Boiler circulator pump leaking flange/gasket replacement

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rmcderm313

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Hi All,

I've got a leaking circulator pump on my boiler. It appears that the gasket has failed and the exposure has done some damage to the flange and possibly the pump housing as well. I'm certainly no plumber but I'm pretty handy, so I'm going to try and replace this myself.

Here is a link to photos of the setup.

https://photos.app.goo.gl/i43BN4ZNePdpaZBD9

My system is forced hot water. There are two other zone pumps that are away from this pump. These do have shutoff valves that I can close in case the heat system would drain back down through the boiler. I'm not sure if it would be I can close those.

I believe that the pump in question is the main hot water circulator which both pumps to heat the external hot water tank as well as pumps hot water on demand to the whole house. There is a shutoff between the hot water tank and the pump, so that's good to isolate it. My question is what is the best way to isolate this pump from the rest of the hot water pipes through the house, or whether I just need to drain the whole upstream system of hot water before replacing this.

After the pump there is an expansion tank, and then after that there is what looks to me to be a shut-off valve. Can I use this to isolate the pump? The are a few picture of this in the album, black with a square set screw (not sure what it's called).

I'm certainly going to replace the gasket and flange based on low price alone. The pump is $88 and looks to be in good shape. Not to mention I'd rather not get into re-wiring a new pump. What are your thoughts on whether the slight damage to the pump housing would compromise the seal. I think it's just the paint and very outside of the pump that has some corrosion.

Any advice is appreciated, both specifically to these questions as well as overall advice on how to go about this and things to watch out for. I know to turn off the electricity to the system and allow the hot water to cool before starting.

Here are some links to the specific parts involved from HD. Is it safe to assume that these gasket and flange kits are the right size or do I need to measure my installation specifically?

https://www.homedepot.com/p/1-25-HP-Cast-Iron-Circulator-Pump-007F5/205741246

https://www.homedepot.com/p/Rubber-Gaskets-2-Pack-BP396/202277432

https://www.homedepot.com/p/Plumbers-Edge-3-4-in-Flange-2-Pack-PECF075/205892462

Thanks in advance. If I haven't included a good picture of something that would help I'll take more.

-Rob
 
Doing a little more research it looks like the copper pipe coming into the input side of the pump is 3/4, but is using an expanding coupler to 1 inch. So I'll order the 1 inch flanges. When replacing the flange is it simply using thread tape and screwing it on?
 
The line that comes off the boiler to the BLACK calculator, which is in need of a new gasket and mating flange, is actually for the hot water tank as well as the feed to the house heating system. The inlet of that pump is what you see coming out of the boiler and it has no valve on it. That same line is going up to feed the house heating system, by way of that Taco Air Scoop and expansion tank. From there it goes through what appears to be a (black) Taco Flo-chek valve. I don't have enough experience to know whether we can rely on this valves check valve function. That is to say whether it will keep the house piping water from coming back. We'll come back to that again.

The bottom side of that calculator with the copper pipe does not show what you called, "an expanding coupler to 1 inch". It shows a 3/4" copper x threaded male adapter. (I believe that is what that pipe size is.) The top has the thread (3/4") iron pipe nipple. (No expanding coupler.)

The pair of circulators are on the return line from the house system and connects into the boiler, with a 1/2" water make-up line coming from the wall area.
So if the flo-chek valve can keep the water from coming back from the house piping, you should be able to shut the 2 valves above the 2 circulators to isolate the house piping water.

You must also shut the 1/2" valve on the make-up water line, as well.(Vertical line on wall with backflow preventor and pressure reducing valve on it.)

It's too bad you can't isolate that circulator from the boiler, however. But it looks like you can isolate the hot water tank from the boiler, with 2 valves. One on the feed to the tank(on circulator line) and one on the return to the boiler.

So If that check valve cooperates, you'll just have the level in the boiler to draw down to the bottom connection of that circulator.

You may have to explain what you were referring to talking about an "expanding coupler".
 
I made a few edits to my comments above, so you may have to read it again.:)

Another EDIT: BTW...you will likely find a flow direction arrow on those circulators.
 
Last edited:
Diehard, Thanks for the great response. Boy was I mixed up. I think your response has me straightened out now. Regarding the "expanding coupler", it looked to me at first like the pipe between the circulator and the water tank was smaller than the threaded connector, but I can see now that it is the same size. yes, the pipe is 3/4". So I'm clear on that as well. I really appreciate you taking the time to respond.

I'm sure I'll think of additional questions!
Thanks again!
Rob
 
rmcderm313 said:
Diehard, Thanks for the great response. Boy was I mixed up. I think your response has me straightened out now. Regarding the "expanding coupler", it looked to me at first like the pipe between the circulator and the water tank was smaller than the threaded connector, but I can see now that it is the same size. yes, the pipe is 3/4". So I'm clear on that as well. I really appreciate you taking the time to respond.

I'm sure I'll think of additional questions!
Thanks again!
Rob
Click to expand...
Sorry about that Flo-chek vs a tee with a plug, but there should be something further downstream to control the flow, to the best of my limited knowledge.

As far as the replacement flanges fitting, they should. It's a Taco pump and those flanges say they are designed for use with a Taco pumps. Plus I think they're fairly universal but I'm not a plumber.
 
Hi Guys,

I do have 2 Taco flo-check control valves. One on each of the two heating zones, basically at the end of the black pipe that the expansion tank hangs off. So there is about 25 feet of that black pipe, then the flo-control valves and then the copper pipes running to all of the baseboard heaters. Can anyone tell me if those flo-control valves will keep the water that is sitting in the baseboard piping from running back down to the furnace where the gasket needs to be replaced. If not, I suppose I'll just need to drain as much as wants to drain.

