Help determine the right circulator pump needed

Lev77 · October 2018

Hi all, thanks for reading,

We recently got a building of 4 stories and 4 1BR apartments on each floor.
The building has hot water heating using 3 peerless flex heat boilers (also supplying domestic hot water).
2" Water copper pipe comes out of those boilers to a ring, and from that ring goes out to the heating loop (1 1/4") that goes around the building and back to that same ring.
About a foot from when the heating loop starts, there's a circulator pump, Bell and Gossett.
In the months after last winter, the pump started leaking, and finally a few weeks ago it shorted the circuit so now it needs replacement. The exterior is all corroded so I can't see the exact model.

I had a plumber come in to replace the pump, and he offered me to get the pump myself if I can get it cheaper.
He gave me a part number. Before I ordered, I checked the specs and it was a 2 1/2" pump.
I asked him to confirm and he said, yes it's the part number he was given so I should get it. So I got it.

This is the pump corresponding to the part number he gave me:
https://www.supplyhouse.com/Bell-Gossett-102218-1-4-HP-2-1-2-Circulator-Pump-5604000-p

Now the plumber tells me it's the wrong pump etc because he doesn't know if it would cause issues on a 2" size pipe on one side and 1 1/4" loop on the other side, and he doesn't know where to get 2 1/2" fittings, and and and..

I asked him why he gave me that part number, he said he described the building to his supply house and they looked it up on some chart and that's the pump they gave him for a certain head pressure.

I researched online and this is a pump that has a 2" connection:
https://www.supplyhouse.com/Bell-Gossett-102214-1-6-HP-2-NFI-Circulator-Pump-5603000-p

Given 2" pipe on the supply side of the pump and 1 1/4" on the closed heating loop, and these 3 boilers etc.
And assuming the right fittings can be bought etc, will the 2 1/2" pump improve anything in getting good heat throughout the loop (without causing problems)?
Or should we go for the 2" pump, same model that was there before because that's the "safest" option?

Would greatly appreciate your advice, thank you

HVACNUT · October 2018

There has to be numbers on the existing circ that you can cross reference with. There's numbers everywhere. The motor, bearing assembly, body.
The circ the plumber recommends is 1/4 HP. The one your asking about is 1/6 HP. So that's important.

Get more info and a pic or two and we'll try to help.

It could be just a bad bearing assembly and that by itself can be replaced. Along with the coupling. That's to say if the existing circ is not a dinosaur.

If it's not worth a repair and a replacement is necessary, a wet rotor pump would be a better choice.

And forgive me if he's the whole package, but a heating contractor is needed, not "just" a plumber.

Lev77 · October 2018

Thanks HVACNUT, I would agree, he is supposed to be a heating specialist. Apologies to all those in the profession, no offense intended.

Turns out the existing is indeed a 1/6HP.

Here are some pics of the existing.
Seems like the existing is a match for the second pump link.

So now the question is, should I return the 1/4HP pump or is there a way to make use of it instead and benefit the building?

Based on the description of the piping and the building, what's the recommendation?

Lev77 · October 2018

And sorry I missed this, what's a wet rotor pump? Would it fit in and work the same way? Can it handle the building?

EBEBRATT-Ed · October 2018

I wouldn't use a wet rotor. Do this. Find a supply house that sells Bell & Gossett Pumps. Take the pump their. Have them call the B & G rep while you are there. Give him the information (flange size, pipe size, motor horsepower and voltage etc and any #s) on the pump and he will match up the correct pump

Lev77 · October 2018

Thanks Ed, I feel a little bit more confident now that I found the pump that matches the pump that was there. I think now I'm trying to determine whether the larger pump that I ended up ordering would work better or I should get a pump matching the existing. Any thoughts?

hot_rod · October 2018

Are you sure the original pump was sized correctly? If an original design is still around you could confirm that, or measure the performance of the old one, maybe not possible now.

Or calculate and "reverse engineer" the piping circuit.

To correctly size a pump you need to know:
type of fluid
GPM required
pressure loss of the circuit

There are some nice electronic, high efficiency ECM pumps available that let you "see" and adjust operating conditions, like the Grundfos Magna. A pump like that could be dialed in to the exact conditions, and flow you need.

Lev77 · October 2018

Thanks Bob, I'm not entirely sure if the original was sized correctly. Also not sure when it was installed but unfortunately the design doc is not available to me that I know of.

What controls this circulator pump right now is a tekmar 268 controller. I think it knows to turn the pump on and off. Not sure if it knows anything else, it could be.
I don't know the requirements for the electronic pumps.

Now I've said a few "not sure" and "don't know", but I'm happy to do some research, maybe with some guidance if you'd be willing.

HVACNUT · October 2018

> @EBEBRATT-Ed said:
> I wouldn't use a wet rotor.

