A/C volume of air from ceiling

[Bob K4TAX]

I won't accept a puncture-type saddle valve. They will LEAK! Cutting the line and brazing in a valve is the only way. Please do not put any AC sealant in the system. Should the refrigerant ever need to be recovered, it gums up the recovery equipment.

Based on the AC DOM, ours took 7 years to "leak down". It must have sat in a warehouse for at least a year or more before being installed. I'll bet on another 7 years for $150. YMMV

In doing some investigation this evening, I removed 4 of the round ceiling directional air vents. The original installation appeared to use grey fabric duct (duck) tape and not metallic HVAC tape between the overhead rectangular duct and the vent frame. I discovered a lot of air from the overhead duct was not making it to the ceiling-mounted directional vents.

I do have a roll of metallic HVAC tape. The project for Monday is to pull all of them and make proper seals between the overhead duct in the ceiling and the directional vent frames.

Bob

[dward51]

If you do a complete recharge after installing a service port, here is the Dometic chart by model that shows the amount of R410 to use for a complete recharge (by weight).

[Larry-NC]

Originally Posted by dward51

Just a FYI, but Dometic does list the amount of refrigerant for their various models in the install manuals (It's in the one I downloaded yesterday). I would think the evacuate and install a permanent brazed on service port would be a better option than the bolt on.

The brazed-on port is definitely better. When I bought the house one unit (residential!) had only a clamp-on saddle port. Apparently (judging by placement) it was added after the fact. Some years later, the guy I use (right out of VoTech) determined that it was suspect and brazed one on instead.

Really, you're at the mercy of the tech you can find to do the job. If he only knows one type or likes one type, that's the one you will get.

[Bob K4TAX]

That Dometic chart is great! Thanks for sharing.

FYI - the information as to type and amount of refrigerant is posted on the unit. Remove the cover and look. Also the amps will be there too.

By the way, if your power system has the ability to monitor AC AMPS you can see the starting and running current of the fan, and then the starting and running of the compressor. If the compressor current is low, based on the chart or label, that is a good indication the refrigerant charge is likewise low.

If the HVAC tech wants to make a fast buck, he will strap on a puncture valve, hit it with refrigerant, and say you owe me $xxx.xx, and be gone in 30 minutes. Otherwise, he will be there for about an hour or so to do the proper job for about the same price.

Bob

[Dijoeboss]

Ok, one problem fixed, had A/C service taps sweated in and system evac and recharged!! Now the air is blowing cold again!! Found there is lots of cold air blowing out from under the roof unit, next repair is to reseal the unit to the roof!!

[Larry-NC]

Originally Posted by Dijoeboss

Ok, one problem fixed, had A/C service taps sweated in and system evac and recharged!! Now the air is blowing cold again!! Found there is lots of cold air blowing out from under the roof unit, next repair is to reseal the unit to the roof!!

This is real easy. There is a high-density, closed-cell foam rubber seal between the A/C and roof, going all the way around. To set it properly, it must be only partially compressed. Too loose, it will leak. Too tight, it will leak. To adjust it, you loosen or tighten the four clamping screws from inside the trailer. One source says to tighten them until they are snug, than one quarter turn further.

Hopefully it hasn't been tightened too tight, causing the gasket to take a "set" and not resume original shape when the unit is loosened.

[NoviBill]

My 16 year old Dometic 13.5btu failed a few weeks ago. Ordered a from eTrailer:

Advent Air Replacement RV Air Conditioner for Dometic Setup w/ Start Capacitor - 13,500 Btu - White

Direct plug compatible replacement for about $700. Took about 2 hours to replace. Hard part was getting the new one on the roof.
Take the inside cover off, unplug the external AC from the internal controller and distribution portion. Remove the 4 bolts holding the AC in place and go up on the roof and gently rock until it comes loose (it is just set in place, the inside bolts hold it down). Reverse to install. My old unit was about 85lb, new one is 65lb.

[dave-g]

Originally Posted by NoviBill

Advent Air Replacement RV Air Conditioner for Dometic Setup w/ Start Capacitor - 13,500 Btu - White

Direct plug compatible replacement for about $700. Took about 2 hours to replace.
Take the inside cover off, unplug the external AC from the internal controller and distribution portion. Remove the 4 bolts holding the AC in place and go up on the roof and gently rock until it comes loose (it is just set in place, the inside bolts hold it down). Reverse to install. My old unit was about 85lb, new one is 65lb.

Amazing sound reduction! Did you get the heat pump or ac only model?

[NoviBill]

Originally Posted by dave-g

Amazing sound reduction! Did you get the heat pump or ac only model?

AC only.