UPS26-150F speed shaft broke
I have a UPS26-150F and the speed shaft broke. The pump is from 2018 so shame to chuck it. My plumber already swapped it out but it would be nice to refurbish and have this as a spare.
Is it possible to order the board assembly? Grundfos tech support redirected to local wholesaler who then said they have to call grundfos.
I am waiting for a call back but hoping someone just knows the answer.
Comments
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the shaft is ceramic so they can break if jammed or hit with a hammer🤔
I doubt you could buy just the armature part 6, assembly and if so it would cost as much as the whole assembly, probably
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
2 -
Are you referring to the speed switch?
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.
1 -
Yes, it broke into pieces - seemed like heat stress. I am thinking I'll need to replace the whole electronic control module.
0 -
you could always salvage a part from a failed pump that has a working switch.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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do you need to be able to change the speed? If not just wire the speed you want and skip the switch
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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Honestly I am not sure.
The hydronic system was originally installed in the late 60s. Parts have been changed over the years and I don't think a lot of intelligent design went into the system. I've only recently come on the scene with the building manager getting closer to retirement.
There are two boilers controlled by a tekmar 274. It seems like only one of the boilers is firing up - I still have to dive into the tekmar controller and see if it is setup properly. The building manager seems to think that each boiler used to alternate but I watched it run for half an hour and only one of the boilers was cycling. I am also not sure how often a boiler should run for before turning off. System could probably do with an indirect tank instead of cycling all the time. Each boiler has a IFS and a circulator. The output water of each boiler 1 1/4" feed into a 2" before hitting an air scoop with an automatic air eliminator and a large expansion tank. The flow then hits the UPS26-150F. This is a 3 story building with maybe 20 units and these boilers are only doing heat via baseboard radiators ( short fin based ones ). The flow then hits a safe-flex before splitting off to the different sections of the building in 1 1/4" pipe which eventually twigs out into 3/4 lines feeding the individual baseboard heaters.
The delta T on the tekmar was something stupid like 2F and the UPS26 was set to high in addition to one boiler circulator set to mid and one set to high. I've put the UPS26 down to mid and the circulators down to low. The delta T is still only 8F. I'll need to play with it a bit and get more familiar. The failed UPS26 is from 2018 so that doesn't seem like a great lifespan but all the pumps are on the supply side and too hot to hold your hand on for very long. Pressure is sitting at 25psi and the relief valves are 40psi valves. I think the boiler target is set to 160F and the system has an outdoor reset.
My thought on the failed UPS26 was just to get a new controller part complete with the speed shaft and then throw the UP26 into a test rig and see if it is fine. The pipes were banging and the plumber who replaced it had never swapped parts in a circulator before so it didn't seem like a great fit to have him play around with trying to fix the UPS26.
A bit of a learning curve for me.
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The delta you're seeing probably isn't under full load, so it would rise exponentially when all zones are open on a design day. Many of these systems are set up as a lead/lag so boiler 2 never runs unless boiler 1 can't keep up which also sounds much like what you're seeing. The circulator did not "fail", the speed shaft broke most likely from some trauma. If it's moving the fluid adequately, you can just leave it alone and disregard the broken shaft for another 10+ years until it's due for replacement.
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I just replaced a 26-99 on an ODWB that was 20 years old for the same reason: the switch broke because the HO kept fiddling with it. They’re designed to be set at the proper speed and be left alone.
IDK of anyone who offers parts for these pumps other than the motor cartridge or check valve.
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.1 -
That's true. Certainly far from a design day. I guess what I'd expect is that during non-design days - most of the heating season - the outdoor reset would help tekmar to tell the boiler not to bother firing? 160F seems hot to have as the boiler target and if the return is coming back at 150F that seems wasteful to have the boiler fire to heat that water up the 10F?
I am also confused as to why someone would install the 26-150, doesn't this imply 150 feet of head and in a 3 story building the system probably only need 30-40 feet? The 150 does have 1/2HP vs the 26-99 which would only have 1/6HP. Guess I'll have to wait for a day that is closer to design temperature
In a lead / lag setup do you rotate the boilers so each year the primary is a different boiler?
The plumber already swapped in a new UPS26-150 so I suppose if I am still looking at it in 20 years I can use the circuit housing from the new one on the body of the old one - haha. The pipes were knocking but I don't think he really had the diagnostic skill to determine that the pump was bad ( it seems to spin freely when I manually rotate it ). The speed shalf was discolored and crumbled which was why I was guess heat damage but I suppose it could have been trama and this is just the default look / feel of the shaft.
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The height of the building has nothing to do with dynamic head in a closed loop.
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.0 -
in a closed loop system “head” refers to the energy the circulator adds to overcome all the flow resistance in the circuit
So the pipe, valves, heat emitters, boiler, etc
Buildings with many air handlers with small coil piping tend to use a high head circulator.
If the building had large piping, cast iron radiators, typically a lower head circulator would be used.
The pump or its replacement should be sized to the buildings load characteristics
Multi speed circulators give you some adjustability
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
What they ^^^ said, with the additions of:
A cast iron boiler needs to run with return temps of 140*+ to avoid flue condensation and therefore corrosion, so ODR does not act like it might with a low temp system and condensing boiler.
Lead/ lag is almost always set up so that boiler 1 is always boiler 1, meaning that one wears out first. Some are set up to switch at certain intervals or sometimes even with every firing, but that's a little more involved for the control guy as well as adds upfront cost so it very seldom happens that way.
I've got a number of systems that only rise 4-6ft to the ceiling but require 20+ GPM through a highly restrictive coil and 3 way valve (usually makeup air for indoor pool rooms) that require a 26-150. Static height has nothing to do with sizing of a circ in a pressurized system- the pressure itself does the lifting.
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