Do I need a circulating water pump on my boiler?

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Old 03-30-20, 05:24 PM
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Do I need a circulating water pump on my boiler?

I have a old hydro therm HC 165 hot water boiler. My Bell and Gossett circulating pump was making noise when I checked it appears to come on making a hum sound. It looks like it spins for a moment and then stop working. It has some age to it So I really think it's time to replace but this been going on for a couple of days now and I'm still getting heat even to the 3rd floor level of my home. I always thought the pump main purpose was to pump the hot water to reach the 3rd floor baseboards. Can someone explain to me? I don't know I was thinking maybe because the temperature outside is around 40 degrees that the you would get the heat without a pump. Maybe I don't need a pump? Thanks in advance.
 
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Old 03-31-20, 02:51 AM
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Since the baseboards on the third floor are being heated by the water from three floors below, the circulating pump is working. If the pump hum is bothering you, change the pump. Yes, you do need a pump. To prove it, disconnect AC power to pump motor and see how much heat you get on the third floor or anywhere in the house if there is only one circulating pump for all three floors..
 
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Old 03-31-20, 05:42 AM
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Okay this morning I am feeling a difference. It seems to be taking longer for my baseboard temperature to heat up and my basement baseboards are not going higher or lower but maintaining the same temperature. I have separate thermostats that's how I am able to tell the differences. I will try and change the pump myself but I am having trouble identifying the model pump being that the printing on the pump has really faded. I know it's a Bell and gossett pump. Do anyone know which pump would be a good fit for my Hydro Therm HC 165 hot water boiler in a 3 story house? I have include a picture of the boiler and the pump. Also meantime should I go head and disconnect the power from the pump because I honestly think it's not spinning but just making humming noises.
 
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Old 03-31-20, 07:28 AM
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rock13979 pump may be a B&G Series 100 that was widely used in residences.

A far better choice is Grundfos Alpha2 pump @ $175 with auto sensing of pressure and flow that adjusts automatically to changing system conditions. Uses 50% less electricity, and has LCD display of GPM and power. Literally plug and play.... has 7 selections of for pressure and GPM. Left powered on Alpha2's will idle until various zone valves open then adjust for flow needed.

https://www.supplyhouse.com/Grundfos...w-Terminal-Box

If rock13979 makes any changes to system, zones or adds them, Alpha will automatically adapt. Would recommend adding ball type isolation valves to facilitate pump servicing.

For rock13979 three story house the B&G 100 is fully adequate. The widely used Taco 007 may not be and the characteristics cannot be changed, buyer beware!

https://www.supplyhouse.com/Bell-Gos...Pump-3540000-p
 
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Old 03-31-20, 08:28 AM
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Thanks for the input doughess. Wow the Grundfos Alpha2 pump you recommend looks so much advanced and the price is much cheaper than the Bell and Gossett pump. I will probably purchase it but I will allow a little time to see if anyone else will respond on forum with their suggestions. Although my pump is located in a hard to work location it looks like somewhat simple install. Any advise on installing like draining water from the boiler etc.? Also if I go with the Grundfos would I have the change the flanges and if I stay with the B&G would the flanges be a direct fit? reason I asked it look like this old pump been on here for a long time and with limited space to work it might be a nightmare for me to change the flanges. I guess that is decision I would have to make.
 

Last edited by rock13979; 03-31-20 at 09:42 AM. Reason: add more text
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Old 03-31-20, 10:17 AM
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This another case on DIY.com where it is cheaper and better to replace old with new technologies. I am old timer but spent my career in high technology world. For many reasons new ways are often more practical and offer other benefits than just quick fix of old way.

Picture does not show things clearly. Think your best approach is to cut off 2 + foot of pipe rising from top of B&G. Make whole new assembly with drain at bottom, ball valve, flange, Alpha pump, flange, ball valve, upper system drain valve.

B&G 100 and Alpha flanges are same. I use stainless 3/8" screws & bolts.

It will make your future life easier. Plan now for old age. Been doing it in my home for 50 years and is paying off.
 

Last edited by doughess; 03-31-20 at 10:33 AM.
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Old 03-31-20, 11:04 AM
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Thanks for the help. Sorry the picture doesn't show behind but looking at it I think I might have a good chance of removing it by soaking the bolts for a day or 2 maybe applying some heat and then taking the motor and bearing assembly apart I believe that will give much more room to work. looks like the top bolts is not the problem its the bottom ones. I have to check the weather to see when the weather will be the warmest so if I get stuck we won't freeze if no heat temporary.
 
