I have a Gibson self contained GQ3R heatpump that has a defrost
problem. My question is, how do you diagnoise a defrost thermostat,
and how can you diagnoise the defrost board, or put the board into the
defrost mode without the defrost thermostat connected. I think the
defrost thermostat is a thermistor, is that correct?
If you were a tech, you would know how to run it though a test defrost
cycle. Just don't short the wrong terminals or you will be buying a lot more
than a DF board..... even if the problem is *only* the DF board.
Thanks Steve for a great answer! Just for the record I was a HVAC
contractor in the Nashville, TN area for 18 years and gave it up in
1989 for other interest. I know my way around the equipment very
well but am not familiar with the newer "to me" defrost board and
defrost thermostat. Almost every heat pump in that era used a
different way to do the same thing and it wasn't integrated onto a
single board. I can swap parts, but would like to diagnose before
throwing parts at it. By the way the board is part# 624633
Many Thanks, Everett
On Feb 17, 12:51 pm, firstname.lastname@example.org wrote:
On every board ive worked on, there are self test pins that you jumper
to put the unit into defrost initiation and defrost termination
modes . Im afraid that there are so many boards out there that a
Model Unit brand or part number on the board is of little help. Best
thing is to either get a manufacturers checkout procedure sheet or
find a local HVAC guy who has worked on these units who wont mind
sharing his knowledge with you. In closing, oftentimes when you look
at the board there will be 2 or 3 pins that are marked 'Test' near
them --- these are most likely the test pins for sending the unit into
defrost . I miss the old Ranco mechanical type Defrost Control that
was simply to engage defrost as well as troubleshoot .. such is
progress i guess. Regards.
On Fri, 25 Feb 2011 07:53:28 -0800 (PST), " email@example.com"
Thanks for the reply, I found the answer on the Nordyne site. Nordine
is the manufacturer of the Gibson line. There have been a bunch of
upgraded defrost boards since the date of manufacture on my unit, but
I think the test method is at least the same since my board, as the
test method I used was for a newer unit. There is an area at the lower
left of the board that has three terminals. They are marked ( T2 - Def
- test ). Using these terminals you put a jumper between T2 and
defrost with the unit in heat mode and running, then jump between test
and C to enter test mode, removing test - C connection as defrost test
starts. To stop test remove jumper between T2 and defrost.
Your right about the old Ranco board, I use to work on all brands and
would scratch my head on many ocassion wondering why every
manufacturer would do the same thing a different way,
On Feb 25, 12:45 pm, firstname.lastname@example.org wrote:
Glad you got your answer. Actually, I wasnt referring to the Ranco
Defrot Board, but, the old Ranco E15 mechanical type Defrost Controls
as thus : http://thermatixsupply.com/index.php?dispatch=products.view&product_id=30821
. It was nice and simple and you could run the Heat Pump Unit into and
out of defrost cycle by manually turning the Timer .
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