Suction meltaway relief valve open

[turbo50mike]

Got a service call on a Carrier condenser that wasn't working. Found the suction meltaway relief valve open, and the entire charge gone.

Condenser fans seem to be working, and everything else control wise seems to be working. Not sure how this let go, and never seen a suction one let loose before. No one was soldering near this thing or anything like that.

Wondering if any of you guys have seen the same, and what the apparent cause may be.

It's about a 20-ton condenser with a recrip compressor.

Thanks,
MJB

[chillerout1]

yes I have seen that happen on some older units probably have bad valves and compressor got hot and released refrigerant some did not have over temp cut outs on them especially on rebuilt compressors or some one bypassed or removed them

[turbo50mike]

The unit is not old at all (maybe 5 years)...And these reliefs were not on the compressor, but about 2 feet away on the suction piping. Carrier says the suction one melts at 176 deg F, liquid at 210 deg F.

Can't see how the suction got that hot, that far away.

Maybe just a faulty plug? Just didn't know if there was a reason that the suctions melt? Never had one fail before.

Compressor still seems good, but we'll see.

[chillerout1]

dont think they put the overtemp protector on them any more 06s but yes they will get that hot on the suction with bad valves

[turbo50mike]

dont think they put the overtemp protector on them any more 06s but yes they will get that hot on the suction with bad valves

But we'd see some indication of that by the pressures, no?

[Dallas Duster]

But we'd see some indication of that by the pressures, no?

And what pressures would that be?

[turbo50mike]

And what pressures would that be?

Suction pressures. I would imagine that we would see an increase in suction pressures/temperature if the valves were shot. How else would it melt that 176 deg F plug on the suction line?

[beau2cunningham]

I would imagine faulty capacity control valve,unloader

[chillerout1]

yes you would see higher than normal pressures

[deux]

I hear UV light from the sun breaks them down. No more ozone layer where you live.

HAHAHAHAHAHa Now to be serious.

I had one let go in a fire once. Good thing the R22 put out the fire and saved the building.
I would suspect you just have a bad one, they are just super soft solder. Bad joint. I have done a few that just let go for no reason. Was this an Aquasnap by chance?

[just_opinion]

I have them idiotic plug. I normally take them out. And use some thing else to protect the system or compressor.

I cannot believe that EPA still allow carrier to use this type of method to relief 100 of lbs of R-22 in to the atmosphere. I guess they got money to buy the EPA.

[VTP99]

Got a model number for that Carrier ?

[Dallas Duster]

I have them idiotic plug. I normally take them out. And use some thing else to protect the system or compressor.

I cannot believe that EPA still allow carrier to use this type of method to relief 100 of lbs of R-22 in to the atmosphere. I guess they got money to buy the EPA.

What type of alternative do you use?

[uniservice]

On commercial fishing boats I use a PRV piped to the suction side of the compressor. Install a flow switch and a sight glass. Hook the flow switch up to an alarm, and then the engineer is notified of a problem without the loss of refrigerant. Found one, one time that was piped in a green garden hose to the air inlet of the auxillary engine. If the prv opened due to failure of the condenser pump, the refrigerant flowed into the air intake of the engine, and caused pretty white smoke to come out of the exhaust pipe on deck, notifying the operator of a problem in the engine room. LOL

[just_opinion]

What type of alternative do you use?

For the suction line to get that hot to melt the soft-plug, the discharge line must be VERY hot too. So use temp switch.

Also, if the soft-plug is melted at (someone claimed) 160 degrees F, then why not use a temperature switch. Rather than releasing 100 lbs of R-22, which EPA said depleting the ozone, into the sky.

Carrier uses this method on other types of applications too, such as residential units with reciprocated compressor, today new scroll compressor, today chiller with scroll. In fact they use this on all of their applications.

Who cares, I don't own these machine. I work on them.

[VTP99]

Who cares, I don't own these machine. I work on them.

My guess is that the plug is full proof and mechanical controls could fail resulting in a worse case scenario

[Dallas Duster]

My guess is that the plug is full proof and mechanical controls could fail resulting in a worse case scenario

Or be bypassed.

[Tommy1010]

Had 2 ...one last year on suction line.

It was a Carrier water cooled package unit.

Couldnt believe the same thing..SUCTION THAT HOT...???

Ended up with a cracked condenser and water breach...Hooked nitro and water shot out like a hydrant!! Not sure which happened first in that case..the water breach or the heating of the system...CHICKEN OR THE EGG?

Last month i had a aircooled rooftop package...LL thermal plug blew open.

Ended up with a grounded compressor.

This was a result of a bad condenser fan motor and bad high pressure switch.

I have no idea why have one on the suction line. Matter fact these old 50BR units dont have any on the LL, only suction....DONT ASK CUZ I CANT ANSWER.