There was a series of problems getting the charge correct. In the heat mode the system would lockout on high pressure after 2-5 min. of operation. The final conclusion was to run the system on a low charge. It produced heat but it ran at very long intervals for small gains in heat.

Fast-forward to summer 2009 and we now had a system that ran a long time to try to cool. Having forgot about the low charge given to the system over winter, I looked to troubleshoot for simple problems. I found the evap fins covered with a blanket of dog hair. I cleaned the evap and the HVAC tech came out and "corrected" the charge, by raising the pressures. The system blew much cooler and cycled less frequently.

Now we are getting cold nights and I am flashing back to last year where the tech left me with an undercharge to avoid the high-pressure lockout. The system is locking out at 2-5 min of runtime.

To rule out airflow across the evap I opened up the cover and ran the system, allowing air to come out unrestricted after the evap. The air handler is an up flow design with an A shaped coil. As the system ran I could feel heat coming in to the coil on the line, I could feel heat on the top 1/3 oh the coil. The bottom 2/3 of the coil was room temp at best. The line returning to the heat pump was also cool.

I own an automotive repair business and am very familiar with A/C in cars. At the time of the conversion from r22 to r410 I asked the installer about the compatibility of the two refrigerants as well as their oils. They said that the flushing process would rid the system of the possibility cross contamination. I don't remember anything more being done than blowing the line set with nitrogen, but I can't say that a flush chemical was not used.

Is it possible that the oils did mix and turned to sludge in the evap? Without buying a 410 gauge set, what can I do to further determine what is going on before I call the HVAC contractor back out? Is there a kit that can sample the freon and determine if oils are mixed?

The evap is labeled for r22 or r410 so that is why it was not changed. The cover is still off the EVAP so I could perform temp tests if that would help.

Thank you, Bryan.

We have reused many linesets, at first just blew out, then started using a flush solution. No problems yet, knock on wood, and a lot of installers do the same.

Could be a bad TXV, required a considerable overcharge just to work in cooling mode, then in heating mode have to reduce that overcharge.

The txv has a 45ZGA on the top and CBBIZE-6, Y1158, 96, and 20308 stamped in the side of it. The sensing bulb is installed on a vertical suction line leaving the EVAP housing. The tube from the bulb is pointing downwards.

Also, I just read on a sticker inside the access door to the condenser: "Do not use with capillary style evaporator." My EVAP has six small tubes that join at the txv. Is this a capillary style EVAP?

EVAP: Unitary/York Model G2FD048H21G "Design Pressure 500psig"
Heat pump: York YZH04811B "Design pressure High side 650psig; Low side 350psig"

Is the "Design pressure" mismatch a problem?

Thanks Again.

Next all your refrigerant needs to be removed and then new 410A put back in. Once you lose 30% of 410A you lose the ratio of the 410A blend.
But they will need to also do another deep vacuum and put in another filter drier.

I would find a new contractor and then at least replace the evaporator coil or better replacing the air handler with 410A air handler. Also get a good filter system like a aprilaire flex filter because you have dogs.
Find a new A/C contractor, you are going to kill your new outside condenser with that setup.

The system was installed new in November of 2005. The EVAP was 3 years old when the outdoor unit was replaced in 2008. The change to a heat pump was because we are on propane and wanted to go electric. Our house came with solar electric when we bought it in 2005.

The system was not a TXV R22 style. It used an orifice. When converted to R410A the described TXV was installed. Is that valve correct for a 4ton heat pump?

The sticker on the EVAP says for "R22 or R410A" but I am still concerned about the capillary tube warning on the heat pump. When a EVAP has 6 small tubes going to the TXV is it a capillary design?

Is the TXV bulb installed correctly? It is on a vertical suction line with it's tube pointing downwards.

I agree with going to a new contractor, but I need to be sure the new install/repair is done correctly so this information has been very helpful. Thanks.

The dog hair sitituation was due to a poor fit of the filter in the air handler. I have corrected that by installing filters in the returns at the registers. When I opened the cover up to the evap the second time it was clean as could be.

The air handler is Weatherking 90% and has worked well with propane. It was installed in 2005 at the same time as the rest of the system. I hope to not have to replace it.

Thank you.

Indoor coil is a YORK that was installed with the system in 2005. The label says "For R22 or R410A".

EVAP: Unitary/York Model G2FD048H21G "Design Pressure 500psig"

Heat pump: York YZH04811B "Design pressure High side 650psig; Low side 350psig"

EVAPORATOR...

I read, on a sticker, inside the access door to the condenser: "Do not use with capillary style evaporator."

My EVAP has six small tubes that join at the txv.

EVAP: Unitary/York Model G2FD048H21G "Design Pressure 500psig"

1.)Is this a capillary style EVAP?

DESIGN PRESSURE...

2.)Is the "Design pressure" mismatch a problem?

EVAP: Unitary/York Model G2FD048H21G "Design Pressure 500psig"
Heat pump: York YZH04811B "Design pressure High side 650psig; Low side 350psig"

TXV...

When converted to R410A the described TXV was installed.

3.)Is that valve correct for a 4ton heat pump?

The txv has a 45ZGA on the top and CBBIZE-6, Y1158, 96, and 20308 stamped in the side of it.

MORE TXV...

4.)Is the TXV bulb installed correctly?

It is on a vertical suction line with it's tube pointing downwards.

RECAP...

1.)Is this a capillary style EVAP?
2.)Is the "Design pressure" mismatch a problem?
3.)Is that valve correct for a 4ton heat pump?
4.)Is the TXV bulb installed correctly?

Again I thank everyone for their input. It is always appreciated. Bryan.

So right now I would say you need to determine if the existing txv is the correct size. You can probably search online for a sporlan catalog and see what the capacity listing is.

A cap tube metering device was used for many years before txv's became standard. Since you have a txv you don't have to worry about the warning sticker.

I was hoping to make lemonaid out of a lemon of a system. I will find a new contractor to match the indoor unit to the outdoor heat pump.

How can I determine if damage has already happened to the heat pump?

Thanks again.

Honestly it sounds like to me the guy forgot to take the bullet orifice out before he installed the TXV.

Hope this helps

But heres some info that might help:

no its not a cap tube system if it had an orfice originally. and yes thats normal to have 6 little tubes coming out of the txv, that just distributes the refrigerant evenly across the evap.

sounds like the txv. either installed backwards (metering twice) or valve stuck. Most TXV's you can open by unsrcewing the cap on the bottom then turning the adjustment screw counter-clockwise till it stops. make sure you count the number of rotations, so that if it does clear then you can set it back to original posision.

I will adjust the txv and see if that will clear it.

I did not see anything to identify if the valve is installed forward or backwards. What am I looking for?

Thanks, Bryan.