AC troubleshooting issue

[WCarp]

Need help troubleshooting a NH Boomer 3050 AC system using R134a. The Mastercool gauges read on low side 71 psi and high side was 112 psi. Second time I tested it, low was 71.5 psi and high was approx. 127 psi. Ambient temp was approx. 85 degrees F and RH was low. The air duct outlet temp was 51.5 degrees F. The compressor never cycled and the evaporator and condenser are clean. It has an expansion valve.

According to the NH Service Manual, at approx. 85 degrees F, the low side pressure should be around 13–14 psi and the high side pressure should be 159–179.

Could you comment? Thanks.

 

[Roger in Iowa]

You are getting a 35 degree drop over ambient. 40 is usually max.
Low side is . Is fan belt slipping and causing high? Condensor and radiator have to be clean. Also area between them.

 

[joeysmith]

You definitely do not want your low side at 13/14 psi
That puts you at a 14 degree coil that will freeze up

Your compression ratio is pretty low at 1.7 which leads to the belt or clutch slipping as stated or the compressor may be on its way out

 

[joeysmith]

Your high side is pretty low as well for that ambient which points towards your compressor or compressor drive issue
Or possibly a metering device stuck open (which in my experience is fairly rare. They tend to stick closed which will cause high head pressure an low suction pressure )

 

[Stan Coryell]

Your high side is pretty low as well for that ambient which points towards your compressor or compressor drive issue
Or possibly a metering device stuck open (which in my experience is fairly rare. They tend to stick closed which will cause high head pressure an low suction pressure )

View attachment 165167

I'd expect 40/ 200?

Do you have any background on the A/C system? Was it working a few weeks ago? Any stop leak in the system?

I agree most TX valves fail closed. Maybe this one fails open?

The suction is awfully high. That would point me to the TX. Can you warm it up with a hot rag or hairdryer and see if the suction drops?

If the condition of the system is unknown, it might be worth it to replace the TX, draw it down to 250 microns, and recharge by weight.

 

[Powered By IH]

Need help troubleshooting a NH Boomer 3050 AC system using R134a. The Mastercool gauges read on low side 71 psi and high side was 112 psi. Second time I tested it, low was 71.5 psi and high was approx. 127 psi. Ambient temp was approx. 85 degrees F and RH was low. The air duct outlet temp was 51.5 degrees F. The compressor never cycled and the evaporator and condenser are clean. It has an expansion valve.

According to the NH Service Manual, at approx. 85 degrees F, the low side pressure should be around 13–14 psi and the high side pressure should be 159–179.

Could you comment? Thanks.

What was your static pressure on your gauges before starting?

 

[NoDakInMN]

Higher than normal suction pressure and lower than normal discharge pressure, with the belt properly tensioned and adequate rpms, is indicative that you have valve problems in the compressor and it needs to be replaced. If you have service valves on the compressor, front seat the suction service valve (blocking off flow to the compressor but leaving the access port open to the compressor inlet) and run the compressor. You should be able to pull a slight vacuum in this condition if the compressor valves are good, if not, your suction valves are leaking. This is usually caused by liquid flood back to the compressor. Unlike vapor, liquid does not compress and the valves get broken.

 

[Ray,IN]

FWIW, this is the best A/C service manual I've ever read. https://btrac.com/wp-content/uploads/2025/04/Service-Manual-Revision-1-2011.pdf

 

[joeysmith]

FWIW, this is the best A/C service manual I've ever read. https://media.toro.com/servicemanuals/Badger_SM.pdf

Thats pretty good

Bookmarked

 

[Ray,IN]

Thats pretty good

Bookmarked

I recommend downloading the manual. It seems Badger reworks their website often and I have to hunt for the manual again and again. I cannot find it on their website tonight.

 

[joeysmith]

I recommend downloading the manual. It seems Badger reworks their website often and I have to hunt for the manual again and again. I cannot find it on their website tonight.

Back in my mechanic days I use to despise working on air-conditioning in equipment an trucks.
Nobody taught the refergeration cycle really.


After getting into hvac many years ago an actually being taught the refergeration cycle it all became crystal clear.


Ye ole light bulb moment

 

[matthies]

Replaced expansion valve, stuck open.

 

[Stan Coryell]

I'm glad you got it fixed!

 

[WCarp]

You are getting a 35 degree drop over ambient. 40 is usually max.
Low side is . Is fan belt slipping and causing high? Condensor and radiator have to be clean. Also area between them.

The compressor belt is tight.

 

[joeysmith]

The compressor belt is tight.

Whats yer numbers now?

 

[WCarp]

I'd expect 40/ 200?

Do you have any background on the A/C system? Was it working a few weeks ago? Any stop leak in the system?

I agree most TX valves fail closed. Maybe this one fails open?

The suction is awfully high. That would point me to the TX. Can you warm it up with a hot rag or hairdryer and see if the suction drops?

If the condition of the system is unknown, it might be worth it to replace the TX, draw it down to 250 microns, and recharge by weight.

I have not put any gauges on it for several years. As far as I know it was working okay then. There is no stop leak in the system. The expansion value is under the cab cover so at this time it isn't easy to access.

 

[WCarp]

What was your static pressure on your gauges before starting?

The static pressure was approximately 100 psi.

 

[WCarp]

FWIW, this is the best A/C service manual I've ever read. https://btrac.com/wp-content/uploads/2025/04/Service-Manual-Revision-1-2011.pdf

Thanks.

 

[WCarp]

Whats yer numbers now?

I haven't tried checking lately.