In alt.home.repair, on Mon, 11 Dec 2017 02:43:28 -0800 (PST), trader_4
wrote:
On Sunday, December 10, 2017 at 7:27:50 PM UTC-5, micky wrote:
My neighbor, who is quite a jerk**, is having trouble with his Carrier
oil furnace. He says the furnace goes on and off but the fan stays on
all the time. He says the thermostat is in the auto position, not On.
Looking at the wiring diagram, it seems clear to me that the fan is
controlled by the G and Y terminals on the control box, which is
controlled by the G and Y terminals on the thermostat. Which are
probably connected by green and yellow wires. And maybe (unlikely) the
thermostat is bad, or stray wires from the G or Y are touching the other
terminal. And at the very least disconnecting one of those two wires
will stop the fan or not, and give essential debugging information .
(And reconnnecting it right after, because the fan is needed when the
burner is burning. I'm talking about the warm air house circulation
fan, not the fan that blows air into the oil burner.)
Also, and this I'm less sure of, the fan can stay on for months without
stopping and without burning out without shortening its life much. So
being on 24/day for a few days didn't hurt the fan, but might have cost
him a little money.
I don't need any help on this afaik,since I've spent plenty of time on
an identical furnace.... unless I said something incorrect above. Did
I?
**If I hadnt' had bad experiences with him, I'd print out the wiring
diagrams of the furnace etc. and take it with me tomorrow evening, but
he's been such a pain.
How bizarre. The guy is an AH, you're going to go over there anyway,
Curiosity has me.
but because he's an AH you're not going to take wiring diagrams with you?
I wasn't, but my memory for stuff like that is bad, and the page was
right in front of me, so I printed it.
He never identifies himself when he calls. Last
winter when I went over and couldn't fix it, I asked him when he got it
fixed to find out what the problem was and let me know. He didn't do
that. I asked him to call me when the paid repairman is there. He
didn't do that.
But the prize was when he wanted an oil pump, and I have spare parts for
many things because when a neighbor got a new furnace, I got the old
burner. So it was the day of the funeral of one of my best friends (and
he knew that), my first good friend to die, under depressing
circumstances, and after I got home from the funeral, instead of going
to sleep like I wanted to, I took the time to take the oil pump out of
the burner, clean up the dripping oil, wrap it up and put it on the
porch, as I told him the night before I would do. He never came to
pick it up, he never called to tell me I could put it back in the house,
he never called at all, and he never thanked me. Nothin'.
Since then I've brushed him off a couple times, and I wouldn't even go
tomorrow except I'm curious and he lives less than 100 yards away.
I'm especially curious because he told me that pros told him the control
box needed replacing. (He called me 3 or 4 days ago to get my spare
control box but a) I used it already, b) he told me the problem and I
told him the control box has nothing to do with it.) He gave me the
name of the company that told him that and their webpage says they've
been in business since 1983. That's a long time to not understand what
controls the fan. His business address seems to be his home, and he
has a biggg home, 2 2/2's or 3 1/2 high, with a biggg swimming pool, and
a tennis court, a 3-acre lot backed by acres of woods, neatly trimmed
bushes and neatly mown lawn, in an expensive suburban n'hood not so far
away. He couldn't screw up that often, so this must be some shlock
employee giving out bad advice.
I see nothing but trouble here. I'd just stay away. The blower could
very well be stuck on because of a bad controller, which was what was
diagnosed.
There is no controller, only a relay. Disconnecting the relay coil
would be the next step. Its the black and blue wires, connected to the
G and C terminals respectively.
No, he was told the problem was what he called when he talked to me "the
grey box" (which I then called the control box). Or at least that's
what he wanted to get from me. I once found my exact box on the web and
I think it was under 100, but a furnace repair company would probably
charge 200 or more. If they had actually told him it was the relay, $45
plus 50 labor, I think he would have done it. It's the 2 hundred
dollars plus what, 50 - 200 labor** that's making him balk. If I
remember, I'll ask him how much they wanted.
The relay otoh would cost $20 as a relay and maybe 45 as a furnace part
and I think the fan relay enclosure is right on the face of the furnace,
chest high and easy to get to, but I don't have the exact part and I'm
not going to do it.
I know for sure he said they said it was the control box, and I know for
sure, that's not the problem.
**I wish there was a webpage that rated furnace repairs, like there is
for auto repairs.
Or like Gfre said,
very old furnaces just used thermostatic switches in the furnace plenum
to turn the blower on and off.
Not in the plenum, in the thermostat.