(less than 10 psi) or because of a faulty thermostatic switch. Here in west Texas, most truck a/c vent temps average 48-52 deg on a 95deg + day, using recirculate instead of fresh air. The system capacity for day cab is 3 lbs 134a and 3.5 lbs for sleeper cabs. 134a is less forgiving than r-12 on system capacities so make sure you use the correct amount. If you open the system then replace the dryer--no ifs, ands, or butts--they are cheap ($20 or less)-I've seen way too many desiccant bags contaminate a/c systems. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-293744 Share on other sites More sharing options...
jakebrake86 Posted June 17, 2015 Share Posted June 17, 2015 I think you just need to junk that CH and buy an R model! 1 Quote Jake Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-293758 Share on other sites More sharing options...
gumbiegumbie Posted June 17, 2015 Author Share Posted June 17, 2015 Well, my low side is high 20's to low 30's. my high side is 220 ish the compressor isn't cycling because the evaporator never gets cold enough for the thermostat to cycle the compressor. My vent temps are in the mid 50's so I guess it is working just as it should. I always run on recirculate because it's a dump truck and I'm always in mega dust. I guess mack just didn't put enough air conditioner on this thing. I guess it's time for new door seals and really dark window tint. If I can't make cold air I have to try to keep more hot air out but I really don't think thats the problem. Is there any tricks to make the evaporator colder? Different tonage expansion valve? Adjustable expansion valve? my old international had a bigger cab and the same size evaporator and got way colder. I've always thought that if you have to run an ac on high all the time it wasnt big enough for the application. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-293760 Share on other sites More sharing options...
turckster Posted June 18, 2015 Share Posted June 18, 2015 What I've seen on CH. CX and similar models (same cab basically) is most systems that had an issue was because of poor heat exchange across the evaporator due to corrosion on the evaporator fins and/or a plugged/dirty heater core. Because of its design, the evap is always getting dirty, even with a pre-filter it doesn't seem to help much. I kinda harp on that (air flow through the evap) because I see it so much.One of 2 things is happening, either the expansion valve is allowing slightly too much refrigerant through the evap. and its not able to absorb the heat inside the cab fast enough OR due to lack of good heat exchange (air flow or corrosion). When I check a/c system vent temps it is always at high speed, engine at 1000 rpm and on recirculate. Once the cab begins to cool down then you can turn down the blower motor speed. On road tests the vent temps usually were around the mid to upper 40's due to the ram air through the condenser and higher rpm. During the transition from R-12 to 1134a there were some CH models that vent temps between 50-55 was as good as it got. Your system should have vent temps in the mid to upper 40's on the road 1 Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-293801 Share on other sites More sharing options...
Popular Post Ezrider Posted June 18, 2015 Popular Post Share Posted June 18, 2015 cabin filters clean and evap cores clean. i run in dusty conditions too clean my cabin filters regularly and clean out the evap cores probably once every 6 months. also check for dirt buildup between your condenser and air to air. and between air to air and radiator. 3 Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-293805 Share on other sites More sharing options...
Keffer inc Posted July 8, 2015 Share Posted July 8, 2015 I have the same issue, I have a sleeper on mine though. Could it just be the heat from the roof? I have a dome light off right now and it feels like the devil is hiding up there. I'm going to try insulation on my truck, like for a house. On another note, anyone else having a wiring issue with the highest setting for the fan? My orange wire has melted two switches and when I try to jump it, it smokes and has a bad plastic burning smell. (Wire insulation I assume.) Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-296036 Share on other sites More sharing options...
Keffer inc Posted July 8, 2015 Share Posted July 8, 2015 Also, everything is clean and new on my truck except the expansion valve, but my coils inside the dash are also cold and sweating so I think everything with the ac is ok. Take your cover off and see, make sure it's not icing up. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-296037 Share on other sites More sharing options...
Dirtymilkman Posted July 9, 2015 Share Posted July 9, 2015 I heard truck cabs have less than a 2 r value Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-296114 Share on other sites More sharing options...
Keffer inc Posted July 9, 2015 Share Posted July 9, 2015 It's sad. I had my head liner out to run new speaker and aux wires for the FM radio. They only had some yellow foam squares stuck up there, leaving lots of bare metal still exposed. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-296141 Share on other sites More sharing options...
MACKS Posted July 9, 2015 Share Posted July 9, 2015 What I've seen on CH. CX and similar models (same cab basically) is most systems that had an issue was because of poor heat exchange across the evaporator due to corrosion on the evaporator fins and/or a plugged/dirty heater core. Because of its design, the evap is always getting dirty, even with a pre-filter it doesn't seem to help much. I kinda harp on that (air flow through the evap) because I see it so much. One of 2 things is happening, either the expansion valve is allowing slightly too much refrigerant through the evap. and its not able to absorb the heat inside the cab fast enough OR due to lack of good heat exchange (air flow or corrosion). When I check a/c system vent temps it is always at high speed, engine at 1000 rpm and on recirculate. Once the cab begins to cool down then you can turn down the blower motor speed. On road tests the vent temps usually were around the mid to upper 40's due to the ram air through the condenser and higher rpm. During the transition from R-12 to 1134a there were some CH models that vent temps between 50-55 was as good as it got. Your system should have vent temps in the mid to upper 40's on the roadYup,i just cleaned my evaporator for the first time on my 96 cl,what a difference.vent temps are now 44-45,also make sure the gasket in the cover is good or you wont pull the air across the evaporator 1 Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-296196 Share on other sites More sharing options...
