Proper Crossover installtion

[collins2009]

Hi, I have seen pictures of crossover installation on doublewide mobile homes and mine doesn't look right. Also, one half the the house doesn't have much air at all. I don't feel any leaks. I would like to know how you set up a crossover as if I didn't have one, so I can see if mine is right and if not fix it right myself. I would like to know where its supposed to be located and what fitting to use and their size. I live in a 28x56 home and have a 3 ton heat pump.

Thanks
John

[tritontr]

Collins where the crossover starts is on the side with the furnace then where it attaches to the other half is usually at a spot in the ductwork that has been chosen by the factory engineer to meet the required airflow for that half of the home. The size of crossover pipe can be calculated by looking at the round or square opening on each half where it attaches. If it is square you can take that size and convert it to round if you want to connect with round duct. The preferred method is to use metal round pipe and fittings wrapped with insulation on the outside and supported off the ground with metal straps. All of the above is contigent on that your main ductwork on both sides was installed by and engineered by the factory. You can also have metal duct work made up that has dampers and turning vanes installed that control the amount of airflow deliverd to each side but I would consult an HVAC tech before taking on that expense.

[collins2009]

Okay, the installed fitting are very small and rectangle and the crossover is 5 times bigger than the rectangle fittings. And I don't hardly have any air on the other side. What I mean it is nice and cool on one side and hot on the other.
If I installed the round ones, it can't come from the side of the duct work as they are now. So do I install a round directly below the Main air "box" in which the heat and air are installed? I believe the whole setup was done wrong.
Thanks Collins

[Robert]

Hi,


You can install round by using an adapter fitting connector for the rectangular which will convert to round.


Then connect a 90* ell at each connector and round metal duct between. It comes in 4 ft. sheets .


Use sheet metal screws and foil tape, then cover with insulation backed with vapor barrier.


Usually 14" is the avg. norm.


IF you have concrete piers in the way, then flex duct will be needed.


IF you have flex now and it is too big, it will sag and kink and restrict airflow.


I'll see if I can find my article info I am still trying to get posted in articles section on this.



Thanks,
Robert