Keep on Pumping: Tips for maintaining a heat pump

Heat pumps are becoming common­place in the city as New Yorkers replace fossil fuel-powered boilers with heating and cooling systems that run on electricity. 

Buildings that have gone fully elec­tric are already reporting signif­i­cant reduc­tions in their carbon emis­sions and energy bills. Others are drawn to heat pumps for the greater comfort and room-by-room temper­a­ture control that older boiler systems often cannot match.

The city govern­ment is also making heat pumps a key part of its building decar­boniza­tion strategy, with plans to install window heat pump units in 20,000 New York City Housing Authority apart­ments over the next five years.

While tech­no­log­ical advances and a growing market have made heat pumps much more common in recent years, most New Yorkers are less familiar with what needs to be done to keep these heat pumps running in top form over many years. 

“These systems behave differ­ently than what a boiler-based building would behave. They depend more on control, airflow, elec­trical systems, so even a small issue can affect comfort or lead to higher energy bills,” said Joseph Novella, Chief Building Scientist at Nova 1, a mechan­ical contracting company that special­izes in elec­tri­fying New York City buildings. 

But when designed and commis­sioned prop­erly, he added, ​“these systems are better, low main­te­nance, faster, comfort­able, and overall better for the grid and the environment.” 

It Starts with the Install 

The most impor­tant heat pump main­te­nance issue to consider is right at the begin­ning — choosing the right installer, one who is trained, knowl­edge­able, and well supported. 

“Whoever is managing the elec­tri­fi­ca­tion process has to make sure that the consul­tants and contrac­tors involved are prop­erly trained, certi­fied, and working closely with the manu­fac­turer of the equip­ment,” Novella said. He noted that when­ever his team is called in to trou­bleshoot prob­lems with the equip­ment, the issues often stem from poorly designed systems or incor­rect instal­la­tions completed by contrac­tors with limited expe­ri­ence or from poorly designed systems.

Don’t Ignore The Basics

Once heat pumps are prop­erly installed and set up, they are expected to require very little main­te­nance because they operate as sealed systems. Unlike fossil fuel – based burners, heat pumps do not rely on combus­tion, so much of the main­te­nance asso­ci­ated with combus­tion systems disap­pears. There is no burner to tune up and no need for fresh air intake into a combus­tion chamber.

One of the main main­te­nance tasks for heat pumps is replacing or cleaning the filters in the air handlers. The outdoor unit also typi­cally contains a heat exchanger or coil that needs peri­odic cleaning. 

“Just like a window air condi­tioner, the heat pump system has a little filter over the coil. Because so much air is being pulled through that coil, dust can accu­mu­late there and inhibit heat transfer, making the system less effi­cient,” said Paul Reale, director of training at the CUNY Building Performance Lab.

Cleaning the filters is pretty straight­for­ward. ​“The filters are right in the air handler. So in a wall-mounted air handler, you basi­cally just open the cover, pull the filter out, rinse it off, and put it back,” Novella added.

Signs For Servicing

The clearest sign that a heat pump system is malfunc­tioning is when an apart­ment is not being prop­erly heated or cooled. Often, this can indi­cate some­thing as simple as dirty filters. 

“I’ve had calls where people complain that their (heating) system is not working — turns out that it is working, but the filters weren’t clean,” Novellas said.

Another impor­tant signal comes when the system using too much elec­tricity. When resi­dents complain about unusu­ally high elec­tric bills, tech­ni­cians find that the system’s elec­tric resis­tance backup heat has been turning on too often. Heat pumps move heat from one space to another rather than generate it, making them highly effi­cient. But elec­tric resis­tance backup systems create heat directly from elec­tricity, which makes them far less effi­cient and more expen­sive to operate. If your elec­tricity bill spikes, call a heat pump tech­ni­cian who will be able to prop­erly diag­nose the problem. 

Another serious issue to be on guard for is a refrig­erant leak. These leaks occur within refrig­erant pipes and are primarily caused by improper instal­la­tions or aging systems. Indications for refrig­erant leaks include ice buildups in pipes or oil stains near joints and occa­sion­ally, a contin­uous hissing or bubbling sound can also signal a weak joint and leaks. This fix should also be left to a tech­ni­cian, who will need to test and monitor pres­sure levels.

“When tech­ni­cians realize the pres­sure is low, they’ll just go ahead and pump more refrig­erant. Best case scenario is that the tech­ni­cian coming to refill your refrig­erant will also find the leak and fix it,” Reale said. 

Leaks are impor­tant to address imme­di­ately because of the envi­ron­mental harm they can cause. Most refrig­er­ants are made of extremely powerful green­house gases that trap heat when emitted into the atmos­phere. So once the refrig­erant leaks, the direct emis­sions can cancel out the emis­sions saved by using a heat pump in the first place.

Most heat pumps have tradi­tion­ally used a refrig­erant called R‑410A, which has an extremely high global warming poten­tial — about 2088 times that of carbon dioxide over the course of 100 years. But this is being phased out in favor of newer refrig­er­ants such as R32, with much less warming poten­tial. However, R‑410A usage is still allowed in repairs, so users should be aware of what type of refrig­erant their system uses. 

Best Practices

Good instal­la­tions should include training for building super­in­ten­dents and even occu­pants. Installers may offer educa­tional get-togethers for resi­dents, explaining controllers, the different modes of the equip­ment, and how to change filters. These events should also include simple, but not always obvious, best prac­tices. For example, users should not turn off their systems even if they’re away for days at a time; these machines are designed to run all the time. It is best to use a modest temper­a­ture setback instead of shut­ting off the whole system.

The experts also recom­mend that build­ings adopt a prac­tice of always servicing all equip­ment once a year. If servicing is needed more frequently than that, building managers should consult the service tech­ni­cian, as it could be a sign of larger problems.

In general, resi­dents or building owners can extend the life of the heat pump through simple measures. 

“Keep it clean. Change the filters. Keep an eye on the perfor­mance. Call in the tech­ni­cian. Have it regu­larly serviced,” Reale said. Typical heat pumps last for 10 to 15 years. With good servicing, its lifespan can reach up to 20 years.“It’s impor­tant that you don’t just set it and forget it. Keep an eye on these systems,” he added.