Does this look like I might need to demand a ScheduleJ then push Upgrade? - GreenBuildingTalk - GreenBuildingTalk - Green Building Forums on Insulating Concrete Forms (ICF), Structural Insulated Panels (SIP), Radiant Heating, Geothermal Heat Pumps, Solar Power, Green Construction Projects - Green Building Technologies

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Does this look like I might need to demand a ScheduleJ then push Upgrade?

Last Post 26 Aug 2019 10:45 PM by tommytx. 4 Replies.

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tommytx

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Posts:4

20 Aug 2019 06:16 PM
I have been having problems with my 2nd story split GEO Hvac unit keeping up with the temp once outside temp reaches 77... They have tried tons of stuff.. but seems like no one knows how to do a Schedule J load calc, nor a schedule D for my new ducts.. So just looking at rough specs.. I am wondering if i should put my foot down and demand a Schedule J even if i have to pay for it.. and based on the results push for an upgrade to a 3 ton... I have a 3ton bosch downstairs but it does have more space.. Thanks for any suggestions.. And pls don't start with sqft does not determine equipment size.. I know that... but can give a ball park guess... After doing a quick review of this I am wondering if my entire problem is a simple matter of undersizing.. I know 400 sq ft per ton is a wild assed guess but gives an idea.. and 555 + 427 = 982 total.. suggest that i may be undersized... then add the huge walls of the master exposed to the 130 degree attic and a total of 8 large windows.. maybe I should hire a professional to do a detailed Schedule J and then use it to force the contractor to move me to a 3 ton at his full expense.. I already go him to change the 3 ton Trane on floor 1 to a 3 ton Bosch... getting real expensive for this contractor... Since the entire area is covered by a 130 degree attic and one bedroom has huge wall with 130 degree attic on the other side.. it just may be undersize and only a thorough Schedule J would tell.... and while I am at it get a Schedule D done so they can straighten out my trashed brand new Duct work. Any thoughts? Ideas? Do we have any commercial hvac guys in the Hampton Roads area interested in taking on the schedule J and schedule D... contact me.. Thanks. Master Bedroom -------------- Bedroom 350 sq ft 1/2 Hall 20 sq ft Closet 20 sq ft Bath 140 sq ft Nook 25 sq ft ------------------- 555 sq ft has 5 windows and almost all are outside wall 130 degree attic above entire room.. registers and flex in attic along with 2 ton airhandler.. Two of the walls in this room have attic on those walls 130 degrees. The rest is mostly to outside air. Bedroom #2 ------------------- Bedroom 266 sq ft Nook 16 sq ft Nook 25 sq ft Hall 30 sq ft Bath 50 sq ft Closet 20 sq ft half hall 20 sq ft -------------------- 427 sq ft has 3 windows and almost all are outside wall 130 degree attic above entire room.. registers and flex in attic along with 2 ton airhandler.. Rule of thumb 400 sq ft per ton.. not valid but very rough guess.. Based on that I am undersized and would explain all the problems.

sailawayrb User is Offline

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21 Aug 2019 03:50 PM
It would be highly unusual for a HVAC company to under size a cooling/heating system. The average HVAC company will typically grossly over size cooling/heating systems which may result in significantly reduced operational efficiency. They would rather not get a call back from you because you are too hot or too cold knowing most folks are clueless about efficiency and will just pay their monthly bills. So yes, the first step is always to accomplish an ACCA Manual J (or ASHRAE) building heat gain/loss analysis BEFORE sizing and installing the cooling/heating system. Perhaps hire an engineer to accomplish it to get an accurate and realistic determination which should cost you no more than $500. I assume this is a new installation that has never performed well. If so, it could just be a bad installation that needs some competent eyes to go over it and correct it. We have free DIY heat gain/loss analysis on our website should you be so inclined.

Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!

tommytx

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Posts:4

25 Aug 2019 10:39 PM
Not actually a new install... its a new install over the 30 year old Florida Heat Pump..Problem is its a geo and the company that installed it have never done a geo before.. however they are a large well known company specializing in Trane with many years experience non geo. And what I am finding is that its very rare for a company to do any Manual J, S, or D for that matter.. most do not seem to know much about it.. and just fly by the seat of their pants duplicating what exists and hoping the guy before they did it right... its sad to expect that 30 years ago they were smarter than we are now.. Correct it has never performed right since rework.. did quite well for 30 years but the old Florida heat pumps are old.. and one is leaking freon. so decided to upgrade both of them which was a big mistake.

sailawayrb User is Offline

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26 Aug 2019 03:11 PM
Is the new heat pump similar in Btu/h rating to the one that it replaced and which worked well previously? If so, I would speculate that you just have a bad installation and would recommend that you focus on remedying that. You can’t properly design the system and achieve maximum operational efficiency without a proper Manual J or equivalent. However, for an existing building and system, you can accomplish the equivalent via an energy usage analysis: Borst Existing Building Energy Usage Analysis Software It is true that finding a good designer or installer in some areas can be challenging. Finding one that can do both can be extremely challenging. And a ducted ground source heat pump system is about as complicated as it gets. Also please keep in mind that newer systems are significantly more efficient than what you had. So a smaller Btu/h rating is entirely appropriate and especially if the original system was over sized which unfortunately is commonly done.

Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!

tommytx

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Posts:4

26 Aug 2019 10:45 PM
Yep many signs that it was not a bad install that I got it was a horrible install. Currently in BBB waiting for mandatory Arbitration for 19 September 2019. No equipment is needed to see how horrible just a simple visual will do the job.. For example: All 21 of my flex runs off the trunks is 6" flex... now how incompetent is that .. My poor little 25 squarefoot bath gets one run of 6" with no throttle.. to set it lower.. while my 400 sqft bedroom gets two runs of 6" flex.. how nice there is 16 times more sqft and it gets twice as much air as the bath... I hope to get the arbitrator to allow me funds to get the work done by a tiny bit more technical company.. but seems to be hard to find one that even knows as much as i do... since my contractor has already hired 2 other so called geo experts and they have no idea what they are doing.. at least my contractor was smart enough to realize he did not know what he was doing and asked for assistance. However he appears to be so deep in the dark that he is not even able to hire a third party that is much smarter than he is... No one has done any Manual j, S, or D. The D would have been wonderful to show them that you cannot use the same size ducting for every job.. the one size fits all just does not work in ducting... that is unless all rooms are they same size... As far as I know they tried to match the tonnage ton for ton.. but they sure as heck screwed up the one for one on duct sizes.. I have several sizes of ducting originally now they are all 6" flex. They have no clue.. but does explain why my bath has a temp of 72 while my bedroom has a temp of 77 and when the outside temp is 79- 95 my 2nd floor is 80-94.. not good.... So far i have written a 500 page manual of screwups titled.. "How not to install a GEO!" to be published soon.. its unbelievable and would be hillarous if it was not so painful..