WF Series 7 Desuperheater E15 HW Limit Faults

Discussion in 'Maintenance and Troubleshooting' started by josephparris, May 7, 2013.

  1. josephparris

    josephparris Member

    Ok, I have purchased another water heater. I am currently using an 80 gallon water heater. It is currently plumbed with the desup so I am going to make it the buffer tank and the new one my supply tank. Would someone let me know the ideal and correct setup. I understand the plumbing, but is anything else needed such as a back flow valve and if so where should it be placed? Anything else? I want to make sure this gets done correctly so I can get the most out of the desup. Currently I am getting nothing using a single tank.

    All ideas would be appreciated.

  2. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Try this

    Attached Files:

  3. josephparris

    josephparris Member

    Thanks, I will make sure I follow it exactly.
  4. Bergy

    Bergy Member Industry Professional Forum Leader

    It's important to install the top ball valve ABOVE the water heater's incoming water ball valve. Once all the piping is done just shut off the main ball valve, open a hot water faucet and the desuperheater loop will be flushed.

  5. josephparris

    josephparris Member

    Thanks, consider is done!
  6. josephparris

    josephparris Member

    Ok, yesterday morning I installed my buffer tank, reset my E15 hot water faults (limits). It has been installed exactly like Joe's sketch above. With very little runtime since yesterday I now have 3 faults.

    Ok WaterFurnance, now what????? I am starting to be disgruntled!
  7. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Are they still hot water faults?
    You needed the buffer tank regardless of whether that was the cause of the codes.
    I do not know exactly what the "fault" means. Is it an indicator of a satisfied temperature or does it suggest over temp.
    Your exasperation should be directed at the installer, not WF.
  8. josephparris

    josephparris Member

    Yes they are hot water faults. The limit is set to 130 degrees. The buffer tank has not been above 76 degrees since installation. I have talked to my installer several times and he was in contact with WF about my issue and they said I needed a buffer tank, even though their installation instructions show the desup plumbed with and without a buffer tank.

    The installer has also been out and changed the sensor about a week ago, but that was not the issue.
  9. geoxne

    geoxne Active Member Forum Leader

    Please consider the following before you get disgruntled.

    E15 is not considered a fault. It is an alert for information only. The control board contains logic that disables the DS pump at temperature limit AND when very little superheat is available. This prevents the refrigerant circuit from stealing heat from the hot water tank. This may occur most commonly at the beginning of the cooling season when loop temps are still <50F.

    The Series 7 IOM Pg 29 describes E15 as follows-
    E15 - HW over limit or logic lockout. HW pump deactivated.

    The Series 7 Specs show no HW Capacity available with Unit EWT's below 60F.

    I am not sure what logic is used to disabled HW but it may be EWT or comparison of refrigerant temp to entering HW temp.

    Be patient. As the season progresses loop temps will rise and so will HW performance. I hope this helps.
  10. josephparris

    josephparris Member

    Ok, I will be patient. My current EWT and LWT are in the low to mid 60's. my buffer tank has not gotten any higher than 76degrees. The link below from a previous post shows their buffer tank at 89 degrees. I find it hard to believe my system can raise my buffer tank that high with the current E15 "alerts".

    I will be patient, give it time, and let's see what happens.

    What can I expect for buffer tank temperatures?

    Temperature and Energy logging by: Web Energy Logger
  11. josephparris

    josephparris Member

    Actually if I look at the welserver link above their desup EWT and LWT water temperatures are right inline with mine at the moment.
    Mine are currently desup EWT (70.06) and desup LWT (74.69).

    patience is a virtue!
    Last edited: May 27, 2013
  12. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Dsh temps depend on loop temps and wether the unit is in cooling or heating mode. It is possible that DSH pump is disabled in coolimg mode with loop temps below 60F, since it is possible that otherwise heat from the buffer tank is rejected back in the loop.
  13. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Frustration with your installer would not be out of line if he lacks the education on the product he sold you to determine whether it's working correctly. All of us continue to learn, but few of us throw up our hands and ask the manufacturer for help troubleshooting. In fact their odds are worse than mine in diagnosing trouble because they aren't on site.
  14. josephparris

    josephparris Member

    Point well taken!
  15. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Joe Harris:

    If I see Joe Hardin throwing up his hands, I drive up to Michigan to learn why. At the price of fuel we mostly send our money to ISP and Wireless.

    Mr. Harris is there anything you can do to measure flow?

  16. josephparris

    josephparris Member

    Parris? If you are asking me, yes I do have a flow meter installed in the desup out line to the buffer tank. Flow is about 1.8 to 2.0 gpm's when the pump is running. New Picture (1).jpg
    Last edited: May 29, 2013
  17. josephparris

    josephparris Member

    Ok, this is just a little feedback on my desup after having the buffer tank for the past couple of months. Things seem to have settled down and now during long run times the desup is raising the buffer tank water temperature to ~108 degrees. I will admit the buffer tank has made a tremendous difference in the amount of hot water the desup has made.

    Thank you to all who replied and helped with this issue!
  18. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    May I quote you on that? We have sales literature with pre-emptive rebutts to the other guys who don't employ best practices (keeping their cost down to underbid us).
    The DSH buffer is one of the bullet points.
    I trust you have shared this with your installer so that he will be on board with the "good-guys" now. Too bad the manufacturers aren't paying attention.
    Doc, you speak German, maybe you can get the Bosch guys to be the first to poo-poo the single tank install LOL.
    ChrisJ likes this.
  19. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    They are interested in selling the DSH option on as large a percentage of systems as possible, regardless of suitability or payback in the cases of clients who can't or refuse to install the 2nd tank.

    I haven't dealt with a 7 series, but can imagine a scenario where a long hot afternoon of cooling yields a preheat tank at 100+ degrees, but then after dark much lower loads could cause compressor hot gas discharge temp to fall below buffer tank temperature. Agile controls are needed to keep that from happening.
    Last edited: Aug 3, 2013
  20. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Mr Parris:

    I could have been PWI. Sorry.


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