uskv wrote:
My AC' Fuse keep blowing every 2-3 days.

AC is 4 years old. Already replaced 3 fuses. AC has disconnect with
set of two fuses (35A 250V) in the box on the wall outside, by the
AC.

Thermostat's working fine. Checked contactor ( or relay??) - it does
show 24V.

After replacing fuse AC does run for several hours.

What is causing AC to draw more current ? Motor ? Capacitor next to
contactor ( or relay ??) or Contactor it self ?

Any help/suggestion is appreciated.

Thanks,


It may NOT be drawing too much current.....

Before you call a AC tech......

When the fuse(s) "blow", are both their end caps still shiny
copper/brass colored or is one cap darkened?

If it's the later, you may just need to clean the fuse clips and squeeze
them down a bit so they make better contact with the replacement fuse.
You should also look at the disconnect's switch blades to see if they
look darkened by heat.

I say this because I've been plagued over the years by a more than one
fused disconnects which after they'd been in service about ten years
began to "blow" fuses because current flowing through the less than
perfect contact resistance in the clips and/or switch blades raised
local temperatures enough enough to heat the fuse end caps and melt the
solder connecting that cap to the fuse link inside.

The heat darkened the end caps as though they'd been in a fire and the
fibre bodies of the fuses were also charred and brittle next to the end
cap. The fuses didn't really "blow", they just developed open
connections inside when the solder melted.

HTH

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.