So my plan is to use the drain that is on the return pipe of the boiler. This being lower than the send/output pipe, I'm hoping that by closing the valves on the return pipes from the baseboard heaters, closing all other valves available, such as the water tank and the street supply, and then draining from that hose bib, the system will drain as much as needed and that pump can be removed without leaking any water. The hose bib is shown in this image in the upper left. If not you can see it in the album linked in the first post. It's the only hose bib close to the return on the boiler. My biggest concern is that the water doesn't flow freely through the boiler and that would leave un-drained water where the pump needs to be removed.

LPkJW0UmnyYpjsih_AevxyizjSe_v7VAN5i_fr01NhKCxIOB-BFnNiyHoizGaO7yi-qzBy0LvNiK3W9ODmcfYPSUwDQvzg1xDafvfQTTT66uM_3MNXuqST0sDw9CZubu8tApThrFPG7g4y-YK4kXbkV95iimRckl-dK7bEM990b9kNkQMrs_hM_tKrI7ZsDqEnE7C4ZzoIEb7_yT7WmzztfOmOGdolB9RV9fTZQsHXN5bHb8nJIgtivHuw5OsStU5QD6zhZoTDry9jaoyxmd18mj9IMR6OuoW1hphkWZzlnHY3P_URODDAYksRy9rNpLh0Qee2K6TNWX6Cs0DUIL2YOOI4E1ckMKHZOMSR6iHk2-IctnKnQUyH04LTJg-iAL2lwnxeqVcKX5ELfCeYz0NuNYW6xFzBVO4H8VYS_dpmTnXlhUHlFJ-Rj8ruODgdNU4R1QsadbehXdrbaa3b2YavHVioOcbhGAWzEZG4nzuTCxdTCIleaDeMvE2rdux2KUw8WxedjpAzv87xN_EUGk-F0bNYxXwTyLos7e11AB9An-8geiz9pyXFnBFtpFm2pJRYDaqYyU1yzKIZRxyG7SF6f7dQk701zLX_meh7NTqU-MPVTPwY0xiWkdVKNZbE4pLxqMY6Nj4AJ_59r1NC6s3baQMKSXFhb89Q=w671-h895-no


Once I'm done replacing the gasket and flange, I have some basic instructions for re-filling the system from the 'make-up' valve and bleeding air out. But if anyone has tips, tricks or great instructions I'd appreciate it.

Thanks for all of you help thus far.
-Rob
 
Sounds good to me.

"The Flo-Chek serves two purposes: It prevents flow from going in reverse direction from the arrow on the valve, and it prevents thermosiphoning when the pump is not running."
So if they're clean and working properly they should prevent back flow. But Like I said before, I have no experience with regard to them preventing back flow.

Since the drain connection leaves the boiler lower than the line leaving the boiler that connects to the subject pump, you should be alright. Draining may be a bit slow with the gurgling for air.

Of course, first thing to shut off is electric power.
 
Diehard & David gave you some good advice. Like said, turn off the electric and the water to the boiler system. Close the two ball valves
going to the water heater like Diehard said. I believe you are going to have to drain the boiler system. The taco pump, flanges and gasket & bolts are perfect. It will fit in where the other pump is. When you are ready to fill the boiler back up after your repair you can close the two ball valves above the two green taco pumps and then one at a time put a hose on one of the four hose bibs and then open it up until you have all water coming out and no air, then close it up and do the next one. When all four are done open the two ball valves above the pumps back on. After the boiler is all filled then open your valves to the water heater. Turn boiler on and get it heated up and then make sure all four pipes where you bled at are hot. If any of them are not hot then re bleed them again. Can you take a good picture of the pressure reducing valve where you turn the water on and off for the boiler as I want to see if you have a fast fill option.
 
TomFOhio said:
Diehard & David gave you some good advice. Like said, turn off the electric and the water to the boiler system. Close the two ball valves
going to the water heater like Diehard said. I believe you are going to have to drain the boiler system. The taco pump, flanges and gasket & bolts are perfect. It will fit in where the other pump is. When you are ready to fill the boiler back up after your repair you can close the two ball valves above the two green taco pumps and then one at a time put a hose on one of the four hose bibs and then open it up until you have all water coming out and no air, then close it up and do the next one. When all four are done open the two ball valves above the pumps back on. After the boiler is all filled then open your valves to the water heater. Turn boiler on and get it heated up and then make sure all four pipes where you bled at are hot. If any of them are not hot then re bleed them again. Can you take a good picture of the pressure reducing valve where you turn the water on and off for the boiler as I want to see if you have a fast fill option.
Click to expand...
I looked back at the original pictures and zoomed in on a couple that may help.
prv 3.JPG PRV 4.JPG
 
Thanks Diehard. Not familiar with that one. I'm used to the B&G type with a fast fill option. You are able to by pass the set pressure and fill the boiler
faster. You just can't let it get up to 30 lbs or it will pop the relief valve. Ask me how I know that!!! Lol. He can still do it like I said
without fast filling it. It just takes longer. Maybe one of the other guys or gals are familiar with this PRV.
 
I am not familiar with it but when I looked it up based on its appearance, reference was made to a purge function. So between that and the fact it has that lever, it appears that it may have a quick fill feature.
 
Thanks so much guys. I feel ready to make this attempt. I will definitely post updates when I make the repair.

-Rob
 
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