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Good Morning

We have been running into a lot of high velocity calls lately with these new builds. Most are not installed with a freeze stat which is has been the issues on alot.
We just replaced a unit with lennox ACX13NO24 with a MAXAIR slab Coil (2ton) with TXV and  with freeze stat. The air handler is Temp Mizer HV-71H. Since installation she has called multiple times saying it is not bring her place down to temperature. The Square footage is  1600 Square feet.
I get a 0 degrees sub cool and a super heat of 13. My pressures go wonky which i assume is because the outdoor unit is freezing up at the service valves.
It seems like the outdoor unit is freezing up by the service valves and evap coil is not freezing so it goes off on freeze stat. Ive tried tech support for MIZER and they say we are suppose to match everything. Lennox says their equipment isnt made for high veloity even though we have used it before.

Has anyone had issues with these high velocity? or have any ideas.

How many registers does the place have? I think it needs 16 for two ton AC?

Is the TXV bulb mounted properly?  What's the temperature drop temperature?

Which line is freezing outside, liquid or suction?

You may want to remove the refrigerant and pull another vacuum and recharge.

There is two seperate systems in the house. This one does the main floor and lower level. I would say it probably has 12 or so registers , havent actually counted. I can do that monday.

I have pulled the charged and re charged already.

Temperature drop was about 25. I had 43 degrees coming out of the supply.

both lines were freezing at the outdoor unit.

That temp drop seems high and the coil is too cold.  Are you able to increase the indoor airflow?  Did you try running the system with the door off the indoor unit?

Did they reuse a filter drier?  Or was it replaced?  It could be a restricted liquid line or bad TXV.  I would start with the TXV if your pressures are wonky.

nope, everything was new.. new line set, new filter drier.
i am heading back today to do some more checks. I am going to see if i can increase the fan speed but i dont think I can.

Ive called tech support and the air handler company wont help because we didnt match the evaporator coil for their air handler. we used a different manufacture with a lennox. lennox also says their units are not made for high velocity

i am going to do more checks today and maybe think about swapping the coil to the proper manufacture to match the air handler

Does anyone really know the operation of them? I Know  the CFM is lower. My fan is on high. Its condensating great. My pressures were actually good today. was 48 degrees in the supply and 65 in the return.
76 in the house. Customer says it still doesnt bring it down to temperature. Its 1600 Square feet. There is about 18 runs on the main floor and top floor. I had 52 degrees coming out of the supply at the vent on floor.
Main floor is full of hardwood.

This house is in wharf at pickering marina. Do you think it may be undersized for the area? water near by raising humidity. She says she keeps blinds  and doors/windows closed.

Is the evap coil suppose to freeze? It ran for about an hour without freezing up. Is freezing up normal or is the freeze stat only there incase it freezes up?

Supplier said I should have put in a 2.5 Ton coil to match the air handler

The freeze stat is only there to shut down the AC if the coil freezes to prevent it from freezing the water coil in the air handler.

The coil should be sized based on the size of the AC, not air handler.  The air handler may support a 2.5 ton coil but if you have a 2 ton AC there is no problem using a 2 ton coil.

if the temp drop is 17F it's cooling well.  It may be undersized if it's not keeping up on hot days.  A larger indoor coil would increase the SEER but a 2 ton AC will only give you 2 tons of cooling.

Did ice up on you though so there is something going on...

right, thats what I was thinking as well. Thanks for your help. If I come across anything else I will be sure to throw something out. Thanks!!