Image of a heat pump reversing valve
out of the box (click on the image to see the larger view). This valve
is about to be installed on a 20 year old Dunham Bush unit that the previous
valve was damaged due to improper installation. This valve is made by Ranco
but could also have been made by Alco (division of Emerson Electric).
This valve does not have the electric
coil installed which would be where the silver frame is. Once the valve
is installed and the system tested for leaks the coil will be added.
Replacing one of these valves is not a
job for the faint of heart. It is the most difficult repair that you can
make on a heat pump above and beyond replacing the compressor. Installing
the valve is difficult enough, not burning it up is even harder. It requires
very good brazing skills and media to cool the valve while brazing. On
one job we used snow to cool the valve between joints.
There is a right and wrong way to install
the valve. On most system the valve is installed so that with no power
to the valve it will be in heat mode, Rheem and Ruud (don't ask me why)
the valve is placed so that cooling is the default even if it has a relay
to invert the 24 volt AC "O" signal. On Rheem and Ruud they also use a
high voltage coil as opposed to 24 volts from the inside, so if the unit
is in heating when unit power is removed it will revert to cooling instantly.
Which means that on other systems there is no such thing as the reversing
valve "reverting to cooling" or "going into heating mode" It will only
go into cooling with a signal to the coil otherwise it is in the heating
mode.
The way the reversing valve works is the
solenoid valve opens pressure ports to operate a nylon slider in the cylinder.
This sleeve can jam or bind half way (called "wind milling") and will over
heat the compressor in a few minutes. Once this happens there is little
chance that the valve will work again. If the valve is over heated when
being installed it is trash and will never move. If the system is very
contaminated after a Burn Out it may stop the valve form working but there
is the possibility of getting it to work again after several cycles. It
is possible for the valve to stick in the cooling mode but it is more likely
to stick in the heat mode.
To do the job replacing this valve we
charged $800 and that included adding a TEV for the heat mode to replace
a capillary and adding a start kit. The unit that this went into is in
excellent shape and has a suction to liquid heat exchanger to increase
efficiency. This heat pump is used with an oil furnace.
This page will be updated soon
Good Luck Scott
To identify the components of your gas furnace and gas
valve system click here.
If your heat pump forms
ice outside in the heat mode click
here.
If your air conditioner or heat pump ices
up
in the cooling mode click
here.
If you have
air conditioning water leaking problems
click here to solve it.
To ask us about heat pump or air conditioning problems
click
here.
For other heating system problems click
here.
Any other questions feel free to contact us by
any of the means below. good luck Scott.
If you were looking for Ice
Machine repairs click here.
This text written by: Scott Meenen * G & S MechanicalWritten By: Scott Meenen N3SJH of:
G&S MECHANICAL SERVICES.
Specializing in Mechanical, Controls and Electrical Modifications Of
Heating, Air-conditioning, Refrigeration, Cold storage,
Ice Production and Food preservation.
Anything having to do with Heat and Energy.
Serving MD, DC, and Northern VA.
Contact us by pager: 1-877-467-2914Page us by e-mail 4103560613.3732505@pagenet.net 240Chrs max.
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