not sure what's wrong

Posted by KJPRO on May 16, 2008, 1:42 am

> That sounds like something you'd do at summer camp. Stick the unsuspecting
> system's bulb in hot water, and see if the valve opens.
> It sure would be a good diagnostic for a TXV, though. Why not just unclamp
> the bulb, and hold it out to the warm attic?
> OTOH, it may be the system is under charged. Or the condensor could be
> dirty, and supplying hot refrigerant.

Why don't you get a clue before spewing more shit from your mouth?

Posted by KJPRO on May 16, 2008, 1:41 am

> If you're determined to do something with the bulb then stick it in a bowl
> of hot water & see if it will lower your 40 + deg. superheat. Have I
> mentioned that it could be just under charged.

40' lineset and installed in an attic....

You can bet on the system being undercharged!

Posted by KJPRO on May 16, 2008, 1:39 am

> That brings up a good question. Some of the guys I work with insist
> on mounting it on a horizontal line, offset 45 degrees, and downstream
> of the pressure tap.... unless the manufacturer specifies otherwise.
> Others mount it vertically upstream and say there's no difference. I
> side with the first group. I cleaned and re-insulated/taped the bulb.
> comments?
> Yup... horizontal at 10 or 2....the bulb should have 2 lines coming out of
> it... a real short one crimped off, and a long one that goes to the TXV...
> its preferable to have the long one on top. BTW... there is supposed to be
> metal to metal contact between the bulb and the suction line where it
> comes
> out of the evap coil, with insulation wrapped around the whole mess.

"10 or 2 is a little boyond the 45 degree point. I'll put it there and
see if it makes a diff."

ICP (Heil) coils (that have factory installed TXV's) normally have an
indentation for the bulb. This makes it a no brainer.

Posted by on May 15, 2008, 12:08 pm

> richard...@yahoo.com wrote:

> > Most of my work has been new construction and very little service tech
> > so forgive me if this is too simple. =A0My ex-wife called me a few days
> > ago and said her heat pump wasn't cooling. =A0She said someone replaced
> > the compressor, which made it much better, but it's still not cooling
> > like it should. =A0So I thought that unless I want to give her even more=

> > of my hard earned money, I better load up the truck and head over.
> > Here's what I found. =A0It's a 3 ton 10 seer HEIL split system heat pump=

> > with a TXV. =A0New copeland recip compressor and new dual cap. =A0Coils
> > are clean, filter is clean. =A0I put the guages on and that's when I got=

> > a little confused.
> > outside air temp - 81
> > inside air temp =3D 78
> > Outdoor humidity: ~70%
> > Suc Pressure - 64
> > Suc temp - 80
> > Liq Pressure - 200
> > Liq temp - 87
> > Condenser TD - 13
> > Evaporator TD - 14
> > My handy Trane charging chart shows it being slightly overcharged....
> > but shouldn't be enough to give me such a low TD across the evap.
> > Rather than just start fiddling with the charge I thought I might want
> > to actually try to figure out what's wrong with it.
> > The only other thing out of the ordinary is the condenser fan was
> > replaced with one that's 75 rpm faster. =A0It calls for a 1075 rpm and
> > has a 1150. =A0In my brief experience I believe that won't have a big
> > effect.
> > any ideas?

> I'm thinking your TXV isn't opening enough to fill the coil completely wit=

> refrigerant, hence a low TD across the evaporator with a high superheat...=

> [low performance.]
> All other signs seem normal, except that since the evaporator isn't gettin=

> enough refrigerant, I'd see a low head pressure because the system isn't
> picking up enough heat......
> Thinking about Noon-air's recommendation, I'd likely go his route but
> install a new TXV while I'm there cleaning / checking the screen before th=

> valve.
> --
> Zyp- Hide quoted text -
> - Show quoted text -

That makes perfect sense. When I go back I'll do that.

Posted by Gary on May 15, 2008, 2:20 pm

I think you're trying to cut a piece of grass with a chain saw.
All the guys have brought up good points but there's nothing in your
numbers that negates the possibility of a low charge which would take all
of five minutes to try. If that doesn't work then go get the chain saw.

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not sure what's wrong - Page 6