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Old 03-31-20, 12:03 PM
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It might be easier to remove bottom and top pump flange bolts, remove pump, then unscrew remaining upper pipe.

On work bench make new assembly with flange at bottom. From picture 3/4” fittings seems all that is needed.

When assembly (including Alpha pump) is completed, thread top pipe fitting into where original pipe went.
 
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Old 03-31-20, 12:05 PM
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Have you checked the coupling between the motor & bearing assembly? Your problem could be as simple as a broken coupling. Certainly worth a look before replacing the pump.
 
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Old 03-31-20, 12:37 PM
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rock13979: I always thought the pump main purpose was to pump the hot water to reach the 3rd floor baseboards. Can someone explain to me? I don't know I was thinking maybe because the temperature outside is around 40 degrees that the you would get the heat without a pump.
Hydronic Heating System Basics: Boiler heats water and pump circulates it through elements/baseboards. Cooled water is returned to boiler. System is designed, and pump selected to deliver xxx btu/gallon/hour at design temperature, commonly 0F. Boiler max water temp is usually 180F because higher results in boiler scaling. To avoid condensation 133F minimum temp.

B&G Series 100 was great classic pump, I nursed one for many years. Am happier with the Alpha.
 
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Old 03-31-20, 12:37 PM
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R,
Your current B&G pump has 3 replacable parts that could be causing your problem. A BEARING ASSEMBLY, COUPLING and MOTOR. Each one can be changed individually without removing the pump from the piping. You do not have to replace the entire pump if one of these parts go.

As Grady pointed out it could be as simple as a broken coupling or a frozen bearing assembly or it could be a bad motor. The motor and bearing assembly require annual oiling with #30 oil or equivalent. Just a few drops as over oiling is just as bad as no oil.

On another note these pumps have become very expensive and in my opinion unless it's only a coupling not worth repairing with the newer pumps and technology now available. With a little more work initially I think it pays off in the long run if installed properly.

That being said the Grundfoss Alpha2 that doughess recommended is a very good choice if you have multiple zones and self adjusts to only work as hard as it needs to. There are cheaper pumps that will work but you must match your current pumps specs with a new one where as the ALPHA2 covers a multidude of sins.

The flanges on both will match but more importantly is the distance between the flanges must be the same. It looks like you have black pipe which is fine under ordinary circumstances.

The distance between the flanges on your B&G is 6 3/8" and the ALPHA is 6 1/2". If you have no movement in your pipes at all it may not fit without repiping. Remberber besides the pump you also need to get gaskets in there. Just a thought. Ordinarily this is not a problem but with yours it doesn't look like the pipe can be moved at all.

Just a thought, hope this helps a little.
 
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Old 03-31-20, 02:29 PM
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Grady and spott you make a good point. I was going to take the B&G apart anyway to help with the install of the Grundfos Alpha2 pump. before I buy I will take a look to see if it could be repaired. I never took apart a pump before so as I go I will post for assistance.
 
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Old 03-31-20, 02:59 PM
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Do you guys think it would be a good idea to leave the old casing connected and just buy another B&G 100 take off the new casing and reconnect to the old casing on the pipe. It seems it would save me a lot of trouble trying to replace with a complete unit.
 
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Old 03-31-20, 03:22 PM
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The old casing/journal box is both a source of leaks and place to build points of blockage. Then extra gaskets can leak. It is just easier to replace whole thing at one time.
 
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Old 03-31-20, 04:56 PM
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I'm not sure what you mean by casing unless you are talking about the VOLUTE which is the part that connects to the 2 pipes. You may not have to go that far. The part that is bolted on to the volute is the bearing assembly which has the impeller on it. If that part spins free and does not leak you do not have to remove that either and therefore you do not have to drain the boiler.

The next part is the coupling which connects the shaft of the bearing assembly to the shaft of the motor. If this is the defective part you can just replace the coupling by removing the allen screws which hold the coupling to the 2 shafts with an 1/8" T HANDLE allen wrench. Then of course the last piece of the puzzle but what must be removed first is the motor which just bolts on to the bearing assembly.

That was one nice thing about these old pumps. Unless it was a bad bearing assembly you never had to drain the water from the system. The new pumps today which are called wet rotor pumps are 1 piece and water actually runs through the cannister so if defective the system must be drained unless isolation valves are installed before and after the pump which is highly recommended.

