However specs for these two units do not state “nominal” temperature. I keep adding refrigerant till I get a 20 degree difference. Upon placing my gauges on the unit, I noticed the pressures were normal (75/210). Four our purposes we will look at most efficient units from Fujitsu and Mitsubishi (Fujitsu 12RLS3YH & Mitsubishi MZ-FH12NAH) in 12K BTU capacity , which is enough for 400-500 sq. I would not expect it to be ruined by that fact alone. That’s what makes our innovative, super-efficient heat pumps a great choice for families seeking a versatile heating and cooling … Typically, heat pumps have cooling operating temperature range of 15°F to 115°F (-10°C to 46°C). I'd check the thermostat position - it may be in a location that does not properly sense room temperature, such as in direct sunlight. Note that if only some of your ducts have poor air flow then it's not a TEV problem since an iced coil would reduce the air flow into ALL of the supply ducts. 68.5 f nxt week hes going to temove coil to see if anything is disconnected. Sorry that's too broad a question to even understand where to begin. The pressures on our home AC system (R22) seem fine when operating: suction line 73psi, liquid line 233 psi. Help please? I have a older unit, central air unit inside the condo. Your body temperature is around 98.6°F (everyone’s body temperature is slightly different, but that’s the average). 2 story house then goes all the way across aprox 40-45 ft. Then down to furnace. I'm familiar with this line frosting or freezing at this point, but have never seen one get hot and melt insulation. Maintaining Your Heat Pump Turn the power off on your unit before cleaning it in the spring. Now let’s see when and where heat pumps are and are not effective: There are all kinds of ductless units, which primarily offer better efficiency and quality, based on how much ductless systems cost. I'm sorry Phil but I'm just baffled by your question. We have a dual air conditioning unit and when we shut both levels to the off position it still sounds like air is blowing. But the efficiency of the system is affected by outdoor air temperature. At the time the repair technician said my air handler speed was two high, and set it on low. The furnace kicks in for only the coldest months. He did not note the model numbers but did note they were manufactured in 2004 and said R-22.On the 3-ton unit the supply air temp was 60 degrees and the return was 72 and he said this is out of range and is a problem, but did not indicate if this just means the unit is low on freon, has a leak, coils and filters need cleaning, or the unit is at the end of its expected life and should be replaced.On the 2-ton unit the supply air temp was 61 and return was 77, again he noted this was out of range.Can anyone shed some light on what these numbers mean, what they should be on a properly working system, and does it sounds like these units need to be replaced or just serviced?Thanks,Carl. My buddy replaced it and we left the existing furnace. Some diagnostics for an air conditioner that won't stop running are over at, inspectapedia.com/heat/Furnace_Fan_Wont_Stop.php. Thanks, Chris - CK 7/14/12. But at an outside temperature of 15 degrees F, no one would expect the air conditioner to be operated - doing so risks damage. I replaced the batteries in the thermostat twice, I blow out with can air to clean dust, no change. of 72F and the indoor temp around the same and I turn the thermostate to 70F the compressor will not run only the fan. Nate I do not know a factual answer to your operating temperature range question, it would need to be answered by the specific manufacturer of the A/C system. See RATED COOLING CAPACITYof air conditioning equipment if the system seems to be working but is inadequate to cool your building. In fact, millions of GHP systems are already heating and cooling homes and businesses worldwide, and that includes all 50 U.S. states. Watch out: do not turn on an un-known air conditioner or heat pump system in cold weather if you don't know about the temperature rating of your outdoor A/C system (or heat pump system) and if you have not checked with your HVAC service technician. In hotter outdoor air the compressor/condenser has to work harder, and perhaps longer to condense the refirgerant back to a liquid. CK thanks for the interesting question. A heat pump is very simple once you understand the basic concept. Not sure you have a problem; Nor did you make clear exactly where you took your measurements. Designed for year-round comfort, a heat pump keeps you cool by drawing heat from your home on warm days and drawing heat from the outside air to keep you warm on cool days. Changed out blower and coil. The most it had come down to was 52. i need to cool a very warm room all year round. How to calculate evaporator tempature - Erhan. Problem: Rubber insulation on suction line from evaporator to about 15 to 18 inches down the line (towards compressor)has melted from heat. JD:the answer is an OPINION as I don't think there is a single right answer: Often I like running the A/C fan continuously to improve air/dust filtration and give more even indoor temperatures; I recently replaced a fan relay. However, when the temperature drops below the heat pump's ability to operate as efficiently as the gas furnace, the gas furnace will take over until the temperature rises enough for the heat pump to operate more efficiently. Now, lets answer the question whether heat pumps are EFFECTIVE in low temps. Now the question is – are these units effective at such low temperatures? On moving the system the whole thing will be emptied and recharged anew, which might then look as if it were the move rather than the charge that fixed matters. Pete, Yes I think you're quite right. If your system has good air flow but temperatures are too warm I suspect lost refrigerant or a bad