Taco pump on return side

Steve M_2

Well you already have the boiler and two pumps so you're only a couple components away from the ultimate in comfort. With a variable speed injection mixing control you can nail the comfort level and provide boiler protection. You can use a Taco PC 705 or a Tekmar 356 and get another pump for your injection pump and a few extra fittings and wiring and you're there!

Pedro_3

Taco Pump

My hot water water boiler is about 25 yrs old and has the Taco pump installed on the return side. Would this configuration have to be changed when the new boiler is installed and what would be the difference?

Thanks

Brad White_203

Huge

The biggest part is not so much what side of the boiler it is on, but where the expansion tank is connected.

Too often what you describe would have the circulator on the inlet side of the boiler and the expansion tank on the outlet side of the boiler, whereby you are pumping TO the expansion tank.

What is better and less invasive in that case is to relocate the expansion tank connection to the inlet side of the circulator.

Now, if you are getting a new boiler, all bets are off. I mean, "pumping away" still applies and all, but your new boiler is one component of a system. Your piping may differ and we can take that up at that time.

realolman

Specifically,

what is the huge difference?

Pedro_3

As you described, the expansion tank is on the outlet side and it's an old style one. I bought a Smith Boiler and it came with 2 Taco 007 pumps and the installation instructions gives you a couple of ways the boiler can be installed. I only have one zone in the house and I have radiators.

Brad White_203

Air binding

loss of expansion capacity (if using older style expansion tanks), noise, annual venting rituals. Cyclical adding of fresh oxygenated feedwater, accelerating corrosion in what should be a sealed system from day-one.

Loss of capacity in upper floor radiators. Cat gets depressed and tears up your best clothes. Huge, I tell you.

For such as simple fix, so much trauma has been imposed on so many systems. On the old ones, made of sterner stuff, they did hold up well despite this. Upon replacement with modern system components and without correcting the issues, lifespans were shortened unnecessarily.

realolman

Thank you

It seems that it used to be recommended that pumps were installed on the return side.. My boiler even came that way.

I wonder why. Although it ain't much cooler, I always assumed someone thought it would be better for the pump to deal with cooler water.... (Maybe the seal on older pumps?)

Brad White_202

Exactly!

The older lubricated decoupled circulators were thought to prefer the cooler return water. (Gee, ever think of asking them??

Now we use the hottest water to lubricate most circulators, up to 245 degrees for crying out loud.

One "reason they are on the return" it is rumored, is that they fit so much more nicely into the crates, according to Dan H.

Pedro_3

Pics

I will be posting some pictures of the boiler, piping and expansion tank at my house as soon as I can get a camera so you guys can tell me what you think.

Thanks again for all your help and comments

Rebecca_4

Taco - Air Binded?

I don't think my Taco Circulating Pumps are circulating anything. I can hear something spinning but I don't think the impellers are actually doing anything. How can I check if they are "Air Bound"? What is the best way to Un-bind?

Brad White_191

You should

post this as a "New Thread" so that it gets the attention it deserves.

What is the system pressure? If the circulator is installed properly, with the shaft horizontally and the pressure is at least 12 lbs., you should not have an air problem. If the shaft is at all upward, well then...