In-Line Heating Pump Troubleshooting

Heating pump maintenance isn’t something that needs to be completed often. So when it comes time to perform maintenance on your pumps, it can feel more unfamiliar than working on a flushometer or other facility fixtures that require more frequent repairs. Reading this heating pump troubleshooting article will help you identify the problems with your pump, and know what needs to be done to repair it. 

This article shares the top 4 items that break in a popular 3-piece, in-line heating pump (note that although it is considered a 3-piece pump, it actually has 5 major parts). It includes what signs to look for, along with what your next steps should be. Also included in the article are pump oiling instructions, and additional tips to help you increase the longevity of your pump, and deter you from making common pump maintenance mistakes. 

The pump featured in this article is the Bell & Gossett 100 Series Single Phase Circulating Pump (B & G model number 106189). We chose to highlight this pump because it’s a popular pump found in a variety of settings. Note: These maintenance tips can be applied to other similar heating pumps too, but just keep in mind that these tips might not match up exactly if you are working on a different pump.


B&G Series 100 Pump Part Identification

The 5 major parts of the Bell & Gossett Series 100 Circulating Pump are the motor, coupler, bearing assembly, impeller, and the pump body. The motor sits in the ring motor mount set. The bearing assembly includes all of the following parts: bearing bracket, shaft & sleeve, impeller key, front bearing gasket, front bearing, seal kit, body gasket, and impeller nut. The pump body is also called the volute. The above image points out the seal kit, located in the seal assembly, because (spoiler alert) it’s usually the first part in the pump that needs to be replaced (more on that below). Also noted in the image are the points in the pump that need to be oiled (details on oiling can be found towards the bottom of the article). 


Bell and Gossett Circulating Pump Troubleshooting

Here are are problems, causes, and solutions for in-line pumps. They are listed in order from most common to least common. 

  1. PROBLEM: The pump is leaking where the bearing assembly meets the pump body. 
    CAUSE: The seal kit is breaking/broken or the bearing assembly is breaking/broken.
    SOLUTION: For most in-line pumps, including series 100 Bell and Gossett pumps, the seal kit is located in the bearing assembly. When that is the case and this problem is occurring, it is recommended you replace the entire bearing assembly. This goes for whether the seal kit is broken, or if the bearing assembly is broken. This is because there is less room for error when replacing the bearing assembly than there is when you install the seal kit only. It’s also worth noting that the bearing assembly is under warranty for at least a year, whereas the seal kit isn’t, since manufacturers have to account for potential user error during installation. It is also a much easier installation to make. Find the bearing assembly in our Bell & Gossett Pumps page.
  2. PROBLEM: The pump shaft is not turning, but the motor shaft is.
    CAUSE: The coupler is broken, or is going to break soon. There are two types of couplers your pump can use: a spring coupler, or a 3-piece coupler (also known as a Woods coupler, which is the manufacturer of this coupler style). For 3-piece couplers, you’ll know they are breaking when you see little shavings on the floor underneath the location of the coupler. For spring style couplers, which are used for booster pumps like this one, you will hear thuds or bumps, which will signify that the coupler needs to be replaced. The coupler is designed to fail before other pieces. It most often occurs when a pump is misaligned. Over-oiling the motor can also cause the coupler to break. Read our oiling tips below to ensure you do not over-oil your heating pump. 
    SOLUTION: Replace the coupler. Keep in mind when replacing a spring style coupler, it needs a little bit of space to account for expansion during heating. When hooking the coupler pieces together, leave a quarter inch of space for the coupler to grow. Find the coupler replacement you need in our online selection of Bell & Gossett couplers. If you don’t see the coupler you need, call to place your order.
    *Watch our Troubleshooting your Bell and Gossett Series 100 Pump Video for more information about coupler replacement and ring mounts. 
  3. PROBLEM: The motor is not running. 
    CAUSE: The motor was not being oiled/maintained, something dripped on the motor, or the wrong oil was used for the motor. If you over-oil, the oil gets into the motor mount, making it soft, which can then cause the unit to sag and cause the coupler to go as well. Over oiling can also cause oil to get on the motor windings, which causes them to act as a dust magnet, thus causing the motor to overheat and eventually fail.
    SOLUTION: Replace the motor. Find the replacement motor in our Bell & Gossett Pumps page.

To find additional Bell & Gossett pump parts, including an impeller, motor mount set, pump seal kit, and pump body gaskets, view the Miscellaneous Bell & Gossett pump parts page. 


