Maryland Variable Speed Pump Failure - after 4 yrs

Discussion in 'Maintenance and Troubleshooting' started by Jamie V., Mar 27, 2019.

  1. Jamie V.

    Jamie V. New Member

    I have a Water Furnace Series 7 that was installed in 2015 and worked flawlessly until last week when I had an error code #16 which indicated a variable speed pump failure. This was confirmed by the technician and they have ordered a new pump for replacement. He also found out that my AUX heat unit was causing a loud buzzing due to stuck relay (we never have needed aux heat so this could have been a problem for years) so that is being addressed as well.

    I was surprised that the pump would fail only after 4 yrs... is this the typical lifespan or did I just have some bad luck? I'm not too concerned this round since it is a warranty replacement but once I get past 10 yrs this part could become a "consumable" which makes me wonder... how easy is this to replace? Is this just a swap out or do is the procedure a more labor intensive (e.g., depressurize the loop)?

    Thanks!
     
  2. nc73

    nc73 Member Forum Leader

    I have found that anything that is variable speed will fail prematurely compared to single speed. No such thing as bad luck.
     
  3. RunTime

    RunTime New Member

    Can you post a picture of the pump as it is installed? Make and model number too? Pumps can be a diy replacement, it's mostly a matter of managing the water spillage and refill.
     
  4. Jamie V.

    Jamie V. New Member

    Here is a picture of my pump setup... It is a Grundfos Magna 32-140.
     

    Attached Files:

  5. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Yes, the pump can fail. Not to worry too much, other fail too.

    The 7 series needs a variable speed, so it can maximize the energy savings. Have them put in a new one and move on. Enjoy your 7 series.
     
  6. JD B

    JD B New Member

    My Geo HP circ. pump Grundflos UP26-99F is at least 18 years old and have reason to believe it may be orig. to the 31 year old system on a pressurized system. It's a single speed and runs a 2 ton unit. I was told by a non-pressurized flo center rep that while a variable/multi speed pump saves energy costs - the pump life is shortened. Given pump R/R cost, I wonder if the exchange of kw savings reduced by premature pump failure cost. Would be interested if anyone has crunched the numbers.
     
  7. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    proportionally your 26-99 will use a large amount of energy. You only need 5-6 gym.

    I have one on my 6 ton geo units....

    We have similar pump failures on a variable speed versus a constant speed.

    the 26-99 uses 235 watts when running, the variable speed depends on its pumping power it needs to deliver. It also runs more (the variable ) when combined with a variable speed heat pump.

    But we install the variable speed circulator in almost every application, even with dual speed heat pumps. But those (dual speed heat pumps) are getting rare too.

    Variable speed is the future....
     
  8. JD B

    JD B New Member

    I live in a small town of less than 7 thousand that has no Geo HP HVAC trained techs - after 31 years, original installer retired. But the age of the HP and manner of loop, headers - not manifolds, confuses the younger geo-techs from the nearest HVAC company. A bit worrisome in making decisions regarding changes to original configuration. Would deeply appreciate your input - do you see any issues or impact on older HP or loop on changing out the 26-99 single speed with a variable speed pump? Does the pump itself determine pumping speed demands or would that come from the HP unit? If from the HP, how would I determine the HP ability to monitor/regulate AND would the VS pump need to be wired differently to the HP?

    Home is passive solar and loss of HP function in 100+ summer heat or loss of heat in freezing winter temps a concern. For anyone wondering about the effectiveness of passive solar - if the sun shines, I've had it heat the home to mid 80s in zero degree temps. The problem is you can't turn it off in the 100 degree summer days - just reduce its intrusion into the home. More winter than summer, so its all good when the HP cools at an efficient cost. Egro - pump life enters into the decision loop.
     
  9. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    What loop, heat pump, configuration do you have? Single stage? Forced air? How many 26-99?
     
  10. JD B

    JD B New Member

    Closed loop - 4 trenches 6' deep 100' long 15' apart of 1" polybutylene pipe that connect to 100' 1 1/2" header line. No manifolds. Loop connects to the original Command Aire Loop Pump Kit (LPK) pressurized flo center that has an air expansion chamber and isolating valves each side of a single 115v Grundflos UP26-99F one speed pump. The line was installed with 15 to 20% propylene glycol. The HP is a 2 ton Command Aire installed 1988 with a manual switch 2 phase heat/1 cool thermostat. This a ducted forced air configuration.

    The unit performs to 11.1 EER and 4.1 COP. The unit serves 1470 sq ft of conditioned space in a SIP built home.
     

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