What it is
A digital multimeter measures voltage, resistance (ohms), continuity and, on many models, capacitance and microamps. Manuals for the codes on this site call for those measurements: Trane gives an igniter resistance of 37 to 70 ohms, Goodman describes resistance and capacitance checks on capacitors and a 24 V check between R and Y, and Carrier says to check for line voltage above roughly 180 V.
How to choose
- For HVAC, look for AC and DC voltage, resistance, continuity and capacitance. Reading furnace flame current needs a microamp range (Trane lists 0.75 to 3.0 microamps; Lennox treats below 1.5 microamps as low).
- Check the CAT safety rating on the meter and use test leads in good condition.
- A non-contact voltage tester is a useful second device, not a substitute for a meter.
How it is tested
- Before each use, verify the meter on a known voltage; do not measure resistance or continuity on a live circuit (Klein's own listing warnings say the same).
- Discharge capacitors before measuring them, as Goodman's manual specifies.
Capacitors can hold a charge after the power is off. Safety terms.
Where to buy
These are Amazon links. Product page links go to one specific listing whose title we read on Amazon; we do not say it fits your model. Search links open search results, which change. Always confirm your model number and the part number in your manual.
Product pages
Searches by type or size
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Codes that mention it
Error codes whose own causes or steps name this part or check.
Bryant
Carrier
Daikin
Fujitsu
Goodman
Amana
American Standard
Bosch
Per-brand lists: Bryant AC / heat pump · Carrier AC / heat pump · Daikin AC / heat pump · Fujitsu AC / heat pump · Goodman AC / heat pump · Amana furnace · American Standard furnace · Bryant furnace · Carrier furnace · Bosch dishwasher · Goodman furnace · Lennox furnace · Rheem furnace · Trane furnace · York furnace.