What should the suction and high side pressure be for a r410 unit when the outside temp is 90 degrees

You turn system on to cool setting and run temp down until outside unit comes on. Then you connect your suction side of your gauges to the suction side of your outdoor unit. Next you connect the liquid(high)side of your gauges to the liquid line on your outside unit(the little copper line). Connect the middle hose of your gauges to the 410a drum of refrigerant. Before opening the suction or low pressure side of the gauges you need to turn the drum upside down and turn drum of 410a on. Then you need a temp reading meter and clamp to read the temp of your liquid line(small line). While charging you want to make sure to release refrigerant slowly. The unit should call for a specified subcooling on unit plate. 7 to 10 degrees. You take the liquid line temp and subtract it from saturation temp on the high side of your gauges.(it'll be the pink numbers on the right side of your gauge.

It sounds like you are low on charge. I think you have a thermostatic expansion valve and you need to check the subcooling, you should have 12 to 15 degrees at 95. At 95 degrees your head should be about 280# for a 12 or 13 SEER unit or higher depending on the effeciency. At 78 to 80 degrees indoor depending on the humidity, that is normal. The valve will open to try to fully feed your indoor coil and it sounds like your head pressure is to low to force enough refrigerant thru the coil.

90 psi is very high for R22....low for R410 refrigerant. If leaking by the head pressure and suction pressure will be close to to the same reading

Where are you connecting the gauges? It sounds like you have both gages on the high pressure side. You can't hook the suction gauge to the Big line on a heatpump because that is high pressure in the heating mode. There should be another tap that says low side or low pressure, that's where you hook the suction gauge. As for adding more refrigerant, I wouldn't do that until I measure the subcooling.
If you charge it in heating unless you weigh it in you want about 10° to 15° subcooling. Then this summer you need to check the subcooling at about 95° outdoor ambient then charge it to about 10° to 15° subcooling in the cooling mode and that should be the correct charge.

It is very hard to charge a heat pump in the heating mode. The pressures are low. It also depends on the outside ambient temp. If you can turn to cooling if inside temp is above 70 degrees. Take a piece of plastic and block condensor till you get your head pressure to about 235. Not discharge temp but liquid pressure near service valve. You do not have a TXV inside I believe. Get your suction pressure up a little more It is not to low on gas. If you have temp meter attatch a lead to suction line. Temo\p should be about 10 to 14 degrees difference Between suction temp and Temp on your suction gauge. If you need a charging chart I can fax you one. Rus

90 psi suction too high possible bad valves or non condensablies in the system (AIR) what is the head pressure and what type of freon r-22 410-A? your unit is never shutting off watch out for that electric bill. and did you take apart the condenser and clean it? Tom

If it is very hot in the house the suction will be high but not that high. If you have a 13 seer inside and a 10 seer outside your suction can be that high if you don't lower fan speed. Does your unit coll ok. Another reason if it is not cooling well is bad valve in compressor but the compressor would going out on internal overload because of getting to hot. If you have TXV metering device it could be stuck open. Check sub cooling. Put a thermometer on the 3/8 line and measure the difference between that temp and the guage temp. Look at your pressure and the temp reading is nest to the pressure. The difference should be between 12 and 16 degrees. Measure Large line temp for superheat difference should be between. 12 and 16 degrees. Feed back please

I have to know what the outside temp is and I also need to know the seer of the unit. It would also help to know what the indoor temp is as well. Generally your suction pressure or what you are referring to as the indoor temp will be about the same. Let's say your indoor temp is 75, then your suction pressure should be around 75psi as well. Based on the suction pressure you just gave me, I would bet that the temp is not 38 degrees. With the suction at 38 and a low head or high side, you may be low on refrigerant. 110 is a little low but again, this depends on the seer rating of the unit. A higher seer will have a lower head.

Before you start checking pressures, you need to make sure that the unit is clean inside and out. You also need to know what the ambient temp is outside so you know what the pressures should read. Without this information, your info is useless to me. You need to know what your saturation temp is to determine if the head pressure is too high or too low. If the outside unit is dirty, you will have a high head pressure and low suction pressure. If the inside is dirty, you will have a high suction and a normal to low head. My advice to you is to clean first and then start checking temps and pressures. Otherwise you are spinning your wheels.