Checking a Heat Pump in Heat Mode - Short #178
11/07/23 • 14 min
In this short podcast, Bryan talks about checking the charge of a heat pump in heat mode. This skill will become more critical as ambient temperatures get cooler.
The most reliable way to check and set the charge regardless of operating mode and season is to weigh the charge. This method is most practical during installation and commissioning, and proper commissioning can prevent issues with charge levels later. Weighing the charge is recommended for big repairs, like major component replacements.
But in many cases, we don't need to check the charge by hooking up gauges; we can check for proper operation by taking a few line temperature readings. Before carrying out any tests or taking readings, make sure the heat pump is defrosted and that you've carried out a full visual inspection. You can carry out a full delivered capacity test in either cooling or heating mode (without the electric heat strips energized) to determine how many BTUs the system is moving. Some simpler tests will require you to compare the discharge vapor line and suction line temperatures to the outdoor temperature and the liquid line temperature to the indoor temperature.
Manufacturers will give specific instructions for their units, including covering the condenser, and they may have charts to help you calculate system pressures based on indoor and outdoor temperatures. If you want to check suction pressure on the low side, you'll always use the common suction port, but you can take either discharge pressure or liquid pressure on the high side.
Bryan also covers:
- Critical charge
- Ductless system charging practices
- Some manufacturer-specific practices
- Indoor temperatures and system pressures
- R-22 rules of thumb
- Total discharge superheat
- Staging and capacity considerations
- Weighing out when in doubt
Read the tech tip about this topic at https://hvacrschool.com/checking-charge-heat-pump-winter/.
Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.
If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.
Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.
Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).
In this short podcast, Bryan talks about checking the charge of a heat pump in heat mode. This skill will become more critical as ambient temperatures get cooler.
The most reliable way to check and set the charge regardless of operating mode and season is to weigh the charge. This method is most practical during installation and commissioning, and proper commissioning can prevent issues with charge levels later. Weighing the charge is recommended for big repairs, like major component replacements.
But in many cases, we don't need to check the charge by hooking up gauges; we can check for proper operation by taking a few line temperature readings. Before carrying out any tests or taking readings, make sure the heat pump is defrosted and that you've carried out a full visual inspection. You can carry out a full delivered capacity test in either cooling or heating mode (without the electric heat strips energized) to determine how many BTUs the system is moving. Some simpler tests will require you to compare the discharge vapor line and suction line temperatures to the outdoor temperature and the liquid line temperature to the indoor temperature.
Manufacturers will give specific instructions for their units, including covering the condenser, and they may have charts to help you calculate system pressures based on indoor and outdoor temperatures. If you want to check suction pressure on the low side, you'll always use the common suction port, but you can take either discharge pressure or liquid pressure on the high side.
Bryan also covers:
- Critical charge
- Ductless system charging practices
- Some manufacturer-specific practices
- Indoor temperatures and system pressures
- R-22 rules of thumb
- Total discharge superheat
- Staging and capacity considerations
- Weighing out when in doubt
Read the tech tip about this topic at https://hvacrschool.com/checking-charge-heat-pump-winter/.
Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.
If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.
Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.
Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).
Previous Episode
An IAQ & Dehum Case Study w/ Genry & Nikki
Nikki Krueger and Genry Garcia return to the podcast to talk about a recent IAQ & dehumidification case study on a vintage home in Miami. The home was very clean but had a musty odor and VOC concerns. You can read the case study in the “Literature” section at https://www.santa-fe-products.com/about-us/media-resources/ or https://hvacrschool.com/case-study.
Blower door tests and ZPD revealed that the home was leaky, and the crawlspace was also not properly encapsulated. The options were to tighten the building and/or mitigate the problem by improving the HVAC system. The homeowners chose to improve the HVAC, which Genry did by installing a ventilating dehumidifier (Santa Fe Ultra98H), reducing system tonnage (3.5 to 2 tons), and putting in new ductwork.
One of Genry’s key tips to address intermittent moisture issues is to pay attention to fluctuating pressures, not just under the blower door test conditions. Ongoing monitoring is crucial in these studies to measure the home under several different typical conditions. He also relies on blower door tests to determine if encapsulation is necessary or needs improvement, as insulation and encapsulation can bring new issues in their wake.
Extensive testing and working with other contractors (such as home insulators) are the best ways to get a solution that makes the homeowner happy. We need a holistic approach to design to achieve a homeowner’s IAQ and comfort goals, not necessarily following strict design guidelines to a T.
Nikki, Genry, and Bryan also discuss:
- Zonal pressure diagnostics (ZPD)
- Dehumidifier ductwork
- Dehumidifier selection
- Attic encapsulation, condensation, and duct leakage
- MAD AIR
- The importance of IAQ case studies and the insights we can get from them
- Effects of insulation
- Dehumidifier performance in part-load conditions
- Mechanical equipment design
- Consulting the ACCA design manuals
- Maintaining equipment and sustaining positive results
Stay tuned for the companion tech tip.
Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.
If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.
Check out our handy calculators HERE.
Next Episode
Why and How of Combustion Analysis w/ Tyler Nelson
Bryan Orr interviews Tyler Nelson, an HVAC expert with over 20 years of experience as a contractor. They have an in-depth discussion about combustion analysis and why it is becoming increasingly important for HVAC technicians to utilize this process.
The conversation provides an overview of combustion analysis benefits and why HVAC pros should incorporate it into their standard operating procedures. Tyler offers insightful perspectives from his decades of contracting experience, including his knowledge of how field conditions vary and factory settings may not translate perfectly.
Carbon monoxide poses several dangers to customers and HVAC technicians. Tyler talks about CO poisoning risks and how analyzers can help detect issues. He also covers AHRI Guideline X for cracked heat exchanger testing and emphasizes the need to use combustion analyzers, not just visual inspection, to reliably detect cracks.
Tyler also demonstrates the use of the Sauermann combustion analyzer and mobile app. He highlights key features like replaceable sensors, app control and reporting, and programming for optimum CO sensor protection. He details how combustion analysis allows you to optimize setup, monitor equipment health, and troubleshoot issues.
Tyler and Bryan also discuss:
- Why combustion analysis is critical for proper HVAC system installation, maintenance, and diagnostics
- CO poisoning and risks to HVAC technicians
- AHRI Guideline X
- The role of combustion analysis in system commissioning, maintenance, and diagnostics
- Sauermann combustion analyzer and mobile app
- Advice for technicians to embrace innovations like analyzers while retaining old-school skills and knowledge
Read AHRI Guideline X in its entirety at https://www.ahrinet.org/search-standards/ahri-guideline-x-induced-draft-furnace-heat-exchanger-inspection.
Learn more about Sauermann tools at https://sauermanngroup.com/en-INT, and you can connect with Tyler on LinkedIn HERE.
Learn more about the 5th Annual HVACR Training Symposium at https://hvacrschool.com/Symposium24.
If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.”
Subscribe to our YouTube channel at https://www.youtube.com/@HVACS.
“Check out our handy calculators HERE or on the HVAC School Mobile App (Google Play Store or App Store).
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