I'm not experienced at all with piping design of typical 4 story buildings, or much commercial except the light stuff. Perimeter loop with zones valves on the branch loops?

Assuming the correct HP, head, curve are known, and with a new magic circ hitting the market every 6 months, why not a wet rotor pump?

hot_rod · October 2018

Lev77 said:
Thanks Bob, I'm not entirely sure if the original was sized correctly. Also not sure when it was installed but unfortunately the design doc is not available to me that I know of.

What controls this circulator pump right now is a tekmar 268 controller. I think it knows to turn the pump on and off. Not sure if it knows anything else, it could be.

I don't know the requirements for the electronic pumps.

Now I've said a few "not sure" and "don't know", but I'm happy to do some research, maybe with some guidance if you'd be willing.

Yeah, we would need to know more about how the building is piped? Sounds like just one circulator pump and zone valves at every unit with ? fan coils, fin tube, radiant, as heat emitters.

Domestic hot via an indirect tank, or heat exchanger?

Lev77 · October 2018

Thanks Bob,

These are the boilders + Domestic hot via indirect tank (I think) + expansion tank etc etc:

This is where the heating loop starts:

You can see a disconnect in the pipes which is where the pump used to sit.
If you follow left from that point (pipe: 1 1/2"), after the air relief valve you see a T and the pipe rises then another T to right and left. The pipe gets reduced to 1 1/4.

In the apartments, there's a valve connected to thermostat (it's an old setup - this thin wire between the thermostat with numbers 1 through 5 (as opposed to temperature) and the heating pipe).

Does that give you some idea? Any other info that I can get?

hot_rod · October 2018

So it looks like the boilers are all tied into a primary loop with closely spaced tees, ok. A Taco circulator on that loop. Two takeoffs for the space heat, all looks fine from what I see.

Confusing is the next pic, looks like 3 air separators all bunched together, one Spiro and two scoop type. I assume that is a bull head of some sort with flow in two directions?

The missing pump flowed towards the Spirovent at the tee and two different directions? Looks like someone was trying to correct an air problem?

Was the system working fine before the failed pump? Any back history on who of what has been done to the original system?

What type of heaters in each unit, fan coils? You need to try and get an estimate on GPM and pressure drop thru the heat emitters.

Lev77 · October 2018

Here's what I understand in the 2nd picture:

The flow in 2 directions possibly suggests that the front of the building (8 apartments) is piped separate from the back.

In the apartments there are baseboards only. The same pipe that starts in the basement ends up in the same form in all the apartments, I'm not sure what diameter, possibly 1".

The system was working okay last winter that I know. Tenants on the 4th floor said they were not getting as warm, but I'm not sure if it had to do with pump not being sufficient or the roof being old (which I replaced this year) and letting all the heat out, or something else. When I touched the baseboard pipe it was hot then. In short I have no reason to think that there was any problem in supplying heat to the pipes. But I don't live there so I don't know.

The pump itself was just hanging by the flange screws, without any support to the motor. I'm not sure if that alone caused the leak from the pump, but that's what the plumber said.

So what is the pressure drop in this case? Or do we need more information?
How do I measure or estimate GPM?

Zman · October 2018

How many square feet is being heated? What is the farthest distance from the boiler room to the farthest heater? What type of heaters do you have.
If I am understanding you correctly, you have a 1 1/2" pipe that tees off to (2)- 1 1/4" pipes?
It is very likely that they designed the system for 4 ft/sec. That would translate to 25 gpm for 1 1/2" pipe. https://www.onicon.com/wp-content/uploads/0868-5-Velocity-to-GPM-Chart-2-sided-04-18.pdf. If your existing circulator is the 2" 1/6 hp, your existing head would be around 10'. https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1332957606422/73542_PROD_FILE.pdf.

Unless there is something unusual about your system, I would be very surprised if this circulator would not be a good fit. https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Taco-VR3452-HY1-FC1A00-Submittal-Sheet.pdf.

You would need more details about the system to know how to set it up.

hot_rod · October 2018

This is going to to take some time and number crunching to determine what the original design was, why the changes and modifications. Perhaps your plumber has the knowledge and experience to do the system analysis. With piping not visible, it will be a guesstimate at best.

If the previous pump worked, was noise free and provided adequate heat... Or install one of the new variable speed electronic pumps and play with the settings to dial it in.

Ideally you want to move sufficient flow with the least energy consumption. the new pumps have digital screens to show you exactly what is going on, gpm and head.

Here is an example of how the new electronic pumps work and can auto adjust to the system. Most all pump brands offer these type of pumps now.

https://www.youtube.com/watch?v=kg7DIv8AL3w

Zman · October 2018

Older buildings with no "as builts" will always be a SWAG at best. The beauty of the new generation ECM's is that if you SWAG in the middle of their operating range, you can dial it in once in the field. My experience has been that you can usually run the circs lower than what the math tells you...

