Pennsylvania E5 - Frze Detect FP1 errors with Waterfurnace Series 7 and Ground Loop

Discussion in 'Maintenance and Troubleshooting' started by stevelion, Jan 19, 2016.

  1. stevelion

    stevelion New Member

    I’m looking for expert advice on what may be the cause of my problem and suggestions on what to do to resolve.

    I have a 4 ton Waterfurnace Series 7, vertical, closed loop system (more details on the ground loop to follow) installed in a 2625 SQFT home. In the coldest days of winter, I’m experiencing repeated E5 - Frze Detect FP1 errors which typically result in a system lockout and switchover to emergency heat. The system was installed in 2014 in Southeastern, Pennsylvania. The system performs very well in warm weather and cold weather except when we have repeated days where the mean/low temperatures drop into the teens and single digits (Fahrenheit). We experienced 124 of these E5 errors during the 2014/15 winter.

    When this problem first started, the installer worked with the WF engineers and decided to look at changing the glycol/water (I believe it is glycol based) ratio in the loop suggesting that the installer had used too much glycol thereby reducing the heat transfer capacity of the system. Additionally, the single, variable speed ground loop pump was set to a fixed, high flow rate to increase the turbidity in the loop.

    On making these changes, things got markedly worse in terms of numbers of E5 errors in the weeks after. The theory then was that air was inadvertently injected into the system during the rebalancing of the glycol/water ratio. On next attempt at repair, the loop was primed again with a larger pump and it was believed that, in fact, air was removed from the system. However, by the time this work was completed, the heating season was nearing its end and temperatures rose consistently into the 20’s and higher and so it was unclear whether this action had any real impact on performance. Now we are experiencing the first significant, prolonged cold weather of the 2015/16 season and the problem has reoccurred.

    The ground loop is made of 4 loops of 1" piping consisting of 11 total bores of varying depth as follows. The nomenclature below is: Loop # / # of bore holes / individual bore length summed for total length of loop in ft.

    Loop 1 / 4 / 60+50+50+40 = 200’ total

    Loop 2 / 3 / 70+50+70=190’ total

    Loop 3 / 2 / 95+90=185’ total

    Loop 4 / 2 / 90+95=185’ total

    The reason given for the odd setup was related to the challenges met when boring in our heavy clay. Water was entering the bore holes as early as 20’. It is my belief based on talking to the drilling sub-contractor, that little casing was used, but much more grout was used than anticipated.

    To reiterate my goal, I’m looking for expert advice on what is causing my issue. It is my belief that the ground loop does not have enough capacity which could be either due to an under-sizing issue, a configuration issue with the unusual number of bore holes looped together, or some combination of both. My plan is to continue to work with the installer to get resolution. To date, they have been very responsive and have been in the HVAC business for long time in this area. I’d also like to have opinions on what might be an acceptable solution. e.g. increase length of existing loops, add a fifth loop, start over and re-drill, etc.

    Thanks in advance to anyone willing to help.
    Last edited: Jan 19, 2016
  2. LMNtary

    LMNtary New Member

    Hello Stevelion,
    Your post caught my attention because I popped that same fault last night on a new 5 Series machine. My installer tells me that the DIP switches on the machine had not been properly reset during install, and so they were still configured from the factory for an open loop system and associated temps. Sounds like your circumstance is longstanding, much more complex, and it is hard to imagine that simple step could be overlooked by a provider...
    That said, my fault cleared and has not returned.
    I am purely parroting back what I was told, so buyer of free advice -- beware ; )
    Good luck!
  3. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    To assess the ground loop, you should be monitoring your entering water temperature. Is it actually getting to temperatures that make the fault legitimate?
  4. stevelion

    stevelion New Member

    While I do not recall the exact set-point, we have confirmed that the faults are occurring as they should per Waterfurnace. The faults occur around 20 deg f and I believe that is on on the entering temp vs. the discharge. At this point, I believe the only question remaining is what can be done to keep the loop temps from getting this low. e.g. changing glycol/water ratio (to be correct per specifications), increasing loop pump speed to increase turbidity, etc. Of course, "etc." may be limited which is what I'm trying to find out. I'm no expert, but the only conclusion I can draw at this point is that the ground loop is not performing adequately either because it is not operating at full capacity (e.g. one loop is locked out perhaps with air) or the loop is undersized. Of course, I'm hear to get expert opinion and so am happy for any other ideas.
  5. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    What size is the loop piping?
  6. stevelion

    stevelion New Member

    1" piping. OP updated with this information. Some other information that might be useful... Currently, it is 20 deg f where I live. The EWT is 36.2 deg f and the LWP is 29.5. The system is extracting 27621 Btuh. Entering air temp is 70 and leaving is 93.2. WaterFlow rate is 8.4 GPM.
    Last edited: Jan 19, 2016
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    According to the Dutch, one can only move 109,000 BTUH @ 10.9 GPM.

    That is all the heat you get. I would have gone to 1 1/4" pipe. That would allow 163,000 BTUH.
  8. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    E5 obviously means that the freeze protection got triggered.
    First, is the dip switch set to 15F and not 30F freeze protection, since you have antifreeze in the loop.
    Second, too much glycol does not trigger an E5 error.
    Third, to set the variable speed circulation loop pump to constant speed for better turbidity is silly. It would be to change very efficient pumping to very inefficient pumping.
    Fourth, do your faults occur at 20F outside temp or 20F entering water temp? If your loop is at 20F it is not performing.

