Okay here's the low down . . .
Pilot light sayed lit all summer. First cool day we fired her up and all was
good . . . or so we thought. Pilot light out . After several relights we
called a tech out. he changed the thermocoupler(sp?) and tried it. seemed
okay.I asked him to cycle it a few times because we found that it was going
out when the burner shuts down. So after a few more tries, the pilot goes
out again. He then trries to clean out the pilot line. Same result. After
checking the burner he concludes, "it must be the gas valve". Installs -
checks - gets $400.00 all told - leaves - all good. . . get home from work
this morning and the house is at 60F. I have a call out for him to come
back, however in the mean time I have a few Questions.
Is it normal to not use any meters or other equipment to test valves or
thermocouplers? He said there is no way to test them.
Have you ever seen this before?
What else could the problem be?
Doesn't this mean the gas valve was NOT faulty and I should get (at least)
the cost of the part back?
The specs on my boiler are as follows:
Viessmann Atola Model GLN-25
Installed in 1983
A thermocouple generate about 300 millivolts (0.3 volts) of DC current. You
can test them with a good multimeter. They're inexpensive and can go bad
overnight. A new one every three or four years is not a bad idea.
Pilot burner and/or pilot orafice. If there is insufficient gas going to
the pilot burner, the vacuum (draft) created when the main burners shut down
could suck-out the pilot. If this has never happened before, you'll
probably be OK with replacing the pilot burner assembly, which includes the
orafice. I have taken them apart and reamed out the orafice with a piece of
22 or 24-guage copper wire. This reults in a pilot orafice hole much larger
than it's supposed to be, but it allows for a wide range of adjustment. If
you aren't comfy playing with it, don't. Pilot burner assenblies are fairly
generic and shouldn't be too expensive. (under $50.00) If you want some
added insurance against pilot outages, have a relight kit installed.
Generic, very easy and fairly cheap. And they work.
Probably, but I wouldn't go second-guessing until the whole problem is
worked out. Good luck.
Bull. My cheapie meter that I use as a backup can test them...(Cheap,
meaning under $190)
A bad connection at the techs interface...find a new one.
No one here can tell you, and the valve, could indeed have been bad, and
thus, the new thermocouple he installed prior can now be toast.
Replace the thermocouple and have someone that knows what he is doing test
the new one...or the existing one.
Thanks guy for you help. Here's where we are now.
Well apparently there was a recall on the unit in the late 80's. For one
reason or another whoever owned this house at the time got missed and the
manufacturer is no longer paying for the retro. I guess they had a lot of
pilot light issues with the unit and decided to retro them with an
electronic ignition. The tech said he could do it a lot cheaper with a
relight kit which someone also mentioned here. How reliable/safe is this
option. I am told the other route is quite costly, and i'd rather not be
downthere 2-3 times a day to light it.
BTW, I did get the check back and only paid for the service call so far. I
will have to pay for a relight kit later when it come in. How much do these
things run installed?
I mentioned a relight kit. It's under $100.00 over-the-counter, and takes
less than an hour to install. Here is the deal:
An electronic ignition lights the pilot (or main burner) on each call for
heat. When the furnace is off, there is no standing pilot. This is the
norm on modern day equipment. There is a significant amount of retrofitting
to install one on a machine without it.
A relight kit is just that... it "relights" the pilot in the event the pilot
goes out. It "piggybacks" right onto the older equipment, and wires into
the system transformer. Whenever a standing pilot is extinguished, it takes
the thermocouple some time (30-60 seconds) to sense the flame outage and
stop producing the 300 MV of electricity required to keep the hold-coil in
the gas valve open. When the thermocouple cools, the valve closes and
that's that... you have to manually relight the pilot. The relight kit uses
and electronic sensor (probe in the flame) to determine the instant the
pilot goes out. It then "sparks" through the same probe and relights the
pilot. If it doesn't do so within the cooling period of the thermocouple,
the gas valve will close as usual. Perfectly safe.
If your unit is over 10 years old, don't bother with the big electronic
conversion. You already have a new gas valve. Go with a relight kit and
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