Bell and Gossett Series 100 Oiling Instructions

Bell and Gossett Series 100 Oiling Instructions

When installing a new pump, it is important that you oil it. Your pump will come with a tube of oil labeled with numbers that describe how much oil to add to the 3 oiled locations. 1 goes into the oil well. 2 and 3 ( the lesser amounts) go to the other two oil ports. Besides the initial installment, oiling the pumps is done on-demand, and very minimally. Your pumps should be inspected at a minimum of every 6 months. If you notice the pump squeaking, then more oil needs to be added. When a motor is making squeaking sounds, then, and only then, should you add a couple of drops (2-3) of oil into the motor well.


Equiparts is a distributor of all major heating pump manufacturers, including Bell & Gossett, Armstrong, Taco and Hoffman. We carry all of their pumps and the repair parts needed to maintain them. Call for additional help, or to place your order.

Toll-Free: 800-442-6622
Pittsburgh: 412-781-9100

Phone hours: Monday-Friday 8:00 AM – 4:00 PM EST

6 Commercial HVAC Maintenance Tips

Maintaining the HVAC system in your commercial facility is a sizable ongoing task. Review our HVAC maintenance tips below to break down what tasks need to be completed, and how often they should be reviewed. We recommend creating a schedule so routine maintenance like replacing filters, removing debris, and maintaining condensate pans are checked regularly throughout the year. The key to maintaining your commercial HVAC systems is routine maintenance, as well as using the right commercial maintenance gear and cleaning chemicals needed for the job. 


1. Check & Replace Filters

Check and replace your air filters on a routine basis. Clogged filters are the primary cause of HVAC system failures. You can prevent this by checking your HVAC system’s filters every 1 to 3 months, depending on the condition/type of facility you maintain. Dirty, clogged filters cause a mirage of problems:

  • Clogged filters can result in more stress on the blower fan, causing it to have to work harder to push air. This leads to higher energy bills and a decrease in the life span of your HVAC system. 
  • Dirty filters allow pollutants to travel through the air. This can adversely affect employees and/or patrons with allergies. The dirt and dust that pass through will also find its way onto surfaces in your facility, creating the need for more frequent surface cleaning. 
  • Clogged filters can also cause systems to overheat or freeze up if air from the furnace, heat pump, or air conditioner cannot travel out of the system. 

2. Keep Evaporator Coils Clean

Keep the evaporator coils on your units clean to prevent build up. Evaporator coils help draw the heat out of air before it circulates into the facility. Mold and dirt can build-up on the coils and cause them to become clogged or frozen, especially during the peak of the summer heat. Keeping evaporator coils clean from mold and dirt build-up will extend the life of the unit, and prevent major repairs in the future. 

Recommended product:
Use a professional grade coil cleaner to clean your evaporator coils. Zenacoil 18 oz Aerosol Coil Cleaner (Part #79470) has a no-rinse formula, which makes for easy cleaning.


3. Remove Debris

Remove the debris from your outdoor HVAC units to protect your units from damage. Dirt, leaves, twigs, and garbage can create blockages and attract more build up if not removed. This is especially true for HVAC units located on large, flat roofs or near trees and other vegetation. Outdoor units must be routinely checked, with a most vigilant eye in the late Summer and early Fall months when the seasons change and trees lose their leaves. Build up causes a restriction in air flow. The lower the air flow, the harder your unit has to work. You can turn off the unit to clear the unit of debris, then clean it with a hose to wash away any debris around the unit. The coil cleaner listed above can be used to remove dirt that is clinging to the unit.


4. Clean & Straighten Fins

Clean and straighten fins on your outdoor HVAC units to enable proper airflow. Fins provide airflow to the unit and help direct heat away as well. These can get clogged and bent over time and this will constrict air flow to the system, causing it to work harder. 

Recommended product:
Our Multi-Fin Tool Kit (Part #34815) to help clean and straighten fins. The interchangeable heads are designed to fit units with fin spacing of 4–24 fins per inch. It is important to use the proper tool to straighten HVAC fins because they are sharp and easy to bend. 


5. Use Condensate Tablets and Treatments

Using condensate tablets or treatments help maintain condensate drain pans. Untreated condensate water quickly becomes covered in algae, which in turn can create unwanted odors and overflow/water damage because of clogged drain lines.

