Circulating pumps not working


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Old 04-06-21, 12:28 AM
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Circulating pumps not working

Little background info: We have a 5 ton GeoThermal Heat Pump and recently one of the pumps rusted through and broke. I spoke with the repair people and they won't be able to make it out here for 3 weeks, so I decided to try and find a new pump and install it myself. I called around and found one from a place that specializes in plumbing and they said this one should work. The new pump has slightly different connections, but I'm pretty sure I wired them up the same way they were before. Problem is they aren't working. The unit turns on and the compressor turns on, which is usually when the pumps start running, but the pumps aren't doing anything. The compressor then turns off after 10 or so seconds. What am I missing? Are these wired correctly? Will these pumps not work together?

Old Pumps: both Grundgos UP26-116F 230V
New Pump: Grundfos UP26-99f 230V

This may or may not be wired for 115V. For whatever reason, the original guys put 2 230Vs on there. My multimeter read somewhere around 115V on both pumps, but I'm pretty sure these are wired in parallel, so maybe that's the way they're supposed to be? I'm really not an expert on any of this. Just a homeowner trying to fix the damn AC quicker than a month.

Anyway, does anything wrong jump out to anyone? I'm at a loss here. I'm almost positive I wired them the same way they were, but the new pump threw me for a loop with the different connections and, since it didn't have a hole in the bottom, I had to move the new pump to the bottom.


How top pump was originally wired (broken one)

How both pumps were wired in-line (bottom one still works)

New pump on bottom, old bottom pump moved to the top.

Oh and pardon all the mud. I know it's a mess. It's an open system and we aren't sure how the water is getting that dirty, but it's a problem for another time.

First time posting, so I hope I did this right. Thanks!

EDIT: Sorry I just noticed there's another forum specifically for heat pumps and I can't find how to delete this one. Still applicable here, maybe it's more of a basic electrician problem than a plumbing one anyway? Idk.
 
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Old 04-06-21, 03:03 AM
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Welcome to the forums.

I deleted the other thread and left this one here. It's a basic electrical problem.

Pump motors are run in parallel. If you have 120v supply..... you need 120v pumps.
240v pumps won't run on 120v.
 
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Old 04-06-21, 09:44 AM
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It looks like both your old and new pumps are 240v (230v in their spec sheet). So they should be wired for 240v across the white/black incoming wires. In parallel as Pete mentioned.

But the bottom pump shows H/N terminals, which isn't correct for a 240v pump, it should be labeled as H1/H2. Which is odd to me at least).

Do you get 240v when you measure across the White/Black incoming wires?
 
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Old 04-06-21, 10:40 AM
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PJmax
Any idea why the professionals installed two 240v pumps or why they've been working for years then? Someone vaguely mentioned something over the phone about thinking you could also run the older ones at 120v somehow, but he didn't elaborate on it or confirm. Also, I should mention that I'm not positive that I'm using the multimeter correctly or in the right spots. I'm not sure if this helps or not, but the entire geothermal unit uses 3 groups of 2 switches at the breaker box. That would imply that the incoming connection to both pumps is 240v, correct? So I guess to get both pumps at 240v I would need 480v there?
 

Last edited by MrRobot; 04-06-21 at 11:05 AM.
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Old 04-06-21, 10:43 AM
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Zorfdt
Do you mean before they get to the first pump? It's been a while since I took Physics, but iirc, if both the pumps are measuring 120v in parallel, that means the input wire has a voltage of 240v, correct? Btw, it's entirely possible that I don't know how to use a multimeter correctly. I placed the black probe on the green grounding screw, and the red probe on the twisted together wires. It's a little hard to take measurements as I have to "purge" the unit to get it to kick the compressor on. The pumps only get power when the compressor is on.
 
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Old 04-06-21, 10:56 AM
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@Zorfdt
Do you mean the Ground/Neutral/Live terminal on the bottom pump? I also thought those were weird and that's what's throwing me for a loop. I wired them together the same as they were before, but before they both had the same connections as the top pump. Also, the installation manual confused me. It has the diagram for what looks like the new terminal under the "Multi-speed pump wiring" section, but this is a Single-speed pump. The figure under the Single-speed section looks like the old one. Here's a picture of it:



 
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Old 04-06-21, 11:34 AM
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Zorfdt
Ok so I just took some measurements. Starting at the input wire (very top, before the first pump), white wire to ground and black wire to ground both measures somewhere around 115v. Black probe on the black wire and the red probe on the white wire read somewhere around 200v. I got the same readings on the bottom pump. I'm assuming that second measurement is what you meant by "across." I understood across to mean on both sides of a resistor or something on the same wire. Sorry, apparently I should've paid more attention in physics class.
 
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Old 04-06-21, 12:31 PM
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Never mind. I just found out how to check if the impeller’s are running and both of them are, so it isn’t an electrical issue. I think it’s back on the HVAC side now. The pumps are running but the water isn’t circulating in which I’m told could mean some type of blockage or air pockets? You can delete this if you want, or move it to that other forum? Thanks for the replies though!
 

Last edited by MrRobot; 04-06-21 at 02:31 PM.
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Old 04-07-21, 10:11 AM
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Wanted to reply to your questions. I guess since you have them running, like you said, it's likely not an electrical issue - unless they are just under-voltaged and not running fast enough.

But now you're outside my expertise, I'll let the HVAC folks dive in more. I assume the pumps probably need to be primed - but not sure.
 
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Old 04-07-21, 07:32 PM
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Who ever wired in motor was a real klutz. Insulation should be remove so 3/4” to 1” of bare copper wire is twisted in wire nut for good connection

Is is easier to see when pump is powered on with 120 volt pilot light wired to it.

https://www.ebay.com/itm/5Pcs-120V-1...EAAOSwrx5UYdUu

Those wet pumps do not need priming. In fact should not be run "dry".
 
 

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