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  1. #1
    Join Date
    Aug 2011
    Location
    Northeast and Southwest
    Posts
    14

    Questions for American Standard specialists

    I知 a newbie to this site. I知 looking for help from any AS specialists in the audience.

    I知 in the quote process for a complete rework of the HVAC to a 50 year old, two story colonial in New England. I値l be converting form oil to gas. The system will be hydro-air. The Manual J is done. The specs call for a Viessmann WB2B-35 condensing boiler with an indirect domestic HW tank. The two zones use the new AS ForeFront AH model AAM7A0B30H21. Condensers are 4A7A5024E1 with BAYWABB07SC1AA hydronic coils. The AC performance is SEER/EER of 16/13 per AHRI certificate 4385744 which is plenty good for this climate.

    I知 the type of guy that likes to understand what I知 buying and I知 having trouble rounding up the AS data. I値l ask the bidders if I have to but I壇 rather save my questions to them for more pressing issues. I知 hoping you gentlemen can help:

    1. Is the Trane TAM7A0B30H21 AH functionally the same as the AS AAM7A0B30H21? I found the Trane publications for this unit but not AS pubs.

    2. Same question for the Trane 4TTR5024E1 versus AS 4A7A5024E1?

    3. My second floor zone is a long lineset situation at about 80 linear feet/120 equivalent feet. The AH is about 20 feet above the condenser. The Trane pubs for the 4TTR condenser send you to Publication 32-3312 for the details on what to do in this situation. I can稚 find this publication on the internet. Near as I can tell the standard 3/8 liquid and セ suction lineset will work with an extra loss of about 300 BTUH out of 2 tons. I can live with that. Am I missing anything?

    4. The Trane pubs on the 4TTR condenser also call out options that may apply to long lineset installations. Do I need the following options: Anti-Short Cycle Timer, Crankcase Heater Kit, Hard Start Kit?

    5. I壇 like to verify the detailed performance of the 4TTR condenser with the AH. However, I can稚 find the 鼎ooling Performance Extended Data. For some reason the Trane web page is empty at http://www.trane.com/Commercial/Prod...x?family=4TTR5. Can anyone help?

    6. My contractor has called out the BAYWABB07SC1AA hydronic coil as rated at 42,000 BTUH. I need 51,000 BTUH per the Manual J. However, I can稚 find anything on the web for this part number. I need the detailed performance charts that give BTUH as a function of air CFM and boiler water temperature and flow rate. Does anyone have this data?

    Thanks for reading my post.

  2. #2
    Join Date
    Dec 2010
    Location
    Palm Beach,Fl.
    Posts
    982
    The AH's are identical apart from the name badge. The condensers are identical at a component level and only differ in color and cabinet. Since the condenser is below the AH there should be no need for special considerations. I'll try to find the extended cooling performance for it.
    Quote Originally Posted by k-fridge View Post
    The laws of physics know no brand names.

  3. #3
    Join Date
    Dec 2010
    Location
    Palm Beach,Fl.
    Posts
    982
    That coil is rated at 70,000 BTU with the smallest coil rated at 50,000. I could not find extended heater data. I attached the PDF
    If the AHRI says its so, than its so. I confirmed it through Trane's dealer site but that data is not readily available to homeowners. Its a great system and I recommend it on all my estimates.
    Attached Images Attached Images
    Quote Originally Posted by k-fridge View Post
    The laws of physics know no brand names.

  4. #4
    Join Date
    Aug 2011
    Location
    Northeast and Southwest
    Posts
    14
    Thanks Dave. I’m looking forward to getting the 4TTR5 extended cooling data.

    I’m wondering if the extended heating data on the AS BAYWABB07SC1AA (or Trane BAYWVBB07SC1AA) hydronic coils doesn’t exist? This product is fairly new.

    It’s not possible to finish the system design without this data. The Manual J calls for 51,000 BTUH first floor and 23,000 BTUH second floor (first floor mostly driven by two fireplaces). In order to pick the AH CFM rate and the pump GPM requires this data (the Viessmann boiler temperature is a maximum of 165 degrees F so that’s known). When the AH is set to an outdoor multiplier of 2 (tons), the heating CFM can be set to either 800, 830, 870, or 900 CFM. The specified pumps are Grundfos 3-speed model 15-58 and you can also play with the size of the piping between the boiler and AH to help control the GPM. Lots of levers to pull but blind without the extended coil data.

  5. #5
    The data does exist. Ask your dealer to get it from the Trane/AS rep. Its publication # 18-GJ21D1-1 (Trane coil with same model # as AS). FYI, I just replaced my boiler with the same Viessmann W2B2 last winter and running it with a zone of Hydro air in New England as well. In the process of now replacing old air handler with new Trane VS Hyperion with HW coil.

    Viessmann is a sweet boiler! My experience is too oversize the HW coil a bit so you can run a lower water temp (within reason). You will probably want to play with the heating curves a bit on the boiler to maximize comfort/efficiency, so make sure you get all literature and know how to adjust the curves on the boiler.

    Dont hesitate on asking any questions of your dealer. If they can't or won't answer them, find a new dealer. I went through about 5 different dealers, before I found one who was up on all the technical stuff. In my experience, the dealer/installer is the key.

    Good luck.

  6. #6
    Join Date
    Aug 2011
    Location
    Northeast and Southwest
    Posts
    14
    Thanks.

    I've asked the dealer to get me the extended data on the hydronic coil and the condenser. The dealer selected the American Standard VS Forefront (same as Trane Hyperion) AH AAM7A0B30H21 to be able to install the 70,000 BTU coil for both the first and second floor. Since the BTUH load for the first floor is 51,000 and 23,000 for the second floor (after 12% adjustment for glycol to -10 degrees), he could have specified the AAM7A0B24H21 AH with a 50,000 BTUH hydronic coil for the second floor but didn't because he said that the B30 will run quieter. I agree with him as the B30 blower wheel is larger than the B24 and will run at a slower speed.

    Once I get the hydronic coil data (this week?), I'm hopeful that I can "dial back" the coil BTUH using the available four AH heating fan speeds and three GPM Grundfos pump speeds. Changing the boiler heating curve is an option I hadn't thought of. Basically I want full boiler temperature at 0 degrees F outside temperature.

    You're correct about finding dealers. I've had to get competing furnace quotes to get competitive costs. It's hard to find hydro-air installers and the bids are more complex to put together. This dealer has been up to speed on all of the technical issues except for some minor items and I'm dealing with the President of the company (rather than a salesman) which is a good thing.

    It's interesting what the quotes have shown. The hydro-air system uses an indirect hot water tank. The furnace options use an HDP Phoenix PH100-55 hot water heater. The furnace system costs (including HW) are less than the hydro-air system but not by much. I'm partial to the hydro-air due to the flexibility; the design will be plumbed for easy expansion to two future zones for the basement and garage.

    Here's a question on the Viessmann W2B2. What happens if the indirect hot water tank pump fails? If the boiler is set to hot water priority, will the entire system "lock up"?

  7. #7
    My indirect is set up as auxiliary on the boiler and I do not utilize the DHW priority for that reason. If there is an auxiliary call on the boiler, I have it set up so the boiler will ramp up to max temp 165 and ignore the outdoor reset and the curve. I have a 75 gallon indirect and it works great.

    You also may not need a water temp that high on a 0 degree day, especially on your second floor. With such an oversized coil, I think the boiler will short cycle with such a high temp. The boiler seems to be most efficient on lower return water temps and long heat calls. I have been able to heat my house with max of 140 degree water on a 0 degree outdoor temp. I have also seen a savings of 30% on my gas bill

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