Lev77 · October 2018

Thanks both.

I know the B&G pump has just 2 wires, and the controller turns it on and off.
Will the Viridian pump work the same way?

Can it handle pushing the water up 4 floors and about 20-30' in every direction from the center?

Zman · October 2018

The vertical does not matter as what goes up must come down (think Ferris Wheel). It sounds like you have around 100' of piping each way.
What type of radiators?
Have you been able to determine the model of the existing circ?

Zman · October 2018

Looking back at your pictures, you have a 1/6 hp motor. It is likely you have the model 2. https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1332957606422/73542_PROD_FILE.pdf

You should be able to measure it to be more certain. In either case, the Taco Veridian VR3452 would be a suitable replacement for any of the 1/6 hp models.
It will come with a cord that can either be hard wired or plugged into your 120 volt circuit.

Lev77 · October 2018

There are just baseboards throughout the apartments. Am I misunderstanding what you're asking in terms of Radiators?

The existing pump is a 1/6 horsepower B&G, this one:
https://www.supplyhouse.com/Bell-Gossett-102214-1-6-HP-2-NFI-Circulator-Pump-5603000-p

Lev77 · October 2018

Just seeing your post before my post (I missed it while typing on my phone).

It's definitely a 2".

@hot rod and @zman thanks for helping thus far, really appreciate it.

My last question (for now) after all your help, is:

The existing pump was wired to a tekmar boiler controller, that decided when to turn the pump on and off just as it decided when to turn the boilers on and off, turn on the air inlet etc.

This Veridian pump, can it operate this way as well? In other words, when the controller decides that it's time to turn on the heat, it would turn on the current to the pump, and when it decides heat is not needed, turn it off.
Sorry if the question is ignorant, but if the veridian can operate this way then I can just move forward with it.

If there's anything else you feel I should cover prior, would be great to know about it.
And thanks again!

Zman · October 2018

If you buy the Taco circ and set it to constant pressure 10' of head it will circulate almost exactly like the one you have and use less energy. If you get geeky and experiment with the other settings, you will see greater savings. Yes, you can wire it into the tekmar like your existing pump. You will want the 115 volt model.

Lev77 · October 2018

Thank you very much, I'm going to go for this pump. So I need to reduce from the 2" pipe to 1.5 which is the max flange size for the Veridian.

Lev77 · October 2018

One rookie question: what's the way to purge air from the heat Loop once the pump is installed?

Zman · October 2018

The circ uses a standard 2 bolt flange. https://www.supplyhouse.com/Webstone-50407HV-2-Sweat-Isolator-Flange-High-Velocity

As far as purging goes, if you system does not has purge valves installed, you will need to add them. Circ flanges are available with hose connections for purging.

Lev77 · October 2018

Thanks again.
I don't know if there are in fact purge valves. I will look.

Would this be one of those flanges that you mention:
https://www.plumbingsupplynow.com/heating/flanged-valves/webstone-isolation-flanges/swt-w-drain-rotating-flange/2-lead-free-swt-isolator-w-multi-function-drain-rotating-flange-51417whv?utm_source=google_shopping&gclid=EAIaIQobChMIwrSvi-_33QIVjJ-zCh0k2wYVEAkYDCABEgIxkfD_BwE

Also, would you be willing to share a procedure for purging with hose?

Thanks again, this is all extremely helpful.

hot_rod · October 2018

If you drained down the entire building, plan on spending some time getting it purged and running smoothly. You may need to go in all the units and bleed the baseboards.

ideally those central air purgers do the heavy lifting. Seeing so many on your system makes me wonder if it has had air problems in the past. One Spiro vent should be adequate, maybe some auto vents on the boilers and high points in the building.

The expansion an connection to the system is also critical for quick easy air removal, that too can be tough to locate on a multi pump primary secondary piping. Hard to tell from the pics how it is all piped.

You may want to find a hydronic pro to help with some of this, they have the tools and knowledge to get er done, check safeties, boiler combustion, venting, combustion air, etc..

Lev77 · October 2018

Thanks Bob, we did not drain the whole building.

.

We shut off the top valves, the ball valves on enter and exit the of the heating loop, and the ball valve of the return all the way to the left in the picture.

I just read a little about these air separators and eliminators.
So basically after installing the pump, I should let water fill that whole closed up section before opening the valves so that the water will replace the air that's there through the different air vents. Is that the idea?

I'll take more pictures of the system to help map all the components.

