Just had a tech check out one of my 3 HVAC systems. When the house was
built the contractor switched outside units between the upstairs and
basement so upstairs was too hot. I had them switch out the obviously wrong
sized outside units. I asked them if anything inside had to be switched out
and they swore everything was ok inside.
Upstairs never cooled well but we were never used upstairs much until now.
So I had someone come out today and told him the story. He says the
metering unit orifice (piston) is too small upstairs and needs to be
replaced with bigger one at a cost of $193 for the part and $533. I just
called another guy to come in for a second opinion but I was wondering if
the estimate sounds reasonable if indeed this is the problem.
Thanks in advance for assistance.
Not sure what market you're in, but in the Rochester NY area, that sounds a
bit high. Some of the coils I've installed had two orifice, provided. So
I've got a couple spares in my tool box. As to the install, an hour or two
at the most, unless it's a dificult job to get to the indoor coil.
My sense is that real techs don't post to alternating havoc. Me, well, I've
done some AC but I'm still very much the beginner. I'm drawn to alt havoc
like gawkers to a car wreck. I know full well it isn't doing me any good.
But, I'm drawn like a moth to a candle.
They were particularly harsh on you. I never could understand why they felt
the need to be so abusive. Childhood trauma? A need to get even? The amount
of virulence and testosterone in that group was too much for.
I admire you for hanging in there and trying to be helpful.
I have a few questions:
1. What is the size (Tonnage) of the upstairs and basement condensing units?
2. What is the size (Tonnage) of the upstairs and basement evaporator
3. Was the bid to replace the piston only or to replace the total metering
I have another tech coming tomorrow. Unfortunately I don't have the
expertise to interpret the labels on the Carrier outdoor units. The one
thing I did notice is Piston ID 57 on the larger unit label and Piston ID 52
on the smaller unit's label. The part his receipt says I need is a #57
Piston. I asked him if the units are mismatched shouldn't we switch out
both pistons but he said an extra large one in the smaller unit wasn't a
When the next tech arrives tomorrow I will try to get the tonage of the
condensing and evaporator units in both locations.
When you get the model numbers from the condensing unit and the evaporator
coil or you have to do is contact your Carrier dealer and they should be
able to tell you what Carrier recommends what size piston you would need for
To replace a piston all you have to do is pump down the system, if you can,
then open up the connection at the inlet of the coil then drop the existing
piston out and install the new one and then close up the system them put a
small vacuum on the line set then open the line set then top off if needed.
I got some answers. Both inside units are idenditcal 2 ton units. Basement
outside unit is 1.5 tons. Upstairs outside unit is 2 tons. According to
the tech that was here today, it was common when my house was built 10 years
ago to use an oversized inside unit to squeeze more efficiency out of the
system on the small tonage outside unit.
He washed outside coils and checked freon on all 3 systems. Basement was
slightly low. Upstairs was way low, taking about 3 pounds of freon. None
of these systems have been checked for8 years because the guy I had come in
to check them when the house was 2 years old did nothing so I pretty much
gave up on HVAC contractors. Plus we hadn't been using the upstairs much
until this summer.
The technician today's philosophy is (and I am sure many will disagree) is
the first time he adds freon to a system that hasn't been serviced for such
a long time, he will not try chasing down the leak because he probably won't
be able to find it unless it just started leaking. He says if it warms up
again upstairs, he will chase down the leak but he suspects it is the inside
coil and he says carrier charges so much for that inside coil that I might
be better off replacing the outside unit too.
Right now things are plenty cool in the house.
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