ac Freon refill

[pepmyster]

Ok, I'll go over this again this weekend before anything is done. I'll look again for restrictions of air flow. It's under the master bed in the forward berth.

[tomschauer]

actually, when the coil starts to frost, it continues to reduce the air flow as the frost expands, thus making the problem worse, until you end up with a block of ice for a coil.

[pepmyster]

Ya, then it leaks out , the water never see's the pan and leaks onto the carpet. ARGGGGGGGGG!!!!!

[km1125]

QR_BBPOST Ok, I'll go over this again this weekend before anything is done. I'll look again for restrictions of air flow. It's under the master bed in the forward berth.

You have to look at both ends of the air distribution. There's typically ONE fan, and it has to do all the "pulling" and "pushing"
So it may not be air being blocked going INTO the evap, but air being restricted going OUT of the evap (to all the distribution registers). Any blockage or restriction BEFORE or AFTER the evap is suspect.

Also, If air is leaking around the evap, then it's not going THROUGH the evap, which is reducing flow there. The fan may still be blowing/sucking, but not actually all of it THROUGH the evap.

[km1125]

QR_BBPOST actually, when the coil starts to frost, it continues to reduce the air flow as the frost expands, thus making the problem worse, until you end up with a block of ice for a coil.

This is true, but in all practical terms, you have to even get it down near freezing before it starts to frost up.

If you take a certain block of air (cu ft, room size, whatever) it contains a bit of moisture. Dropping that moisture in the room from 'room temp' (70, 80, 90?) down to below 40 takes 1 BTU per pound of water, or about 8 BTUs per each gallon. To just get that water to CONDENSE on the evap, even if it's still well above freezing (say, at 40 or 50F) takes ANOTHER 970 BTUs per lb of water, or 7,700 BTUs per gallon. Now, to get that to be freezing up on the evap takes YET ANOTHER 144 BTUs per lb, or 1,152 BTUs per gallon. None of that is actually factoring in actually cooling the AIR, but cooling the air is less of a challenge than cooling the water in the air, especially in humid environments.

So if you have a 12,000 BTU air conditioner, a substantial amount of that capacity is just sucking the water out of the air (which also effectively drops the air temperature, which is nice). But that also means that enough air flowing through the system will NEVER cause it to freeze up, nor get close to it.

[pepmyster]

So then, Went to the boat, got to the ac unit. Checked the coils, I used a mini shop vac that I have on the boat. Vacuumed the coils and made sure none of the fins were causing air flow problems. Then, I went to the shower sum pump, where the ac drains into. Put the vacuum on the line between the sump and the ac unit. Cleaned that out. I sure that was never done, I mean, who does that right? Anyway, I ran the unit for about 3 hours, no frosting or over spilling of water. All I'm hoping for is that this solved the problem, oh and yes, it's R22.