Maybe I should look for an expert, although in the area where we have the building it seems hard to find someone who is truly an expert - they use scare tactics to suggest improvements and end up getting me in bad and/or uncomfortable situations. But I am a technical person who can learn quickly, and it seems that the more complex stuff I'm better off learning by myself from people who seem more reliable and knowledgeable than what's available in that area.

hot_rod · October 2018

A can do attitude helps. You need some specialized tools to perform all the tests and adjustments to be sure it is safe and efficient. The boilers should be tuned, relief valves tested, LWC switches tested, confirm expansion tank condition and pre-charge, and balance that pump so it runs properly on it's curve.

Lev77 · October 2018

Thanks, appreciate it.

The relief valves I just replaced and tested on all of them.

LWC I haven't figured out where these boilers have that switch.
They seem to be fed directly from that loop above, 2" pipe going into them with pump, and 2" coming out of them. Must be somewhere under the cover. I guess one way to test is drain the water from one and somehow prevent it from getting filled back up while it's on and see if it shuts off automatically. What's a better way?

Expansion tank - I googled and this came up:
https://www.stevejenkins.com/blog/2013/12/testing-and-replacing-a-hot-water-expansion-tank/
Is that a good procedure for testing and confirming status?

When you say balance the pump, you mean physically with a level?

Question on the pump topic:
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Taco-VR3452-HY1-FC1A00-Product-Overview.pdf

I looked at the Viridian pump model suggested by Zman.
The flange size says 3/4 to 1 1/2.
Seems to me that I have a gap in understanding.
Zman mentioned that this pump uses a standard 2 bolt flange, and provided this link for a 2" flange:
https://www.supplyhouse.com/Webstone-50407HV-2-Sweat-Isolator-Flange-High-Velocity

If the flange size in the product spec of this pump says 3/4 to 1 1/2, does that not mean that I need a 1 1/2 flange?

Zman · October 2018

I would just buy the flange that matches the pipe size you are connecting to. You could buy 1 1/2" and use a reducer coupling.

Lev77 · October 2018

Thanks Zman, I guess my confusion was with the 2" isolation flange link you gave - if the pump has a connection diameter of up to 1 1/2, does that not mean the flange will mismatch the pump?

Again I am quite ignorant on these topics and can ask ignorant questions, appreciate the patience.

Zman · October 2018

The flange will have a reduction inside. There would be nothing wrong with using a 1 1/2" flange and then adapting to pipe size.

Lev77 · October 2018

Thanks, okay makes sense.

And yet another question before I press "Pay":

https://www.supplyhouse.com/Taco-VR3452-HY1-FC1A01-Viridian-Self-Adjusting-High-Efficiency-Wet-Rotor-Circulator-with-Communication-Module-Less-Flanges-Rotated-115V

Apparently there's a version of this pump with a communication module. Any experience with this? Costs another $300 but I'm tempted.

From the manual:
The communications module has a built in web server which allows you to access your pump directly from an existing
Ethernet network. Direct connection to a computer is also possible with a crossover cable.
The web server uses HTML pages to set/view:
• Regulation mode settings
• Regulation parameters (power, RPM, head, flow, efficiency)
• Relay settings
• External control inputs
• Current and previews error
• Pump statistics (power consumption, run time and other).

Zman · October 2018

That's the one. I have not tried the module. If you get one please report back as to how you like it.

Lev77 · October 2018

Thanks again @Zman , that pump is on the way.

@hot rod thanks also. I do have a question for you on the boilers. One thing I noticed recently, particularly after the plumber visited to remove the old pump, was that the boiler pressure relief valves were dripping occasionally (even with the new ones that I installed).

Today I checked, and in fact it does appear that the boilers are climbing up to 30PSI. The Tridicators show 30PSI, the valve starts dripping, then stops and the boiler stops too then.

I'm not sure if it has anything to do with anything, but I think the plumber shut off the valve to the expansion tank.

These boilers are providing DHW as well as heat, so they are still active. I assume the pressure building up to 30PSI is not normal.
Should I drain each of the boilers to see if there's any buildup inside? Any suggestions?

hot_rod · October 2018

Pressure will climb if there is no expansion connection, or the tank is waterlogged.

Lev77 · October 2018

@Zman, thanks again for your help.
I got the pump, and have put it in place with the isolation valves, tested for leak and purged the air.

Just need to figure out the wiring.
I sat and wrote a whole post here, just to realize that I was looking at the communication module and not the power port.
If anyone has any tips on wiring this thing I would welcome it.

Zman · October 2018

If it came with a cord, you can either cut the cord off and wire it like a regular 120 volt circuit or plug it into receptacle. If no cord, you will need to wire it yourself.

Do you have a picture?

Lev77 · November 2018

No picture yet but it's now working and working very well.

I'll post a picture this weekend.
Haven't gotten around to use the communication module, have a few things to take care of before that.
Thanks so much for the recommendation!

Here's a "thank you" line:
@hot rod_7
@HVACNUT
@Zman

Many thanks folks.

Help determine the right circulator pump needed

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