HVAC guy came out today.... "working good", but still not as cool as it was in past??

[blitz99]

ok, i got ripped for "price shopping" earlier this week so i contacted my realtor and he gave me a number to a local company (family owned and operated for over 20 years)... any chance you folks can tell me what this stuff means???

and on a 90 degree day what should i expect of my AC unit? should it be able to cool to 65? 70? it's a lennox built in 98, and it's bigger than the neighbors

anyway, dude came out and checked everything today... my readings are:

condenser = clean
contactor= good/fair
motor amp draw rated 1.1 actual .8
compressor amp draw rated 10.1 actual 6.96
refrig level ok
capacitors ok
electrical connections ok
disconnect ok
condition of fuses ok
coil resistance on contactor 13.2 ohms
valves with pump down test ok
temp out at reg 57 degrees (83 outside)
no refrigerant added

ref. press S.L. 72 (what does this mean???) l.l. 195psi (huh???), ambiant temp 78 degrees, amp draws and contactor ok, checked temp at registers = 57 degrees, system works good at this time.

[RoBoTeq]

Without refrigerant line temperatures it kinda says a whole lot of nothing.

The compressor is working and heat transfer is taking place is about all we can determine for certain.

Need to know what the metering method is and the temperatures of the liquid line (LL) and suction line (SL)

[blitz99]

how do i know if he even checked that? is that what the double guage thing was that was hooked up to the two lines?

[Special Ed]

Sounds good to me!

So.... I take it you don't trust the guy that came out?

[BaldLoonie]

Most equipment is sized for mid 70s on the hottest days. On a 90 degree day, 65 to 70 would require a grossly oversized unit.

Seems like a very thorough check to me.

[blitz99]

cool... i think i may be confused about temp settings from last year.. i thought i cooled to 68 on hot days, but i KNOW i heat to 68 in winter so maybe i only cooled to 75... oh well, my stuff is working, i'm happy.

[deanoac]

I am in agreement with Ro Bo. With out a few more details no professional can make a concise diagnois, it would be like checking the air in one car tire with a guage but just looking at the other three as to Visually determine they are correctly inflated! Why doesnt the tech just grab the suction line to see if it is Beer Can Cold it would have told him more !

[RoBoTeq]

Neither temperatures or pressures alone tell us anything absolute. We really need to know the temperature/pressure relationship in the form of superheat and subcooling to really tell what is going on with a system.

[blitz99]

and how do i get that?

because as much as i want to think my system is fine... it's keeping the temp in the house the same, but not really lowering it... the thing seems to be running constantly. i just spent cash on one guy and cannot afford to do this again.

[RoBoTeq]

You don't get it, you get your contractor to get it.

Tell your contractor that you need to know;
Superheat
Subcooling
Delta-t of evaporator, particularly dry bulb but some here cannot seem to live without wet bulb so be sure your contractor gets that data also.

If you want us to second guess your contractor, we need to know your contractor is looking for the right things and knows what to do with that information.

Honestly, the information you gave on your system sounds more like it was obtained by an electrician with a set of gauges and pocket thermometer.

[blitz99]

it was an AC inspection and clean that he did... i paid double what my coupons for other companies said and got the same service (seemingly).

[Mr Bill]

Originally posted by blitz99
it was an AC inspection and clean that he did... i paid double what my coupons for other companies said and got the same service (seemingly).

Lol! you would have paid quadruple if you would have called one of those "coupon companies"
you hand them the coupon at the door, grab them ankles and hold on, but some do offer KY for free with the coupon look on the back and see if yours do.

[dnt]

Now these boys were using the gauge measurements to check your unit charge there are several other methods that work just as well (INACCURATELY) to check your unit charge. NO 1 The ole gifted finger technique were the tech charges to get the suction line cold,about like the temp of a BUD lite brew fresh outta the cooler NO 2 The ole compressor amp draw, charge untill compressor amp draw matches nameplate NO 3 the ole get the condensor saturation temp 35f above outdoor ambient or any number of other crazy methods. If they did not check airflow CFM and FPM and did not get superheat and subcooling numbers you wasted your money IMO Most companies will not do that seems to be industry standard it just cost to much and there is nom consumer awareness for the need so anyone that does it and trys to get paid does not operate very long on residential the ground actually washes away right underneath his feet by the undercutters that do little more than glance at a system and fill out a sheet LOL

[blitz99]

so, are you saying i need to request certain checks? like the subheating/subcooling or they will not perform the test? if so, how in the world is someone who knows NOTHING (me and every other typical consumer) about HVAC supposed to know to ask this?

[HVAC Pro]

Looks like a 21° delta. That's assuming the 78 figure is RAT and 57 is SAT Looks like ODA is 83. It's possible that the system is undersized.

[RoBoTeq]

Why not call the company that did the service and ask them the questions you are asking us? They may have the superheat and subcooling numbers on hand.

However, if the company did not do any pressure/temperature relationship testing you have a right to ask them to recheck your system and give you that information.

[HVAC Pro]

I agree with RoBoTeq. You would hope that everyone checks superheat & or subcooling. But we all know that probably at least 4 out of 5 don't. Unfortunately.