control. that can result in low side pressure being abnormally low, uneven refrigerant metering; a blob of oil or dirt traveling in the system easily blocks a cap tube.Is there a drier that could be clogged or has the unit never been opened ?Is the blower fan itself dirty? That's because building and environmental conditions vary so widely that the temperature of the return air entering the cooling system also varies widely from time to time.A cooling system generally produces a rather constant temperature drop across the cooling coil, so long as the air flow rate stays unchanged. This question was posted originally at DIAGNOSTIC GUIDES A/C / HEAT PUMP. My air blowing out of my vents is aaround 80 degrees. If you plan to have a large Solar PV array installed on your roof, then going with a Heat Pump is a no brainer! Now, after the fan relay has been replaced the register cool temp has sometimes hit 56.1f. Adjust your thermostat – there are two things you need to do with your thermostat to switch your heat pump to cooling mode. But I don't think I can give a straight answer evaluating an 8 degF drop in cool air output temperature after getting a fan relay replaced. We check the unit current and its ok, so we believe the charge is also ok. We check other possible causes, like distorted coils fins, dirt, obstructions and blower speed and they seem to be all ok. What do you think should i do more? If your air conditioning or heat pump system has lost its cooling capacity or won't start see REPAIR GUIDE for AIR CONDITIONERS. When the system is off, the pressure equalizes to 115psi. (But we'd want to see the efficiency operating curve and operating cost data too.) Basically, Central Heat Pumps are only effective in warmer climates (Regions 3, 4 and 5 on the Climate Region Map above). Lines coming from condensor go up aprox 20 ft. They say a minimum of 14. So know I don't know what to think as two technicians from same company had opposite recommendations. To explain what we mean, first we’ll need to look at how a heat pump works and why it needs backup heat. temperature difference between intake and suppy was 13 degrees it should be 15 - 20 degrees,how do i fix - Brian 8/23/12. At higher outdoor temperatures the system may not be able to produce the same cooling capacity. Something that slows the air rate may cause a greater temperature drop - not always desirable, and vice versa.So if the weather or your home were hotter when you made the first measurement than when you made the second, that condition alone could explain the change that you saw. PTACs are usually found in hotels/motels, where they do excellent job, but that is a topic for another article, so here we will not review them. (July 6, 2014) Anonymous said:my johnstone central air systems runs continuously. I won't go with the idea that the thermostat should be set in a way to avoid the compressor running continously because before the trouble begun the unit has been running almost continously for 8hours for the last several years and there was no occurance of ice/frost build-up. We have no relationship with advertisers, products, or services discussed at this website. - J Flores 8/11/12, JYou made a good guess. Air from vent. When he arrived he said everything check out, But he said the fan was set to low. Did I put too much Freon? The outside temp is apporx 15 degrees, would this have anything to do with it? Air conditioner temperatures that are too high or too low can indicate I'm wondering if the compressor has been damaged but would rather not replace it as a means of troubleshooting. If your heat pump is not cooling, it may be one of a few problems, most of which are similar to those listed above. What's up with that? However, even at the coldest limit, Fujitsu is rated at 98% of its nominal capacity, whereas Mitsubishi would only provide 73% of its rated capacity, and 37% less heating that it’s Fujitsu counterpart. Can you help me pelase ? I recently had my traine system repair under warranty work. But heat pumps also have one huge benefit that furnaces lack: It allowed the temp of coolant to drop to 42. i replaced the control board and they gave me a whiterodgers Single Stage HSI Integrated Furnace Control Kit ... now this happin in winter time .. before this i had around 58F output on AC.. now iam upto 66F output .. on the AC uint inside home .. the small line is cold . In cooling mode, ALL heat pumps are very efficient, and work from northern Canada all the way south to Central America. I have a problem. Earl. hello.. wondering i have a 7 to 8 year old lennox hvac. Outdoor compressor/condenser units are designed for outdoor weather exposure; but that's not to say that your particular unit is designed for outdoor use in cold weather. I typically get the units I work on down to 59 degrees coming out of the air vent, s. The 16 degrees mentioned is what I consider bare minimum. If you used to set it to 68, turn it to 58. A heat pump is part of a heating and cooling system and is installed outside your home. When the house is empty for an extended amount of time and at night, it is a good idea to lower the temperature to 58 to 62 degrees. Red gauge 370 degrees. per say ? Also, most AC units last 10-14 years, although I worked on an oldie that was over 30 years old. it cools the house down fine but it won't cycle. Different manufacturers specify different low limits. stayin on the low stage? Or skip directly to AIR FLOW TOO WEAK at InspectApedia.com. - Pete 6/27/12. Emerson Sensi ST55 Wi-Fi Smart Thermostat. Our differential reads at 12 which does not meet state standards for a home inspection. With a heat pump, you can use the same system to cool your home that you do to heat your home, and heat pumps can save energy costs by 30 to 40 percent when it comes to heating your home during the winter, says Pat Cray, owner of South Hills Electric in Pittsburgh..