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  1. Replies
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    Right, I should have been more clear. If the...

    Right, I should have been more clear. If the units are rated for 208/230V you can use 2 legs of a 3 phase service, otherwise you would be undervoltage since the 2 120 legs will get you 208V not 230V.
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    Yes, there is 240V/3Ph, as we refer to it,...

    Yes, there is 240V/3Ph, as we refer to it, country ass electric, but my point was that if he does have 208/230V/3Ph power, you can't run a standard 2 pole 240V condensing unit.
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    The 1Ph and 3Ph units with equal hp motors will...

    The 1Ph and 3Ph units with equal hp motors will draw the same power. The real advantage of 3Ph is for the motor, they like the smoother power curve and should last longer with everything else equal....
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    Usually the boiler makeup is attached at the air...

    Usually the boiler makeup is attached at the air separator so the makeup water can run through it before entering the system. The only "wrong" place for an expansion tank is at the pump discharge...
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    Agree with the above poster. You want 50 cfm in...

    Agree with the above poster. You want 50 cfm in bathrooms and 100-150 cfm in bathrooms with showers for moisture control. What I have in my house and recommend is to wire the exhaust with the lights...
  6. You don't use a bypass damper on Infinity systems...

    You don't use a bypass damper on Infinity systems since they are variable speed. If you use a bypass it will not like it and constantly search for the setpoint. You MUST use an Infinity zone...
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    IMC should have a new code in 2009 as far as I...

    IMC should have a new code in 2009 as far as I know. I've never had the AHJ ding me on OA when I use DCV, even in Chicago at permit reviews you just have to explain your methodology. Obviously, I too...
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    No you don't. It is at the engineer's discretion...

    No you don't. It is at the engineer's discretion to determine the appropriate people load. The IMC explicitly states that. ASHRAE also allows for a 50% reduction in people if the space is not...
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    I don't understand your argument here. I am just...

    I don't understand your argument here. I am just advising to use some common sense instead of blindly following codes.
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    If you have a 400 sqft reception area with 5...

    If you have a 400 sqft reception area with 5 chairs in it, I don't think you have to provide air for 20 people. I think that is pretty straightforward.
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    Thermal comfort & exhaust is in ASHRAE...

    Thermal comfort & exhaust is in ASHRAE fundamentals. For occupancy you would want to look in the Building Code & the Mechanical code. Personally I would use judgment for both, e.g. a lobby is listed...
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    You use the 5 psi with a 3.5psi drop table in the...

    You use the 5 psi with a 3.5psi drop table in the IFGC. You would then regulate the pressure to 7"w.c. at the unit. At least that is how I would do it.
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    Are you nuts? An unoccupied utility room needs no...

    Are you nuts? An unoccupied utility room needs no ventilation and the code agrees. ASHRAE allows up to a max of 5,000 ppm of CO2 in an 8 hour period. Two persons in a room for maintenance would take...
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    No recirculation of bathroom air. Section 403 of...

    No recirculation of bathroom air. Section 403 of the IMC. For residential, the code requires either 20 cfm of continuous exhaust or 50 cfm of intermittent exhaust. I do believe that there is an...
  15. Rules of thumb are 2.4GPM / ton on the chilled...

    Rules of thumb are 2.4GPM / ton on the chilled water side and 3GPM / ton on the cooling tower side.
  16. Design temp for Chicago is -10 and we've hit it...

    Design temp for Chicago is -10 and we've hit it more than once this year.
  17. Sorry :p typing too fast, yes that is what I...

    Sorry :p typing too fast, yes that is what I meant OA > HC > CC.

    As far as the preferred setup with PH > CC > HC, I can't say I've ever seen a unit installed with this configuration. I don't see...
  18. Cooling coil is upstream of the heating coil for...

    Cooling coil is upstream of the heating coil for freeze protection as well as dehumidification, I always call for my units to be oriented that way even if there is no application for...
  19. Stats, valves and pumps fail, you also have...

    Stats, valves and pumps fail, you also have damper leakage when the unit is off. Water + OA <32 == freeze. You have to prepare for that. Chilled water coils should be drained in the winter months...
  20. The FLA is 53 but what is the LRA? Since you seem...

    The FLA is 53 but what is the LRA? Since you seem to be pretty sure that everything is installed correctly and all the wiring looks fine, it definitely sounds like the fuse is too small. Most motors...
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    7 day programmable tstat with 55/85 setback is...

    7 day programmable tstat with 55/85 setback is required by the energy code for any non-residential job.
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    Your local McQuay guy should be able to tell what...

    Your local McQuay guy should be able to tell what was originally in there since you got the serial number. I'd give them a call.
  23. Replies
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    I take it you don't work with JCI often then:p

    I take it you don't work with JCI often then:p
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    I'll throw some numbers out there since you don't...

    I'll throw some numbers out there since you don't want to :D

    IMC says that retail stores should have 0.3 cfm / sqft of outside air. If you have a 1500 sqft store that requires 450cfm of outside...
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    Granted he didn't do a load calc, but he is...

