cold outside temerature=cooler down?

[29mv29]

does this make sense? if the ambient temp is 14 degrees F, could this cause higher cooler temp? What should I look for? any suggestions would be greatly appreciated.

[passandscore]

Check to see if the system is fitted with a headmaster control or dual valve system for low ambient conditions. If it is equipped you may simply need to add enough gas to overcome the ORI pressure setting. See attached.

[29mv29]

Exactly, I lowered the dual pressure controller to 0 and 10. With an outside unit using 134A as soon as i lowered the controller the condensing unit kicked on.

[passandscore]

Sound like you do not have a headmaster control and you needed to lower the cut-in set point on the low pressure side of the dual pressure control because the off cycle migration of refrigerant to the condenser caused the low pressure control to cut-out and it was not able to reach the old cut-in point so the system remained off. Once the cold weather passes I recommend changing the cut-in set point back.

[FEISTY]

I realize this question is over a month old but any follow-up information may help others who pull up the thread. My experience with this issue usually comes down to ...outdoor condensers are either equipped with a headmaster control or a condenser fan control. Don't confuse the high side portion of a dual pressure control with a fan control. An example would be a unit using R22 *****. The fan control would be set at 225psi with a differential setpoint of 45psi. The fan will run in cold weather when highside pressure reaches 225psi. It will cut out when pressure drops to 180psi. When pressure increases to 225psi the fan will again cycle on ...and so forth. I prefer using a headmaster unit which usually comes installed from factory on outdoor designed condensers. You need to make sure you don't set the dual control highside scale as a fan control. It is designed for high pressure safety protection only. Chicago winters provide good cold weather lessons !!

[Coorsman777]

Headmaster systems are designed to have the condenser fan run 100% of the time. This requires the system to be properly charged. You can fool the system for awhile by cycling the fan but usually the condensers on these units are not floating tube so the cycling of the fan will cause leaks due to the frequent expansion and contraction from the temperature variation.

As for the system not starting in cold ambient conditions but a heater on the receiver with a pressure control to control the heater. This will cure the problem of the unit not starting when it is cold and you will not have to seasonally adjust the low pressure control.