Welcome! Here are the website rules, as well as some tips for using this forum.
Advice on a Carrier rooftop unit Gas Valves failing
I am really confused on this. We have a customer with 7 Carrier model 48TCED16A rooftop units. The units are 8 years old and one has had the gas valve fail three times. We have checked the voltage and it is the same model and age as the other 6 I am kinda stumped what to tell the owner. When I talked with the distributor, their response was "Hmmm Thats weird."
Ray Wohlfarth
Boiler Lessons
Click here to take Ray's class.
Click here to buy Ray's books.
0 ·
Comments
Boiler Lessons
Click here to take Ray's class.
Click here to buy Ray's books.
I had Carrier valve fail, old HVAC. Nat gas . City had low pressure main that rusted underground, groundwater dripped into main, evaporated, then condensed in winter inside cold $300 valve on roof. Corroded inside.
Water vapor also condensed inside gas meter and it froze up in winter , stopped delivering gas. Gas Co came out and put electric heat tape on meter. Was restaurant, used up to 900k BTU/hr nat gas.
Said if problem continued they could add methanol? bubbler to absorb moisture from the gas. I asked for it but they didn't want to add it unless more problems.
Not knowing any better I did it their way, valve didn't work next heating season. I should have sent them a bill.
What exactly failed?
End of the line or in the middle?
@Leonard That happened to me weird Gas company fought with me until he saw pressure drop
@JUGHNE This takes care of south wing of tower. The building has three rooftop on each tower Got me scratchiung my head
@pecmsg gas valve looked like it did a years ago. Ready to get an exorcist
Boiler Lessons
Click here to take Ray's class.
Click here to buy Ray's books.
How long did it take each valve to fail ......# months?
Did it fail during heating season, or at 1-st firing of new heating season?
What was failure mode ....... electrical open/short OR mechanical
Just replaced a pair of Trane negative pressure regulators because the plumber put 2# regulators on a 4# system & the diaphragm blew & put the full 4# on the gas valve. <smh>
Might apply higher pressure to valve.
people slap there meters on and see the digits move or the needle swing (for old guys like me) and they thik it's good enough. Its not
Boiler Lessons
Click here to take Ray's class.
Click here to buy Ray's books.
Turns out there was a vent for the regulator that ran back inside the outside wall of the house up to the roof had comes loose and filled with water and froze.
There are filters for natural gas you could also try. Not sure but SOme might have separators with a peacock to drain them.
Otherwise, is there a aftermarket universal gas valve you could instead to rule that out?
They all burn the same gas, have same electrical supply. What's different?
Is this unit fed gas first?
Have it's own regulator?
Strange low voltage problems from bad XFMR or board?