Replacing Taco 007 F5 circ pump need help

esandma

Hi All -
I'm replacing a Taco 007 f5 pump that has failed (on a Weil-Mclain/Carlin setup with hot water tank off boiler). Currently the pump motor is in the vertical position and is installed in the feed line going away from the furnace (toward the baseboards).

I plan to mount the pump so the motor is horizontal (if I can spin the flanges 90 deg). But I'm wondering about the placement of the pump in the feed line rather than the return line to the furnace... I always thought these (and most) pumps like to push fluid rather than trying to pull it so that the pump should be in the return line, not the feed line. And, can I mount the replacement pump as it is now or should I try to rotate the flanges for horizontal mounting?
Any help would be appreciated.

Ironman

The pump Must be horizontal.

When you say "feed line", I assume you mean the supply line. And yes, that's normally the correct place to mount it in a system that's directly pumped from the boiler.

Technically it should be immediately down stream from where the expansion tank connects to the system, "pumping away" from it.

Get Dan's book with that title from the onsite store for the technical explanation.

Gilmorrie

Yes, the motor should be horizontal. But, if it was working well before, don't worry about pumping toward the boiler and toward the expansion tank. For decades, B&G recommended that arrangement, and millions were successfully installed that way and are still working fine, including my 65-year-old boiler.

A pump doesn't know whether it is pushing or pulling. It just cares about its suction pressure and its differential pressure.

Gordy

No the pump doesn’t know, but air does.

Mark Eatherton

Gilmorrie said:

Yes, the motor should be horizontal. But, if it was working well before, don't worry about pumping toward the boiler and toward the expansion tank. For decades, B&G recommended that arrangement, and millions were successfully installed that way and are still working fine, including my 65-year-old boiler.

A pump doesn't know whether it is pushing or pulling. It just cares about its suction pressure and its differential pressure.

The reason that B&G and almost everyone else had their pump installed on the return was due to poor rag seals. We haven't had rag seals on pumps since, forever... at least not in the last 42 years. Not putting the pump so it is pumping away from the expansion tank and the boiler will result in air binding of radiators/baseboard.

The other reason that it didn't matter was because all of these old school pumps were a flat curve pump, working in a system with little to no major pressure drop. Todays systems are completely different, and all pumps MUST pump away from the expansion tank connection, and preferably, away from the boiler.

So, if you want an air free, relatively trouble free, quiet system, pump away from the expansion tank connection and the boiler. But if you want constant air noises and circulation problems, then follow Gilmorrie's suggestions.

ME

hot_rod

pumping away from the expansion tank is preferred.

Many of the newer mod cons prefer pumping into the boiler so the boiler enjoys that ∆P provided by the circulator.

It is possible to pump away from the PONPC and into the return.

Keep the air separator at the boiler supply, the hottest fluid location.

esandma

Okay... thanks. Interesting discussion (at least for me). I have one other question. There are no shutoffs on either side of the pump. When I remove this pump, how wet can I expect to get? Will the entire system drain out? I've included a photo of the system:

Harvey Ramer

Make sure the power is turned off to the boiler for a few minutes.
Verify all 3 zone valves are closed.
Close the valve or valves on the boiler return.
Close the valve for the boiler make-up water (fill valve).
Drain water from the boiler drain until the pressure goes to zero.
Set a 5 gal bucket under the pump and loosen the flange bolts. Crack the flange seal and let the remaining water drain in the bucket.
Remove pump and clean the flanges still on the system.
Install new pump with rotated or universal pump flanges to allow for correct motor orientation. If needed, loosen bolts connecting motor to pump volute and rotate motor body to the correct orientation.
Turn fill valve back on.
Put system back in operation.

unclejohn

If you have a single story house like a rambler you can just keep the power off and do not open zone valves. Shut off your inlet water supply and open the drain valve at the bottom of the boiler and watch the pressure gauge, when it gets to zero let it run a bit then shut the boiler drain. Get a 5 gallon bucket a place it under the pump. Loosen the flange bolts and you should be able to swap out the pumps with out filling the bucket. If there is to much water drain some more and try again.

unclejohn

Also might be a good time to swap out the extrol tank if you haven't done it in a while. If you provide a picture of the pipe connecting to the boiler there may be a spot to add a shut off valve for the next pump change.