    Granted he didn't do a load calc, but he is probably right. Old furnaces were only about 70% efficient, so your BTU output was most likely around 70,000 BTU's and a new 90% 60,000 BTU furnace would...
  26. The system can work with a small zone, but it...

    The system can work with a small zone, but it needs to be controlled correctly. The bypass damper should be sized for the full air flow minus the smallest zone. Lets just say you have a 3 ton air...
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    You still have dampers in your residential...

    You still have dampers in your residential system, or at least you should. I do in my home and the ductwork was there before I was born. Sure all of the air that gets supplied will be returned but...
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    Registers have nothing to do with branch size....

    Registers have nothing to do with branch size. The supply grille is sized for noise [mostly] and pressure drop. You want a NC of under 20.
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    I've never seen pump out equipment on site or...

    I've never seen pump out equipment on site or ever seen anything like that in the code.

    The exhaust duct should be located wherever the refrigerant can collect. Since refrigerant is heavier than...
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    Thanks for the info. I'll call my Carrier rep...

    Thanks for the info. I'll call my Carrier rep since they handle First Co and see what the price is. I believe the contractor just priced out the Aaon unit and it was really high. I didn't actually...
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    The two hot water fan coil units with DX cooling...

    The two hot water fan coil units with DX cooling I've seen are rather expensive. I recently had a project in a hospital where I needed to spec exactly that, and I only found AAON and First Company...
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    Did you check the vent pipe? Bird nests and snow...

    Did you check the vent pipe? Bird nests and snow are known to be restrictive to airflow.:)
  33. Replies
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    I believe they were bought by McQuay, you might...

    I believe they were bought by McQuay, you might want to contact your local rep.
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    Pfff, everyone knows its 3.47.

    Pfff, everyone knows its 3.47.
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    Sounds like a typical reheat system. We design...

    Sounds like a typical reheat system. We design these all the time. Sounds like your problem is with not having an economizer. If designed corrected, the outdoor air damper should modulate allowing...
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    If you are borderline, go with the bigger...

    If you are borderline, go with the bigger furnace. With two stages, the gas consumption on both will be negligible. The price difference between the two air handlers should also be negligible. Better...
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    Cv isn't velocity constant. Just don't like the...

    Cv isn't velocity constant. Just don't like the sound of that since it is not related to velocity per se. It is the flow coefficient or valve coefficient and relates pressure drop and flow rate. The...
  38. Replies
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    Equal to the pressure drop across the coil so it...

    Equal to the pressure drop across the coil so it has valve authority.
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    1 cubic foot = 1,000 BTU/hr 1 therm = 100,000...

    1 cubic foot = 1,000 BTU/hr
    1 therm = 100,000 BTU/hr or 100 CFH
  40. You still bring in OA without an economizer, the...

    You still bring in OA without an economizer, the economizer just allows you to bring in more outdoor air if possible for free cooling.
  41. Replies
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    If this is a make up air unit for a kitchen, you...

    If this is a make up air unit for a kitchen, you can supply room temperature - 10deg for the make up. If this is a 100&#37; OA central air handler and you are heating the space, you need to increase the...
  42. Replies
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    You need to talk to a pipe fitter or hvac guy not...

    You need to talk to a pipe fitter or hvac guy not a plumber when it comes to hot water systems.

    That pump is pretty small. Assuming that its a 100,000 BTU/hr boiler, that pump will deliver 10gpm...
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    I'm more surprised that the contractor even gave...

    I'm more surprised that the contractor even gave the customer the option to have it piped from outdoors.
  44. Replies
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    You don't have to keep the vents 10' apart, just...

    You don't have to keep the vents 10' apart, just 10' from fresh air intakes or property lines. I always run my vents up through pate pipe curbs together for termination on condos or townhomes.
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    I don't know where you get 8 or 10 feet. You...

    I don't know where you get 8 or 10 feet. You can't exhaust within 10' of the property line or within 10' [or 12 or 15 depending on the local code] of a fresh air intake.

    The vent must terminate a...
  46. Replies
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    These are builder grade. You have R22...

    These are builder grade. You have R22 refrigerant, 13 SEER & an 80&#37; AFUE efficiency furnace. Those are the required minimums. If you are looking for high efficiency equipment it should be R410A & 16...
  47. It is energy code now to provide "free cooling"...

    It is energy code now to provide "free cooling" with economizers for any systems over 5 tons. If it is a VAV reheat system as suspected, look at the numbers, even at design temp of -10degF [here in...
  48. Replies
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    The IFGC lists the fittings that are acceptable...

    The IFGC lists the fittings that are acceptable in concealed piping. IIRC you can have standard couplings, tees, etc but no valves or unions. That is for commercial though, I am not sure what the...
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    They are ending that program since too many high...

    They are ending that program since too many high efficiency units are being installed now ;)

    $0.40 a therm, I am moving there!
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    Yes you can have too much outdoor air, but a 6"...

    Yes you can have too much outdoor air, but a 6" round depending on the length and how its installed, will not really bring that much outdoor air in just installed in the return air duct with no fan....
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