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am (Laurie Forbes) wrote in message ...
This group is knowledgeable about so many topics I though I'd ask
about a problem I'm having with a Trane high efficiency (condensing,
model TUX080) furnace installed in my house. Every once in a while,
the furnace gets stuck in the cool-down part of the heat cycle wherein
the flame is out and the blower keeps running until the microprocessor
is manually reset by turning the power off/on. This is particularly
annoying when it happens in the middle of a cold night as it's usually
discovered because the house gets cold and one has to get up to reset
it. The processor is flashing an error message but, with the help of
the dealer, I've checked out the suggested fault possibilities to no
avail (ignitor, voltage level or grounding problem).

Anyhow, the dealer also mentioned that line voltage noise and spikes
can also glitch the processor so I am thinking of installing a surge
suppressor in the line input. One way would be to use a suppressor
typically used for electronic equipment such as computers but they are
plug in rather than permanent wired. Any comments on using such a
device (by installling a plug in the furnace line and plugging it into
the suppressor) would be appreciated, or, any other suggestions.

Another possibility I don't want to think about is an intermittant
processor board problem (a replacement board is nearly $500 CAN with
no assurance that it will correct the problem).

TIA for any help............

Laurie Forbes

You can get EMI suppressor or filter modules on the surplus market,
they're rated by amperage or wattage. I used to get them from the
local electronic surplus dealer, they've folded up shop, though. The
one I have is in a flat, square tin can, two isolated teminals in, two
out, can is the common ground. Ran about $6 and was easy to get wired
up in line with the mini-lathe motor controller. Hash from that was
driving my computer UPS nuts.

In Canada, I have no idea who would be a supplier. In the US,
Digi-Key and Mouser would be starting places for new ones, Gateway
Electronics and All Electronics are two web suppliers that might have
them periodically as surplus. Some types are from PC power supplies
and have the common appliance cord receptacle, others are strictly a
permanent wire-in solution. These eliminate EMI from other sources
but don't deal with dips in line voltage or brown-out conditions. For
those conditions, a ferro-resonant transformer would be needed, Sola
is one brand that shows up on the surplus market.

Having had to replace a controller board on my furnace, I can
emphathize. Lots of money for not a whole lot of technology on it.

Stan