Chiller not cooling very well

[justinm0424]

I have a current USA 1/3hp chiller and I don't believe it's working as well as it should. I noticed that there's a port on the chiller to refill the coolant. could I buy one of those car ac refill kits and use the gauge to check and see if it's low on coolant? I bought this used on ebay and I think it's about 2 years old so....

 

[Bebo77]

that may be the problem... are you running the recommended gph through the chiller?

 

[justinm0424]

no I thought this might be a problem. The recommended is around 7-800gph and i'm pushing around 500gph. I had about 1000gph going through it earlier but it didn't have and better performance and it actually cracked the water resovoir.

I only have a 40 gal tank with a 15 gal sump and with a 1/3hp chiller it takes about 7-10 mins to drop it .8 degrees. Does this seem about normal??

 

[andydavis141]

i would call current to find out what refrigerant is used for this model. from my experience on ebay you probally do need a refill, if its not your pump flow.

 

[Bebo77]

no i think you maybe correct in thinking that the coolant is running out.. contact the mfg and ask... thats your best bet

 

[andydavis141]

you don't want to chill it to fast. sounds like your way to big any way 1/3 hp for 55 total gallons? i have a 1/4 hp for 200+ gallons. your set up sound ok. the real test is if it maintains temp in hot weather.

 

[justinm0424]

I'm upgrading to a 150gal at the end of the month and I'm really concerned about having to keep the chiller on 24/7

 

[andydavis141]

congradulations!!!! thats awsome! find out what refrigerant it uses so if you have problems you can call a/c tech and have them refill also find out how much refrigerant it take to fill so you can tell tech if necessary. good luck i'm sure you'll do ok.

 

[mr. pluto]

flow on a 1/3 2606 prime chiller is 8~16 gpm
refrig is 134a
(imo) if it took 7~10 min. to drop the temp
nearly 1 degree it's working. you do not want the thing to cycle that fast, (premature wear on compressor) mine is on for at least 1.5 hrs.

 

[justinm0424]

I assumed it was 134a. Also 8gpm is 480gph and im right around there.

Do you all think I could use an auto refrigerant kit since they both use 134a? I've recharged ac on a car before and it seemed easy. I just blew a bunch of cash getting my new tank and accessories I'm broke and don't want to pay an ac guy to refill it if possible

 

[DarG]

Maybe im too late?

I dont think you have a problem. If it's dropping your 55 gallons for water nearly a degree in 7 minutes, it's probably working fine. I would not recharge the chiller. I had a 1/3 HP drop in on about 65-70 gallons a while back and it ran for 15-20 minutes and it was running fine.

In fact, I would set your temeperature differential to 2 degrees if it's now at 1 degree. You dont want that chiller running short cycles like that. 7 minutes is way too short of a cycle. It will shorten the life of the chiller.

 

[andydavis141]

i heard the same from my manufacture. you really don't wan't your compressor to wear out, i would have to agree with mr pluto & darg. but 134a refrigerant is 134a, you need to have a guage to know how much your putting in though, i don't think it's as easy as attaching a can and sqeezing. but i'm no expert. my controller starts at 1=.1,2=1.1,3=2.1,4=3.1,ect... i set mine at 4 deg difference and it starts the chiller when my tank water reaches 80.1 deg and cools it to 76.5-77.0 deg in approx 2hrs and kicks on when its about 3-4 times in a 24hr period and the garage temp is 100 deg that day, otherwise its only on once or twice a day between 80-95 deg.

 

[wlagarde]

It's almost assured it is R134a. I would be hesitant to charge the system unless you have a good idea what you are doing. To charge (while the unit isrunning and under load), you need to measure the refrigerant pressure on the high and low side of the system and measure the temperature of the suction line as it leaves the heat exchanger. Using this information you calculate what's called subcooling (if the unit uses a TXV) or superheat (if the unit uses an FOT) using a T/P (temperature/pressure) chart for R134a. Then you charge the system to the subcooling or superheat specification provided by the manufacturer.

