pressure discrepancy - heat pump

[narfhead22]

ok so a guy i work with (seriously, a guy i work with, not myself haha) was talking to me about an issue he was trying to diagnose. went to a heat pump call for a freezing condenser coil. pressure was low, so he added freon, then checked it in heating and cooling modes, and found a big discrepancy. pressure was too high in one and too low in the other mode (not sure which). a few people in the office think it is the reversing valve. the others think the filter dryer needs to be replaced. what would be a good way to find out? reasoning tells me that the bes idea is to first replace the dryer since it is a far less expensive and less labor intensive part to replace. but it would be better to be able to diagnose it more accurately before doing anything, especially since the unit is out of warranty. if a reversing valve is sticking, wouldn't the "swoosh" sound be absent? or have clicks or something? thanks in advance.

[Crazy4thenucks]

You need to know what the superheat and subcooling temperatures are...without those, your just guessing and replacing parts. I bet you its not the filter dryer, but the temperature difference across it will let you know that.

[m-cooling]

You need to know what the superheat and subcooling temperatures are...without those, your just guessing and replacing parts. I bet you its not the filter dryer, but by taking the temperature difference across it, will let you know.

Yes, more info. is needed to know whats wrong.
Could be neither of the two things he mentioned.
We would need pressures and temp. at different locations to help you.

[snooked321]

could be that metering thingy:LOL:

[lynn comstock]

Could be airflow, yadda, yadda.

[bmathews]

I doubt it is the filter dryer being clogged. The only time I've had a clogged filter dryer is when the tenant of a house, who was a minister. Had a member of his congregation out who did a/c to check the system out and he would give him a couple of bucks to help him out. He was down and out. Somehow this guy got lots and lots of dirt into the system and told the guy/landlord he needed a new system. Ungodly amount of dirt into it. We got called out and cleaned things up. I had to go back about 6 months later and change out 2 clogged filter dryers.

[Shophound]

could be that metering thingy:LOL:


Plus One...

For the OP: Folks can talk about "what it might be" until the cows come home. Until there's real data gathered, that's all it is...talk.

[Stamas]

Plus One...

For the OP: Folks can talk about "what it might be" until the cows come home. Until there's real data gathered, that's all it is...talk.


In other word, see Sonic's threads.:grin2:

[just_opinion]

ok so a guy i work with (seriously, a guy i work with, not myself haha) was talking to me about an issue he was trying to diagnose. went to a heat pump call for a freezing condenser coil. pressure was low, so he added freon, then checked it in heating and cooling modes, and found a big discrepancy. pressure was too high in one and too low in the other mode (not sure which). a few people in the office think it is the reversing valve. the others think the filter dryer needs to be replaced. what would be a good way to find out? reasoning tells me that the bes idea is to first replace the dryer since it is a far less expensive and less labor intensive part to replace. but it would be better to be able to diagnose it more accurately before doing anything, especially since the unit is out of warranty. if a reversing valve is sticking, wouldn't the "swoosh" sound be absent? or have clicks or something? thanks in advance.

It is best that your company call a proffesional out to diagnose the problem. Who knows - you may and your company can learn some too.

[dandyme]

what were operating conditions?

narf...............pay attention at this point, if you stick around here and advance, these are going to be pieces of info you will need to bring to the table the first time, getting info to try and solve an issue should not be like pulling hens teeth

[Shophound]

In other word, see Sonic's threads.:grin2:

LOL! :LOL:

[gzone53]

check line temp before and after dryer , temp difference means pressure difference.

[lynn comstock]

check line temp before and after dryer , temp difference means pressure difference.I never saw that work on a cap tube system.

[narfhead22]

what were operating conditions?

narf...............pay attention at this point, if you stick around here and advance, these are going to be pieces of info you will need to bring to the table the first time, getting info to try and solve an issue should not be like pulling hens teeth

sorry about that. those are the only details i have, unfortunately. like i said, this was something another guy at my company ran into. i wasn't there to gather all the info. i understand that with that amount of info, nobody is going to be able to diagnose it, especially not over the internet. i was simply trying to get some other ideas from you guys about what could possibly be the issue, given the info. sort of like a "you might want to check ________" type thing.

[patrick]

It could be the coil is dirty, the fan is not blowing enough air, the outdor metering device isn't working properly, the refrigerant charge isnt correct, something with the defrost isnt working correctly, the filter dryer is plugged, the reversing valve isn't working correctly, the discharge out of the condenser is being short cycled. Also the unit could be working properly, heat pump coils do frost over. If it is freezing to the point that it blocks airflow there is a problem.

Someone needs to check the pressures, superheat, subcool and liquid pressure if possible when the outdoor coil has been defrosted 100%.