I am wanting to check to see if there is a possible problem created in
my Air Handler which might be happening when the Heat Pump enters into
a defrost cycle, but I'm not sure how long I have to wait until one
The weather here is highs in the 50's and lows in mid 30's (northern
I have seen two designs for triggering defrosts but I'm not sure which
Tempstar uses. I am suspecting its timed, but does that mean I would
only need to wait about 2 hours till one occurred, or do they only
start when the outside temps get down to a certain degree?
This is the unit with 10 year compressor warranty and R410A
On Nov 9, 7:31 am, snipped-for-privacy@-insightbb.com (The Freon Cowboy) wrote:
Because the 'installing party' is who I suspect may have installed it
incorrectly and I don't trust whatever answer they would give me.
So I am asking here. I couldn't find any info on it on the internet,
On Nov 9, 8:53 am, email@example.com wrote:
Don't know that model in particular but here's some generalities. The
air handler is typically not aware that the outside unit has gone into
defrost. Most, no matter how they trigger a defrost cycle, they
usually will have a way on the defrost board to start the cycle.
That's so the service guy doesn't have to wait for one to initiate.
The paperwork with the unit should give some details or you might find
it on the web.
Hi let me first say that heat pumps I have never work on one so I could not
tell you didly, however electrical trouble shooting that is different story
You have stated that man did not check anything but change the fuse and out
he vent, well on normal service call that is all he may need to do
and as for myself I would have check current and fuse rating, fast blow
fuses can some time blow for no reason, you can have spike come down
the line and if fuse is rated close to the running current it most likely
will open/blow, if you have something wrong in system it would have most
likely blown right away. As far as defrost well that might take day or days
depend on Humidity's in you area, I don't think that you would like to keep
paying man sitting there waiting for unit to go into defrost cycle I
definitely would not.
Good luck Tony
you can force the heat pump to go into defrost mode. First I would only
perform this if you feel comfortable working around 240VAC. turn your tstat
heat up( make a call for heat) the heat pump should be running now then you
need to look at heat pumps electrical schematic and find the out door fan
circuit. pull the power to the outdoor fan ( normally on the defrost board )
this will cause the outdoor coil to frost up even with moderate outdoor
temps the heat pump will only go into defrost when the coil is cold enough
now look on the defrost board for the force defrost function (after you see
frost on the coil. once you force the heat pump into "defrost" you must plug
the out door fan back in.
ok that's how you would check out your defrost operation, but what is your
concern with your air handler? please write back before you try to check it
out so I may help you diagnose your problem. Robert Moffett
A 5 amp fuse was found to have shut down the entire system. I called
the installer of the 8 month old HP to do a service call. The Air
Handler is 9 years old.
Service guy only opened the AH first said, "This is a Trane unit, you
better call a Trane guy because I won't have any parts to fix it."
I thought this sounded very strange as I asked him specifically before
hand if he would be willing to take a look at the unit. Having done my
research before hand I then mentioned that there was a 5 amp fuse in
there that might be bad. Thats when he mentioned "I'm looking at that
right now." And I saw him pull it out and check it. It was indeed bad
and was replaced. He then had me restart the system and it worked.
My problem is that he then simply asked for his check and wanted to
go. No other checks or tests to the system. He waited until the HP
came on, then was out the door. He didnt even wait around until it
cylcled through a complete heating cycle. I kept asking him about what
may have blown the fuse and he had no real idea. I had suspected it
may have been something to do with the defrost cycle, but as far as I
know, he did nothing to test that theory, or even test anything else
like refrigerant levels, etc. He charged a full service call amount,
but was gone within 15 minutes, literally.
So, I am wanting to know how long I would have to wait until the unit
goes into its defrost unit, as evidence that the fuse didn't blow
because of some issues with its defrost cycle. (Its only been in heat
mode about 3 weeks and its not been below 32 yet)
thats the background
I would not call that company again, except talk with the owner and ask for
a refund. the service tech should have been able to find the short and order
parts if needed. first of all the 5 amp fuse was blown you at one point had
a dead short. The fuse that blew protects the 24 volt transformer. if the
system has been running in heating for three weeks in heating then the
system has more than likely has gone into defrost mode more than a few
times. there are a few things you can do to try and find the short but if
its been running ok for three weeks now you have a intermittent problem. I
would first check the heat pump. turn off power to the heat pump and air
handler (at main fuse panel) remove the side panel to the heat pump you will
be looking for the smaller wires (low voltage) first look for any wires that
run next to the coil, or are touching the coil look for worn spots on the
wires that are touching the coil, this would cause a dead short and blow the
fuse in the air handler. this is the most likely scenario let me know what
you find and we can move on to the next step if no short is found there.
Although it sounds like the guy did no diagnosing, the 15 min and what
you paid is not the issue. I mean, a well educated tech could find the
problem quickly while the 21 yr old new techie might spend 4 hrs
finding it. Which would you feel better paying the "full service call"
By the way, since Im in this area, which company did you call?
Why would you put a new HP on a 9 yo air handler. Is the system an ARI
match. Sounds like you are in for many years of problems, and possibly even
higher electric bills. I do believe your warranty may be voided too!
On Thu, 08 Nov 2007 20:35:17 -0800, firstname.lastname@example.org wrote:
They used demand defrost then switched back again to time/temp. After
your coil sensor reaches a preset temp, your timing starts. Its prob
set for 30 mins but can be 45 or 90. If the sensor opens at any time,
the timing starts over again before you will see a defrost.
You can also speed up the defrost timing with the test pins but I dont
want to go into how to do it.
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