Can I replace a Bell Gossett 103252 pump with a 103251?

if pump it self is good look for a replacement motor can do search online or search for companies such as grainger --pump supply --plumbing supply companies online such as national https://www.nationalpumpsupply.com/?gclid=EAIaIQobChMImanlsNGl9gIVCgmGCh0vjg_xEAAYASAAEgIaiPD_BwE also check coupler ---this way for now dont have to drain system the companies should be able to cross reference a motor

The motor bearing must be defective.

the pump itself doesn't make any hot water it merely circulates it around your house to the sink outlets , this pump has a unique feature as it auto senses the temp of water and starts itself when it dips low , if you don't get any hot water even if you wait 4 it a moment then id have a service tech ck your water heating equipment , as it seems its not working

Sounds like it is not getting oil. The bearing oil fill cover can be removed by lifting outer plate with a screwdriver. Ck that the wicks are covered with oil , if not oil them. Put 3 drops in motor oil fill tubes. If still squealing, replace.

It sounds like the pump is not operating properly. I would guess convection is causing some of the rooms to heat or you have another pump. Check if you have power at the pump, if so it is bad. If not then check the thermostat and relay, one of those probably failed.

Replace the bearings...they are the noisy part

how is the pump wired up temp or run

The following websites are parts suppliers for Bell and Gossett pumps and should be able to tell you the exact instructions especially if you buy the impeller from them:

www.statesupply.com/pumps-for-heating/bell-and-gossett/series-pl-pumps-and-...

www.nationalpumpandsupply.com/bell-gossett-pl-pump-pl-55-2-5-hp-motor-1bl03

If the pumps run, but do not circulate water

make certain that all the air is out of the system

bleed air from coin vents and open caps on auto vents

If there are not sufficent means of air elimination, there are some other options, such as using an auxillary pump to force the air out

you should call and contact Bell & Gossett .(847)966-3700 Address: 8200 N. Austin Av. Morton Grove,IL 60053. Ask them that if the part no # 103400 Price $260 fits for your pump Good luck.