walk in freezer

[mastercheif602]

Got this walk in freezer that triped on high head in the middle of the day. Mind you I live in arizona and a hot day is 120 in the shade. So I hit the rest and the unit runs. Head at 400 box real hot. So I look at the sight glass and bubbles, unit is leaking cause one of the other techs but gas in it the day before. So pump it full of nitrogen and leak check.

Found the Txv leaking out adjutment stem. This would explain why the txv was frozen soild. So today I put in a new txv. The old one is a old 502 1 Ton. I get the parts guy to size me a txv based on the condensing unit. 6000 btu compressor. So I find the label on the old one and it is a one ton. So I put in a like for like, do my thing and get the unint back on line.

Now my question is If I took out a one ton txv, does this mean that my evap is at least a 1 ton.

If I put a 1/2 ton condensing unit on it will it ever keep temp. The name plate on the unit says max 0 degrees.

Am I on the right road. I will give more info you need. Kinda baked from the sun today.

Let me know. :confused:

[ateeq.baig]

Friend
you should write your question with simple way because we cannot understand your question
or cannot understand that what you want to say or ask

[mastercheif602]

ok guess I was rambling.

My question is:

If a txv is rated for one ton of cooling, Does the condenser need to be rated the same.


I have a freezer that has a 1 ton txv with a half ton condensing unit, or 6000 btu's.

Will this cause the box to take a long time to pull down in a hot enviroment.

[KenXL]

you should select TXV according to the capacity of eva, of course eva is following the capacity of the walk-in freezer. say the eva and TXV is 1RT, the condensing should be a bit more bigger than 1RT in order to get subcooling.

[Toosh]

Hi, Did the system work ok before, 2nd did you find the leak, now can you give us super heat and subcooling

Norm

[Gary]

In general, a TXV will control down to about 1/3 of its rating. With the refrigerated space warm, the TXV could open up and flow enough refrigerant for 1 ton. This could put a very heavy load on the 1/2 ton condensing unit until the refrigerated space pulls down to temperature. This will actually pull the box temp down faster... if the condensing unit can handle the overload. More likely it will kick off on high head and/or trip the compressor overload, especially given your high ambient temp.

Once the box is down to temp, if the load is less than 1/3 ton the TXV will hunt, because its orifice is too large to handle less than 1/3 ton. However, if the coil is large (1 ton), then the load will probably not drop that far and all will be well.

So... the big problem is getting the warm box down to temp.

[nike123]

ok guess I was rambling.

My question is:

If a txv is rated for one ton of cooling, Does the condenser need to be rated the same.


I have a freezer that has a 1 ton txv with a half ton condensing unit, or 6000 btu's.

Will this cause the box to take a long time to pull down in a hot enviroment.

If condensing unit is matched to compressor than I would say no. Reason is because heat load in freezer is increased with heat from air infiltration and thru the walls because of high ambient. That additional heat load is slowing your pull down time.

First you size evaporator according to heat load, then you size compressor by required refrigerant mass flow for given conditions, then you size condenser which is able to get rid of heat from evaporator plus heat from mechanical work of compressor, but in your ambient temperature. Than you size TXV according to evaporator capacity, system pressures and pressure losses at pipes and evaporator distributor.