To answer your initial question, in my opinion and doughess mentioned, if you've gotten that far change the whole thing if possible. Start fresh with new gaskets and new pump. If it were me and were replacing the whole pump I would put in the ALPHA2 or similar new style and eliminate the need of couplings and bearing assemblies that can go bad.

Just my opinion.
 
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Old 03-31-20, 05:53 PM
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Rock: You said earlier (post #3) that the motor just hums. Does this hum just last a few seconds or is it constant as long as the thermostat is calling for heat? If it is constant, I'd say there's a 99%+ probability the problem is the coupling which can be replaced for about $10 and 15 minutes labor, even for someone whose never done it.
 
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Old 03-31-20, 06:18 PM
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Seems replacing entire assembly is favored. Here is simple, easy way to make temporary upper connection.

Remove old unit.
Assemble new unit.
Cut off pipe at pipe above old pump level so there is room for new assembly.
Install new assembly, bolting pump flange at bottom.
At nipple on top of assembly, use high quality, hot water, auto radiator hose for sleeve coupling with 4 clamps to joint it to old upper pipe.

Water pressure and temperature similar in both auto and heating systems. If worried about code later change it.
 

Last edited by doughess; 03-31-20 at 06:47 PM.
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Old 03-31-20, 06:32 PM
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If Rock wants to spend $200 & a lot of labor vs. $10 & 15 minutes, that's fine. Just trying to save the OP time & money which is generally why people do a job themselves.
 
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Old 03-31-20, 08:26 PM
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okay I think I will start with checking the coupling to see if it's broke like grady stated. If it's not broke I will continue on to replacing the pump with the Grundfos Alpha2.
Spott stated:
The distance between the flanges on your B&G is 6 3/8" and the ALPHA is 6 1/2" So I might have to re pipe. But I might consider Doughess idea about cutting the pipe and adding a hose instead of re piping.
 
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Old 04-01-20, 12:15 PM
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The coupling was broke! I brought one for $10 and put it on but that didn't fix the pump. It made noise and then stop turning the motor was hot even though it was not moving. It could be the motor but that cost the price of a pump So I will pickup the Grundfoss Alpha2 pump and work on installing it.
 
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Old 04-01-20, 02:18 PM
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Most likely the bearing assembly is siezed especially if it hasn' t been oiled in a number of years. For the cost of a bearing assembly, you're better off with a whole circulator. Easy to check if you really want to.
 
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Old 04-01-20, 03:28 PM
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Yes Grady it could be the bearing assembly. I had the house for 5 years and probably started oiling it a year ago and I know the previous owners never oiled it themselves. I will let you guys know how the install went when I do it. Although the pump is not working I am still able to get some heat it just takes twice as long to heat up and being that it;s not below freezing right now I am able to manage.
 
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Old 04-05-20, 03:10 PM
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Hey guys I picked up The Grundfos ALPHA2 15-55F I was down by the boiler sizing it up I noticed my flanges on the B&G face north to south and the Alpha2 15-55F flanges face east to west If I install it the controls and display will face the boiler with little room to see or control it. Did I get the wrong model? Should I have got this model The ALPHA2 15-55FR https://www.supplyhouse.com/Grundfos...Rotated-Flange Can I turn the flange to face the opposite direction? The bottom flange allows to be position in any direction The top would have to be turned. Another problem I turn the knob to drain the boiler to see how tight it was when I turn it back off it continues drip. Do I have to replace that too.
 
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Old 04-05-20, 03:27 PM
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Your boiler drain valve probably has a rubber washer on the disc. That could be replaced - but it will of course require draining the boiler, which you may be going to do anyway to replace the pump. You might just replace the boiler drain valve with a new one - they are inexpensive, and many hardware stores stock them. Get a name brand, such as Mueller/B&K. Chances are, your valve is a 1/2" brass with a garden hose coupling. No need for a lead-free version in boiler heating service. If you want to avoid replacing the valve, you can install a threaded cap on it.
 

Last edited by gilmorrie; 04-05-20 at 03:29 PM. Reason: cap idea
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Old 04-05-20, 05:37 PM
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If you don't want to try to turn the flanges on the pipe, return the circ you got & get the rotated flange model.
Regarding the boiler drain: Get a brass hose cap with a washer. On a boiler that old, there's a chance the valve could snap off when you try to change it. If that happens it becomes a real pain.
 
