1961 cadillac conversion

[Al9]

Malfunctioning cycling switch?

[cadillac matt]

the condensor is cold and all the air is going through it. i sprayfoamed the core to the case so it's completely airtight. the way the system is, is 2 separate air ducts and vents and 1 fan. it even has 2 separate control heads for heat and a/c. i think it may need more airflow, but i'm not sure how. if it was lack of airflow, it would seem like the air would be really cold, just not enough volume to cool the car. the cycling switch seems to work. it cycles on and off at about 15 psi. is that too low?

[tbirdtbird]

Long thread. Has re-heating such as faulty blend doors etc been discussed. Sorry if it has been addressed

[bohica2xo]

15 psi 134a is around 15f.

If your lines in & out of the evaporator are cold enough to freeze atmospheric moisture, then the core is that cold as well.

If you are blowing air over an evaporator that is that cold it will be very cold on the discharge side. Well, at least until the core freezes solid from collection of atmospheric moisture.

But since you insist that all of the system air is passing through the evaporator core, wait a few minutes. When the core ices over you should see a big reduction in airflow from the vents. Shut the system down, and watch the condensate drain.

If your problem is ice formation, re-adjust the cycling switch to close around 34 psi.

[ice-n-tropics]

in humid weather with humid air bypassing evap, and fresh air entering fan (Window partially down on recir.), frost will blow out of louvers.
hotrodac

[Tim]

in humid weather with humid air bypassing evap, and fresh air entering fan (Window partially down on recir.), frost will blow out of louvers.
hotrodac

Hey Ice. Hope all is well and fishing is good.

[cadillac matt]

the way the system is designed is that 1 fan blows through 2 separate sets of ductwork. a flapper door switches between them with no blending. so on hot all the air comes out the floor or defrost, and on a/c all the air comes out the dash vents. all that seems to work. i had considered the core freezing up, but it doesn't seem like the airflow ever changes. could the core freeze internally? would a partially blocked core cause this? the core was modified to fit by old air products to accept the ot and the accumulator. do i need more air flow? should i push this thing out side and light a match to it?
thanks guys for all your help.

[bohica2xo]

I have no idea what sort of core they provided. A large, folded fin plate style evaporator like this was common for cars that size:


https://www.rockauto.com/en/moreinfo.php?pk=814196&cc=1445060&jsn=917

[cadillac matt]

it looks like a original type core with the inlet and outlet changed. i don't believe it's a parallel flow type. it's big.

[cadillac matt]

final update.
after all the f-ing around, i figured it out.
i bought a brand new custom evap core for this project. the core was partially obstructed. when the system was working, only the 1st inch or so of the core would get cold. the rest would be room temp. sent it back and they made me a new 1.
success!! a chilly 32* at the vents today. woo hooo!!!