Recommended Products:
Pro-treat Condensation Economy Drain Pan Treatment Tablets (Part #79802) 200 count
Flow-Plus Condensate Pan Treatment Mini Tablets (Part #79805) 25 count
Flow-Plus Condensate Pan Treatment (Part #79804) 10-ounce tub


6. Schedule Routine Maintenance

Scheduled routine maintenance is vital to ensuring HVAC systems continue to operate in their highest capacities. Some areas that can be focused on are: 

  • Monitoring the system controls to ensure they are working properly, and recalibrating them as needed.
  • Checking the air ducts to make sure there is not any hazardous build up occurring over time. 
  • Reviewing all moving parts within the HVAC system, and completing preventative maintenance to increase longevity of building systems.

Related HVAC Maintenance Products

Condensate Big Shot Drain Gun (Part #39132)
This SWOOSH® Drain Gun by Diversitech blows out drain lines instantly. It features a new, larger 20-gram SWOOSH CO2 cartridge that delivers 800 PSI of oil free air to clear the line, with 25% more capacity. Each unit comes equipped with a tapered fitting to work on 3/8 inch – 3/4 inch drain openings. The flexible hose assembly maneuvers through cabinets, coils, and hard to reach drains. This drain gun helps to reduce labor costs and time on service calls. 

Drain Gun CO² Cartridges (Part #39172) 12 Pack


For HVAC repair parts or questions, call and speak to one of our repair parts specialists. 800-442-6622 M-F 8:00AM – 4:00PM EST. We are happy to assist you!

Understanding Thermostatic Mixing Valves

Thermostatic mixing valves are used throughout most facilities. They can be found where there are faucets, showers, and other point-of-use locations where people come into contact with water at your facility. Why are thermostatic mixing valves present in areas where water comes into contact with people? For one very important reason: to protect your patrons from scalding water. 

In this article, you will learn exactly how thermostatic mixing valves work, why they are needed, where they are installed, when they need to be replaced, and more in a Q&A format. After the Q&A’s, you can learn more about the valves we carry and the most popular heating equipment manufacturers we work with.


Thermostatic Mixing Valve Q&A

Q: What does a Thermostatic Mixing Valve do?
A: A thermostatic mixing valve blends hot and cold water to ensure safe temperature water at the outlet. 

Q: Why do we need Thermostatic Mixing Valves?
A: Thermostatic mixing valves are used to accurately mix hot and cold water before it comes into contact with people. This stops scalding water from coming out of the shower or faucet, which can be dangerous.

Q: Where are thermostatic mixing valves used?
A: In commercial facilities, you are likely to find two different types of thermostatic mixing valves:

  1. 1. Point-of-Use Valves: Also called Single Thermostatic Mixing Valves. These can be found at the faucet or showerhead.
  2. 2. Group Control or Master Thermostatic Mixing Valves. These valves control a group of point-of-use fixtures, like a shower room with 10 showerheads. 

Q: When does a thermostatic mixing valve need to be replaced?
A: You will know that a thermostatic mixing valve is going bad when the water temperate from the point-of-use starts to fluctuate. A proper functioning mixing valve will maintain a constant temperature.

Q: What is the difference between a tempering valve and a thermostatic mixing valve?
A: They are very similar but essentially, a thermostatic mixing valve is exact, and a tempering valve only tempers the water, so with it, you will get fluctuation. It is acceptable to use a tempering valve in areas where direct contact with skin will not occur, like for water used in laundry machines, where fluctuation is alright.

Q: When do you need to pair a temperature gauge with a thermostatic mixing valve?
A: A temperature gauge is only required with a mixing valve when it is being used in conjunction with eye safety fixtures.

Q: Why are thermostatic mixing valves the preferred water temperature controlling devices for large commercial facilities?
A: Thermostatic mixing valves are the preferred water temperature controlling devices in commercial buildings like health care facilities because they limit maximum outlet temperature even when the pressure or flow differs due to the outlet’s location or distance from the water source.


Thermostatic Mixing Valve Manufacturers

We carry thermostatic mixing valves, as well as a wide variety of other heating equipment, from Powers, Symmons, Lawler, Leonard, Bradley, Acorn, and other heating equipment manufacturers.

Thermostatic Mixing Valve Manufacturers

Give us a call today to get help finding the repair parts and fixtures needed to keep your facility running smoothly and your water safe for your patrons.

You can view a sampling of the thermostatic mixing valves we carry on our website in the Thermostatic Mixing Valves section. However, know that this is only a small sampling of the thermostatic mixing valves we carry.

Give us a call to order the thermostatic mixing valves needed for your facility. If possible, note the manufacturer and manufacturer model number of the valve or the Equiparts part number. If you don’t know either of these numbers, then give us a call and one of our product experts with help you find the mixing valves needed for your facility.

Toll-Free: 800-442-6622 // Pittsburgh: 412-781-9100