Do it Yourself: Re: [DIY] New Roof HVAC== Help please

28 December 2012

Re: [DIY] New Roof HVAC== Help please

Roof top units are another of those great ideas that did not quite live up to expectations. They were also often set outside of the dwelling and connected to the duct work through a hole in the foundation or side of the house. The elements took their toll and servicing during extreme weather conditions was a real bear. I darned near froze to death getting heat back for an elderly couple during near blizzard conditions. I take it you have either a flat roof or one with very little pitch and are probably planning to go back with a similar unit. Roof top units were actually intended for commercial buildings but people being what they are, a profit potential was seen in the small home market and promoted as a way to save space in smaller houses, but most eventually started to leak and cause more internal damage then they were worth.

If you managed to get 30 years out of your unit you are well ahead of the average curve, at least in this part of the country, of course where you are living is effectively dessert and so a leaking roof is probably not an issue. On a unit of that age I would seriously consider replacement.

Dale in the Flatlands.

mountain953346 wrote:

We have a 30+ year old heater and a/c gas fired, on the
roof.

I really hate to bring the list back to total DIY after
such stimulating conversations of the last week or so...but:

We have decided that it will be more cost effective and
less frustrating to replace the unit instead of starting
the "common" repair cycle which we anticipate with such
an older unit will continue into the thousand dollar
range)current repair estimate for control board and
transformer is about $300 DIY...easy fix so it seems...
but the compressor is 30+ and estimated lifetime is 15-20
years. And we will not now what else is wrong until we
get the board replaced...etc

Does this lifetime estimate seem reasonable to you?

And we are thinking of a Payne heat pump of the
model series PY3GNAA48090N 4 TON 13 SEER GAS/PACK
for about $5000...

Any thoughts about unit, price, repair versus buy would
be most welcome as we sit here "freezing" in SoCal!! LOL

Rich and Kate