I'm troubleshooting the blower not starting in a friend's HVAC system.
We think the issue is either a) a blown transformer, or b) the relay that controls the blower has blown.
The next step is to test these two components, if it's the transformer, I am wondering if there's any special information I should have beyond making sure the replacement I buy is rated for the same step-down:
Primary: 120V @ 60hz
Secondary: 24V (40VA)
Both transformers are clearly marked as Class 2 by UL.
Do HVAC vendors add any proprietary components to the transformers that would prevent me from using a non-OEM replacement? Specifically, I would be replacing an OEM York transformer with a Honeywell transformer.
Best Answer
The voltage needs to be the same, and the VA needs to be greater or equal to what you have now. If your transformer is 40VA and you replace with 60VA, that is fine.
I would stay within parts intended for use in HVAC units. Electronics supply houses will happily sell you 24VAC transformers, but they may not be listed (certified) for HVAC use. Anyway, HVAC units will be cheaper due to being made by the millions.