 

[DarG]

My chiller runs for 45 minutes and even though it is set for a 1 degree differential, it actually cools closer to 2 degrees per cycle. I have it set for 76 degrees and I think it actually kicks on at something like 76.9 and off at 75.1 as you can watch a thermometer change 2 degress during the cycle. It's off for about an hour and a half (depending on house temp) and then back on for the 45 minutes.

I'm not sure how short of a cycle is too short but I'd bet that 7-8 minutes is way too short. Also, again, I dont think anything is wrong with the chiller if it's cooling nearly 1 degree in 7 - 8 minutes on 50 gallons.

Also, I was under the impression that you shouldn't go more than 2 degress with the differential as too much fluctuation is stressful on the fish and other organisms in our relatively tiny closed systems. This could be old wives tale by now though.

 

[wlagarde]

<a href=showthread.php?s=&postid=9619559#post9619559 target=_blank>Originally posted</a> by wlagarde
It's almost assured it is R134a. I would be hesitant to charge the system unless you have a good idea what you are doing. To charge (while the unit isrunning and under load), you need to measure the refrigerant pressure on the high and low side of the system and measure the temperature of the suction line as it leaves the heat exchanger. Using this information you calculate what's called subcooling (if the unit uses a TXV) or superheat (if the unit uses an FOT) using a T/P (temperature/pressure) chart for R134a. Then you charge the system to the subcooling or superheat specification provided by the manufacturer.

Just a clarification of my earlier post - You need the suction line temperature and pressure at the exit of the evaporator/heat exchanger for superheat and the high pressure line temperature and pressure as it leaves the condenser for subcooling. If you don't use the superheat (FOT - fixed orifice tube) or subcooling (TXV - thermal expansion valve) method then you are likely to overcharge the unit. A Google search combined with a phone call to the manufacturer should reveal all the info you need. You need a pressure gauge set and digital temperature probe to do the job. You can first check if the superheat or subcooling is within spec and if not (superheat will be high or subcooling low if undercharged) and then top off as necessary.

 

[ordy1]

<a href=showthread.php?s=&postid=9620399#post9620399 target=_blank>Originally posted</a> by wlagarde
Just a clarification of my earlier post - You need the suction line temperature and pressure at the exit of the evaporator/heat exchanger for superheat and the high pressure line temperature and pressure as it leaves the condenser for subcooling. If you don't use the superheat (FOT - fixed orifice tube) or subcooling (TXV - thermal expansion valve) method then you are likely to overcharge the unit. A Google search combined with a phone call to the manufacturer should reveal all the info you need. You need a pressure gauge set and digital temperature probe to do the job. You can first check if the superheat or subcooling is within spec and if not (superheat will be high or subcooling low if undercharged) and then top off as necessary.

Hi: Chances are probably good that if you were set to dump a can of 134a into your chiller you don't have a clue about Superheat, what a condenser is, or what a Thermostatic Expansion Valve (TXV) is.

It's portable. You can put it in the trunk of your car. Call some HVAC shops in your area and see if they will be so kind as to slap some guages on it and see if it has a sufficient charge. If it does and you still feel that it's not cooling correctly then the problem lies elsewhere and you'll still have a hard time finding the problem. Ask around and see what they'll charge you to check it out for you. It can't hurt.

Ordy

 

[wlagarde]

<a href=showthread.php?s=&postid=9632031#post9632031 target=_blank>Originally posted</a> by ordy1
Hi: Chances are probably good that if you were set to dump a can of 134a into your chiller you don't have a clue about Superheat, what a condenser is, or what a Thermostatic Expansion Valve (TXV) is.

It's portable. You can put it in the trunk of your car. Call some HVAC shops in your area and see if they will be so kind as to slap some guages on it and see if it has a sufficient charge. If it does and you still feel that it's not cooling correctly then the problem lies elsewhere and you'll still have a hard time finding the problem. Ask around and see what they'll charge you to check it out for you. It can't hurt.

Ordy

This is true. However, it's important to realize it takes more than slapping some gauges on to determine charge. Unfortunately, many HVAC guys do just this without determining subcooling/superheat - which is the only way of really determine proper charge (other than evacuating the system and charging to spec by weight).


So, although taking it to an HVAC place is a good idea, make sure it is a reputable place that will do the job right.