fcc & headmaster ?

[hvac wiz 79]

why would a 1 fan cond unit have both ? ... seen it recently & I couldn't quite put my finger on it ... system had no issues but while passing time on a dif unit I happen to gaze over & notice

[dangpgt97]

Sounds like a bad idea to me. There was some talk on here awhile back about manufacturers cycling one of two fans along with a headmaster to reduce refrigerant charge and gain some energy efficiency the months you don't need to be running it.

I've seen this setup a couple of times with a single fan using both a fcc and headmaster. There's just too much of a head pressure swing too quick. The two controls fight eachother. When I see this it tells me there's something wrong with the installation or there was a problem with the unit when it was new. Unless it was intentional by the manufacturer.

Any system with the properly sized reciever should work great with a condenser flooding device alone.

[hvac wiz 79]

thanks for reply ... all 5 units were set up the same, the 6th which was the only non original compressor didn't have the fcc ... guess that tech figured it wasn't necessary considering .

[jpsmith1cm]

I don't see the point if it myself.

That said, I have seen it more times than I care to count.

[mizzouhvac]

I see that alot in my neck of the woods too. I do not know the reason myself why other techs do this. My best guess is they do not understand how a refrigeration system works and this was their best guess at a repair..? When I find a system like this I always explain it to the customer and make the appropriate repairs.

[smilies]

So now I've run across this. The units were Trenton with factory Headmasters at 215# and fan cycling control set at 100# cut out and 180# cut in, R-404a. Comps are air cooled. They've been like this for a while, I assume.
I want to raise the CFM to cut out at 10# above the Headmaster, like I've done for other units that had multiple fans. Except, what about the comp? The other units I've done were either gas cooled so it did not matter or had 2 or more CFM's and the one by the comp ran 100%.

[Snapperhead]

Back in the day ... I added a fcc to a walkin unit before i knew the facts. Now i look back i think i should have replaced the headmaster