Troubleshooting a heat pump
The heat pump is on. The house isn't warming.
A heat pump's air feels cooler than a furnace's, even when it's working. If it's truly not heating, these are the usual reasons.
Before you call anyone
Not warming: check, understand, then stop
Work down in order. Blue is safe for you to check; red is where you call.
Safe to check yourself
Check these first
From Trane's advice to owners.
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Source: Trane, Troubleshooting Tips for a Heat Pump Not Heating, checked 2026-10-22.
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Source: Trane, Troubleshooting Tips for a Heat Pump Not Heating, checked 2026-10-22.
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Source: Trane, Troubleshooting Tips for a Heat Pump Not Heating, checked 2026-10-22.
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Source: Trane, Troubleshooting Tips for a Heat Pump Not Heating, checked 2026-10-22.
Worth a visit from us
What it usually means
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The reversing valve
If it cooled fine in summer but won't heat now, the valve that switches it from cooling to heating may be stuck or failed.
What we do: We test the valve and its control before anything is replaced.
Source: Trane, Troubleshooting Tips for a Heat Pump Not Heating, checked 2026-10-22.
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A refrigerant leak
A heat pump only runs low on refrigerant if it leaks.
What we do: We find and fix the leak before we recharge.
Source: Trane, Troubleshooting Tips for a Heat Pump Not Heating, checked 2026-10-22.
Stop, and call
When to stop and call
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Hissing, pooling liquid or a frozen coil
Those are signs of a refrigerant leak. Trane's advice is to call for service right away.
Source: Trane, Troubleshooting Tips for a Heat Pump Not Heating, checked 2026-10-22.
Tell us what it's doing. We'll take it from there.
Call and describe the problem: the noise, the smell, the room that never warms up. Or book a visit online.
