Справочник Пользователя для Friedrich PTAC - R410A

When  sluggish  or  stuck  in  the  mid-position,  part  of  the 
discharge gas from the compressor is directed back to the 
suction side, resulting in excessively high suction pressure.

Should  the  valve  fail  to  shift  from  coooling  to  heating, 
block  the  air  fl ow  through  the  outdoor  coil  and  allow  the 
discharge pressure to build in the system. Then switch the 
system from heating to cooling.

If  the  valve  is  stuck  in  the  heating  position,  block  the  air 
fl ow through the indoor coil and allow discharge pressure 
to build in the system. Then switch the system from heating 
to cooling.

Should the valve fail to shift in either position after increasing 
the discharge pressure, replace the valve.

Dented  or  damaged  valve  body  or  capillary  tubes  can 
prevent the main slide in the valve body from shifting.

If you determing this is the problem, replace the reversing 
valve.

After all of the previous inspections and checks have been 
made  and  determined  correct,  then  perform  the  “Touch 
Test” on the reversing valve. 

Procedure For Changing Reversing Valve 

1.     Install Process Tubes. Recover refrigerant from sealed

 system. PROPER HANDLING OF RECOVERED
 REFRIGERANT ACCORDING TO EPA REGULATIONS
 IS REQUIRED. 

2.      Remove  solenoid  coil  from  reversing  valve.  If  coil  is  to

 be reused, protect from heat while changing valve. 

3.     Unbraze all lines from reversing valve.

4.      Clean  all  excess  braze  from  all  tubing  so  that  they  will

 slip into fi ttings on new valve. 

5.    Remove solenoid coil from new valve.  

The  use  of  a  torch  requires  extreme  care  and  proper 
judgment.  Follow  all  safety  recommended  precautions 
and  protect  surrounding  areas  with  fi re  proof  materials. 
Have a fi re extinguisher readily available. Failure to follow 
this  notice  could  result  in  moderate  to  serious  property 
damage.

Touch Test in Heating/Cooling Cycle
 

The only definite indications that the slide is in the mid-
position is if all three tubes on the suction side of the valve 
are hot after a few minutes of running time. 

NOTE: A condition other than those illustrated above, and  
on Page 31, indicate that the reversing valve is not shifting 
properly. Both tubes shown as hot or cool must be the same 
corresponding temperature. 

Certain unit components operate at 
temperatures hot enough to cause burns.

Proper safety procedures must be followed, 
and proper protective clothing must be 
worn. 

Failure to follow these procedures could 
result in minor to moderate injury.

Sealed Refrigeration System contains refrigerant 
and oil under high pressure.

Proper safety procedures must be followed, 
and proper protective clothing must be worn 
when working with refrigerants.

Failure  to  follow  these  procedures  could 
result in serious injury or death. 

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