    Then you say your EWT is 36.2F. Is this after restarting the unit, or after it run a while? Your water flow of 8.4 gpm is at what compressor stage?
    Any idea what your pump setting are right now? Do you have access to an aid tool from the installer. Your readout seems to indicate that.
  9. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    All good questions. I'd want to independently confirm, perhaps with a temperature clamp, the tube temperature at the FP1 sensor.

    System should work fine with EWT anywhere in the 30s assuming good loop water flow.

    If system has PT ports consider investing in a Cooper Atkins reduced tip probe thermometer (<$30)

    Mating a sport ball inflator tip with a halfway decent 0-60 psig pressure gauge also costs less than $30 and you are on your way to performing your very own flow rate and Heat of Extraction calculations independent of AID tool readouts.

    If the system lacks PT ports you can at least tape the probe of a digital thermometer to the bronze water fitting and get passably good water temperature readings in and out.
  10. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    Check the sensor value?

    Why do that?
  11. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Because the sensor can be off, indicating a lesser temperature than actual. Happens sometimes on the WF.
  12. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    Sounds to me like MC was being facetious but DJ didn't pick up on that!?!?
  13. stevelion

    stevelion New Member

    I have an update on this issue. The FP1 sensor is and was set at 15 deg f. I'm still fairly sure that the LWT I saw on Symphony were about 20 deg f when the FP1 error last occurred. Perhaps the variance is normal. It turns out there was an incorrect setting limiting flow rate at the high end to 60%. It is now set at 100% and I can see the flow rate has increased. Where it was around 8.5gpm at the highest speed (12), that flow rate is not 13.5gpm.

    Regarding too much glycol not triggering the E5...completely agree and did not mean to imply that it could. The issue is that too high a glycol to water ratio reduces the heat transfer properties of the brine such that the brine does not effectively exchange heat with the earth as it would if it had a higher water content.

    As I learn more about this issues, one thing I am really starting to question is why this issue doesn't just result in excessive use of the auxiliary heat strips. If the unit is seeing the FP1 sensor temps get down closer to 15 deg f, why doesn't it just turn on the aux heat to reduce the load on the loop. In fact, isn't this part if the proper design of a properly sized system? I do see the heat strips come on as emergency heat after the system locks out, and I can see the auxiliary heat come on if I raise the thermostat by (e.g.) 3 degrees, but I do not ever recall seeing auxiliary heat when the FP1 errors were occurring. Basically, the Geo satisfies the thermostat (set at 70) continuously up to the point it locks out. In other words, unlike the "artificial" difference I created by raising the thermostat 3 degrees, the FP1 errors occur without a gap in the systems ability to satisfy the thermostat up to the point it locks out.
  14. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    1. treating serious issues with deliberately inappropriate humor

      I had to look up facetious. Sorry, not my native language.
      And indeed, I often have trouble to comprehend Mark's expressions. Maybe I am getting too facetious now....:cool:
  15. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    scherzhaft for Dr. Ponikau.
  16. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    What is your min and max flow rate (%) set now, and what are the GPMs at min and max flow rate?

    While higher PG concentrations have an effect on heat transfer, +/- 5-10% is not really that significant.

    Supplement heat: The units and the system should be designed to extract heat and not drop to 15F LWT. When loops drop below freezing and you start to make ice in the ground, that means that water in the ground goes through a phase change from liquid to solid and releases a large amount of energy ( That's why a loop field is hard to screw up, since it rarely drops below 25F EWT, although some people manage to do it!
    Now, you have an unusual loop design, that is why I am asking when you see what kind of temperatures, and what your flow rates are. Some people might blame it on the glycol concentrations, when in fact it is the loop field not performing. Too early to say here.
    All you have to give your heatpump is a certain amount of fluid at a certain temperature, it needs not much else to remain happy. It is really that simple. Your flow was off, which screwed up your temps.
    You supplement heat is meant to provide some extra heat for the peak capacity, for the 5-10 days when you have really cold nights. A larger heatpump could do that too. The total amount of heat the supplement heat element should provide is usually only 2% of the total energy over the season. It is not meant to keep your loop warm. Your loop shall never drop from 30F to 15F within a cold span. You should see it drop by a degree or two, but that is about it.
  17. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I would translate "Scherzhaft" more with humorous (or "humorvoll"). Facetious seems to more ironic or sardonic.:rolleyes:

    What do I know. I had to look it up in the dictionary a couple hours ago.....;)
  18. ChrisJ

    ChrisJ Active Member Forum Leader

    Looking at the different depths of the wells, how can one be sure there is flow through all loops?

    Seems like it would take a complex header system. Is there a possibility that brine is being lazy and seeking the shortest path in some of the loop sets?

    geoxne likes this.
  19. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    Ich spreche nicht so gut Deutsch
  20. geoxne

    geoxne Active Member Forum Leader

    My bet is ChrisJ is on the right track. Loop 1 with 4 verticle bores piped in series is air locking. Maybe even Loop 2 with 3 verticle bores. Air locked loops are cutting loop field capacity in half. This is not your typical flush and purge. Time for a "super purge".

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