Superheat

[Steph9578]

In order to get superheat on a residential system do I need to have the wet bulb temp from inside the house at return. Or can I get the superheat without the wet bulb somehow. Could someone give me very easy directions on how to accomplish getting my superheat. I have the fieldpiece sman460 to help me but somethings not right and it’s probably me🤦*♂️

[Steph9578]

Does anyone know how to calculate superheat on a residential ac unit???

[beenthere]

((Indoor wetbulb times 3) minus outdoor temp, minus 80), divided by 2.

[Cool breeze 38]

Are you asking how do you check on site to see what the current superheat is?

[kdang]

Does anyone know how to calculate superheat on a residential ac unit???

Do you have an android smart phone? If so download the "HVAC Check & Charge apk" It's a pretty good apk https://www.apkmonk.com/app/com.emerson.checkncharge/

[ch4man]

In order to get superheat on a residential system do I need to have the wet bulb temp from inside the house at return. Or can I get the superheat without the wet bulb somehow. Could someone give me very easy directions on how to accomplish getting my superheat. I have the fieldpiece sman460 to help me but somethings not right and it’s probably me��*♂️

you need a WB reading taken from a spot that is the same as the evap sees. most of the time that means drilling a hole in the return large enough to get the probe of a digital psycrometer in.

you do have a digital psycrometer dont you? if not get one. in this field you need one.

now what is it your asking? target SH is different from actual measure SH.

beenthere gave the formula to get the target SH, there are many apps and cheat sheets also available as well to tell you what SH value you need at the conditions, at the time your charging a system.

wet bulb is not needed to find your actual measured SH (suction line pipe temperature minus low side saturation temperature)

get your post count up and apply for pro membership. you will get more in depth answers here

[Pres1227]

I got the sdp2s. Just used them yesterday on a piston system. I like em. Not too pricey either. And if your indoor and outdoor are relatively close together they can be synced with your sman. To give you target superheat. They also have enthalpy as a parameter so you can do actual capacity checks very easily. And %rh to check if air is bypassing coil!

[heatingelement]

((Indoor wetbulb times 3) minus outdoor temp, minus 80), divided by 2.

I have not seen this formula, is this actually uses to determine what your superheat should be? I usually go off the chart per manufacture. Assuming this is only for a fixed orifice?

[beenthere]

Yes, it actually determines your target SH. That formula has been floating around this site for many years. And it is only for fixed metering devices/pistons and cap tube systems.

[heatingelement]

Yes, it actually determines your target SH. That formula has been floating around this site for many years. And it is only for fixed metering devices/pistons and cap tube systems.

Good to know. Thanks. Learn something here just about everyday. Appreciate it everyone!

[Raehvac]

In order to get superheat on a residential system do I need to have the wet bulb temp from inside the house at return. Or can I get the superheat without the wet bulb somehow. Could someone give me very easy directions on how to accomplish getting my superheat. I have the fieldpiece sman460 to help me but somethings not right and it’s probably me🤦*♂️

There is a chart online that will tell you what your target superheat is. If you're in California than the CEC publishes one in the reference appendices.

You need your indoor wet-bulb and outdoor dry bulb using as they mentioned a psychrometer. Or you can use that $20 thermometer with a piece of wet shoelace on it.

To get your actual superheat you can take your line temp measurement at the suction line at the evaporator or on the suction line at the compressor (where the service valves are). Usually people take it at the service valves on the OD unit. The compressor superheat is the most important because that's where it matters. The evaporator superheat will give you an idea of how much heat loss is happening between the evaporator and the compressor. I do that for reference. Sometimes I replace the suction insulation as part of a maintenance if it needs only a little.

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[Colttblake]

Having a clamp on k type thermocouple is a must or at least a k type thermocouple (properly insulated) . And a digital psychrometer. I’m a tech in training going into my fourth year, (we are always training until we die) and I found out very quick that accuracy is good tools and we are only as good as those tools

[Core_d]

Having a clamp on k type thermocouple is a must or at least a k type thermocouple (properly insulated) . And a digital psychrometer. I’m a tech in training going into my fourth year, (we are always training until we die) and I found out very quick that accuracy is good tools and we are only as good as those tools

I got the uei thermocouple pipe clamps and found if i pressed on it, it would lower the temp by 4-7 degrees i ignored it the first few times and just used the temp while pressing on it. One time i got frustrated with it after i had to remove gas and just pitched it. Ive heard good things about the purple field piece clamps although the cost seems excessive for what it is. A regular ktype wire under the insulation has proven better for me and alot cheaper.

I really liked the apion thermistor clamps with the appion ions but that was about all i liked about them. When i get the new yellow jacket guages im gonna see if they work with them if im not crazy about the provided clamps


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[Colttblake]

I used the regular ole thermocouple and armaflex when I first starting learning about superheat, And I would practice on units at my house and while helping one of our service guys. Now I’m an official service technician and the clamps work great for me but it didn’t for my wallet haha I just got tired of ripping armaflex off and holding it to get a reading. But my baby is my field piece diagnostic psychrometer, and my Fieldpiece amp clamp. Saving currently for a set of digital gauges

[Steph9578]

Only buy fieldpiece hvac tools. You will thank me. I have been in this buisness for quite some time and fieldpiece is a well thought out and well built product.

[heatingelement]

Only buy fieldpiece hvac tools. You will thank me. I have been in this buisness for quite some time and fieldpiece is a well thought out and well built product.

You must have stock in fielpiece...

[Steph9578]

I wish.i just bought the sman460 and I love it

[3.14]

I have the fieldpiece wet bulb thermometer... it works well and I can plug it into my fieldpiece electric meter which gives me temp readings. I poke the sensor through the sock for checking dry bulb. Plus it’s really cheap.

https://www.ebay.com/i/361358362503?...422b5ffff740f5