On Mar 26, 7:20 am, Ken wrote:
Mike Mills wrote:
Hello,

We bought a house a while back, and part of the deal was to fix the air
conditioning unit (heat pump), on the advice of our home inspector.

The outside unit was replaced, and it is physically quite a bit larger
than the previous heat pump. (I couldn't find any performance
information on the stickers, just part numbers, and I plan to look that
up tomorrow.)

Fast forward to now: Spring has arrived (Northern Kentucky), and the
house is in the low to mid-80's inside with the air conditioner on.

I've been doing some homework, and think I understand the components
better now (compared to when we bought the house.)

I took the panel off of the air handler unit (located in our basement),
in order to have a look at the evaporator coil. The coil has rust on
the copper tubing, and it looks like the fins are dirty on the inside
(it is hard to get a good look though.)

Notably, the air blows considerably harder through our vents with the
panel off of the air handler - I assume that this is a sign that the
evaporator coil is "dirty"?

I also wonder if there might be a refrigerant leak, as the big copper
intake tube does not feel very cold at all.

Having said that, I have one important question, as this pertains to
whether the people who installed the new heat pump did their job right:

1. Everything I've read in the last couple of days says that you should
replace the evaporator coil unit at the same time you replace the
outdoor condenser / heat pump. The installers did NOT do this - they
just replaced the heat pump. SHOULD they have replaced the evaporator
coil? Is there a strong enough reason to do this that I would be
justified in demanding that they replace it now?

2. I've also read that it is important that the evaporator coil must be
carefully matched in size to the condenser / heat pump. Unfortunately,
neither of my units have any performance information on them, but I do
have the model numbers, and so I will try to find that information out
soon. But, I can tell you that the new heat pump is considerably larger
(physically, at least) than the old one. Assuming that the new one is
(significantly?) larger (in capacity) than the old one, and that the
existing evaporator coil was in fact matched to the old, smaller, heat
pump - does this also justify me in demanding that they (the installers)
replace the evaporator coil with a new (matched) unit?

When we bought the house, I didn't understand how the whole
heating/cooling system really worked. They said they would replace the
heat pump, as the old one was making strange sounds. However, it would
seem to be a bit negligent to blindly hook up a larger heat pump to an
old (rusted & dirty) evaporator coil. If this is the case, I'm also
concerned that this may affect the life of the new heat pump (being
mismatched.)

Anyway, I would appreciate any comments on this, particularly on what
the installers _should_ have done (if different), as well as any
suggestions on what to do next.

Thanks for any help!

Mike

Just curious, how long ago is a "While back?" I don't know about heat
pumps, but I don't believe a typical AC unit can be "Properly" charged
and checked unless the the temperature is over 70 degrees. Before I get
flamed, I realize there is a capacity to which such units should be
charged, but it is only an approximation if I am correct.

From what you have stated, I would immediately contact those
responsible for the installation of the new heat pump. It sounds like
you got short changed. If the evaporator coil is clogged, that is NOT
an acceptable installation in my book.- Hide quoted text -

- Show quoted text -


This is a good example of how not to do things when you find an
inspection defect that has to be fixed on a home purchase. You
should have negotiated a credit from the seller, based on estimates of
what it would cost to repair the unit. Then, you could have chosen
your own contractor, made sure they replaced the whole system, etc.
For example, how old is the rest of system? If it's 20 years old, you
would have been better off changing the whole works, including
evaporator and air handler. As a seller, I would not feel obligated
to do all that work. I would want to hold down the cost and agree
to only replace what is clearly defective. Meaning, I would give you
a credit for the cost of repair and then you can choose what to do.
Most likely, you'd pay some more and then replace the whole thing,
have a more efficient unit, have it done right, etc.


I agree with the advice to start with the company that did the work.
See what they say and get as much info as you can. Regarding the
system blowing more air with the blower door off, that is not
necessarily a sign of the evaporator being dirty. Any system will do
that. With the door off the blower only has to suck air right there,
while with it on, it has to pull it through the return system, which
offers much more resistance, hence less air output.