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Old 04-06-20, 08:59 AM
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A brass hose thread cap will avoid removing the drain valve. If you wish, you can replace the rubber washer without removing the valve - unloosen the packing nut and pull the stem out of the valve.
 
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Old 04-06-20, 11:59 AM
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I have the new pump now. I am working on it now. can someone tell me which side the check valve goes in? I was told the side where the inside is smooth.
 
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Old 04-06-20, 12:04 PM
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I just tried both sides it seems the check valve can only fit in one side of the Alpha anyway.
 
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Old 04-06-20, 05:01 PM
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I am stopping for tonight.I will start back in the morning. I didn't think it would give me so much trouble. screwing the bolts is like hell not much space to get a wrench to them. as I tighten the bolts I see the heads are smaller for the new pump and were making there way though the opening. tomorrow I will try adding some large washers on the bolts are buy some new bolts with bigger heads to prevent that. It's looking like the top pipe will probable be too long I was trying to lift it over and on to the pump but I am nervous I might damage one or more of the connecting pipe try to lift to much on it. I am considering cut the pipe connect the flange part to the pump and reconnecting with a rubber sleeve coupling.
 
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Old 04-07-20, 08:23 AM
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Usually circulator bolts are 7/16" x 2" long with a 5/8" head & the nuts are 11/16" hex.
Personally, I wouldn't use a rubber coupling except in a dire emergency & then only until I could get the parts to do it right.
 
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Old 04-07-20, 08:41 AM
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I am working on it now. I made progress. After shining a bright work light on the pump I noticed it's a slot where the bolts go to keep it from turning while tightening.(no need for 2 wrenches) I thought the bolt head was too small and was slipping though the flange. I am able to tighten the bottom bolts but left them a little loose until I can get the top pipe in line with the pump flange. after using a little muscle I notice I have more room than I thought to lift the top pipe onto the pump. In a few minutes I will try and lift the top pipe onto the pump without damaging . I will post back after.
 
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Old 04-07-20, 11:49 AM
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Okay the just finish installing the Grundfos Alpha2 pump. I checked for leaks and everything seems okay. I fired it up and it seems to be working. I assume I will have to bleed each zone and I am here knocking. After I eat something I will go back down and see if I can bleed it. It's been a while since I did it I have to try and remember the bleeding steps
 
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Old 04-20-20, 06:42 AM
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hey guys. the circulating pump is installed and working. thanks for everyone's help but the problem i am having now is pipe banging and the pressure relief valve is opening occasionally because of high pressure. It was really loud this morning. I cut it off and after breakfast I will look into bleeding it again maybe there is still air in the system. From what I see now the banging seems to be from my 4th zone which is the one that is used for the 3rd floor. I know banging is usually from air but this is the first time with the banging the pressure relief valve is opening. I was told maybe it could be the thermostat is set to high. May be with the old B&G pump it was able to sustain a higher temperature. What is the normal setting 180?
 
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Old 04-20-20, 03:42 PM
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If your relief valve is discharging, it's likely the expansion tank has lost its air cushion - not caused by air in your system. There are stickies above that cover this problem. 180 deg is OK, but you can drop it by 5-10 deg. What does your boiler gauge show for pressure and temp?
 
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Old 04-20-20, 04:52 PM
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I check the temp on the aquastat and I had it set at about 195. I adjusted to 180-185. I went ahead and bleed the system again. so far everything seems to be okay. my pressure is about 12 psi . it's not cold so no heat is on now but later this evening I will crank it up to see if it's still good. If not I will start looking at the expansion tank for the solution.
 
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Old 04-20-20, 05:47 PM
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If you are at 12 psi cold pressure that's fine. What's not fine is your relief valve going off when your boiler is in use. Your relief valve is set to go off at 30 psi and your pressure should never climb from 12 to 30 unless your expansion tank has a problem and leaves no room for the heated water to go when it expands.

I would guess you either have a bladder problem with an extrol or a full tank if you have a steel tank. Either way there is no place for the water to expand so the built up pressure reaches 30 and blows the relief valve. Temp really doesn't have anything to do with it if everything is operating as it should.
 
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Old 04-20-20, 05:50 PM
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195 deg is too high. The aquastat setting is often unreliable. The boiler gauge might be more accurate? I agree with Spott - the relief valve problem is most likely the expansion tank, certainly not air entrained in the system.

You've fought the good fight. Maybe time to call in a real pro whose references you've checked?
 
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