Superhogult Posted June 7, 2020 Share Posted June 7, 2020 Hey all I have a 99 ch613 I’m trying to get the ac right on this thing. While at 1k rpms the evaporator will start to freeze up. The high side pressure is around 275 and the low side keeps dropping to around 10psi I just changed the expansion valve and dryer. Could I be looking at a plugged evaporator? Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452851 Share on other sites More sharing options...
1965 Posted June 7, 2020 Share Posted June 7, 2020 Make sure condenser is clean, aftercooler and radiator too. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452854 Share on other sites More sharing options...
Quickfarms Posted June 7, 2020 Share Posted June 7, 2020 A frozen evaporator is often caused by restricted air flow through the evaporatorMy good AC guys will hose the evaporator out of at least blow it out Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452855 Share on other sites More sharing options...
Superhogult Posted June 8, 2020 Share Posted June 8, 2020 What about the very low low side pressure? Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452883 Share on other sites More sharing options...
Superhogult Posted June 8, 2020 Share Posted June 8, 2020 The high side pressure climbs to 300 and the fan kicks on and the high side immediately drops to around 150psi. Isn’t the an indication of good air flow across the condenser? Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452884 Share on other sites More sharing options...
1965 Posted June 8, 2020 Share Posted June 8, 2020 46 minutes ago, Superhogult said: The high side pressure climbs to 300 and the fan kicks on and the high side immediately drops to around 150psi. Isn’t the an indication of good air flow across the condenser? Yes, didn’t say that in original post. High side seemed high to me thinking condenser dirty. 300 still is too high for fan to just kick in, my opinion. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452886 Share on other sites More sharing options...
Superhogult Posted June 8, 2020 Share Posted June 8, 2020 Ok I will check the radiator assembly as well as evap. Will the evap have some ice on it while running or should it be cold and wet? Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452888 Share on other sites More sharing options...
Superhogult Posted June 8, 2020 Share Posted June 8, 2020 Also before I put the expansion valve in the low side would drop down to 5 psi and the compressor would kick off. Now it runs none stop at 10-15 psi and has a wiggle in the gauge reading. Not sure if that means anything Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452889 Share on other sites More sharing options...
1965 Posted June 8, 2020 Share Posted June 8, 2020 Really I know enough to get by, I know everything needs to be clean, pull a good 30 minute vacuum. Would think low side should be around 25 to 30 & high from 250 to 280 range. Also thought engine fan was supposed to run any time air conditioner compressor was on. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452892 Share on other sites More sharing options...
hurstscrambler Posted June 8, 2020 Share Posted June 8, 2020 I know this sounds basic, but I’ve seen it before and it’s easy to check, pull the evap fan motor and make sure all the fan blades are perfectly clean. It sounds like you have an airflow issue. Sometimes they get a thin film of dust on them and it can greatly impact the air flow. You can even check the amperage draw before and after cleaning to see if it has an affect. As the fan moves more air it will draw more amperage. Andy Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452896 Share on other sites More sharing options...
Superhogult Posted June 8, 2020 Share Posted June 8, 2020 The blower has an issue cutting out and the relay getting very hot. I traced the issue to the selector switch on the hvac panel. But I have removed the blower and cleaned and tested the motor. The evap has a skin of ice on one side looking at it with the panel off. It doesn’t freeze up solid but it does form on the copper tubes on the side of it. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452901 Share on other sites More sharing options...
Superhogult Posted June 8, 2020 Share Posted June 8, 2020 From what I have experienced on other tractors the high side is in range but the low side pressure is very low. I usually see pressures around 40 psi. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452902 Share on other sites More sharing options...
Superhogult Posted June 8, 2020 Share Posted June 8, 2020 2 hours ago, 1965 said: Really I know enough to get by, I know everything needs to be clean, pull a good 30 minute vacuum. Would think low side should be around 25 to 30 & high from 250 to 280 range. Also thought engine fan was supposed to run any time air conditioner compressor was on. The fan will engage when the ac high pressure switch closes for condenser cooling. When pressure is below the 300 the fan will not be on. Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452903 Share on other sites More sharing options...
1965 Posted June 8, 2020 Share Posted June 8, 2020 Low side being low shows needs more Freon, needle jumping shows me it’s trying to take more. Evaporators freeze up for lots of things, low Freon, not enough air going through evaporator..... why did you replace dryer & expansion valve in the first place? Did you pull vacuum. Did system have failure? Did you flush system? How much Freon have you put in it? How much does your system hold? Quote Link to comment https://www.bigmacktrucks.com/topic/40532-ch613-ac-what-ac/#findComment-452904 Share on other sites More sharing options...
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