Heat pump tumble dryer regas

[notallbad]

Just wondering if anyone has successfully attempted a re-gas on a heat pump tumble dryer.

The dryer currently in question runs on R134a.
The dryer has been completely stripped down/cleaned/tested and re-assembled however there is no heating/cooling effect so working on the assumption it requires re-gassing. Of course, its likely theres a leak which would require soldering or even the possibility that the compressor has an internal fault even though it is running.

I was thinking of getting a car aircon regas kit or probably easier but slightly dearer an hvac kit from ebay and clamp valves that pierces the pipe for the connections on the low/high pressure sides so theres no need for any gas torch soldering.

I'm not sure why it wouldnt be necessary to vacuum the system on a car before filling (perhaps it is) but quite sure it would be necessary on the dryer so a car regas kit may not be suitable.

Grateful for any advice.

Thanks.

[Topcat]

Re: Heat pump tumble dryer regas

I never even knew there was such a thing!!!

If it's out of gas, there's a leak somewhere. If it does have charge, I'd say the internal values are malfunctioning if the compressor is actually running.....which is what my limited experience would lead me to believe. If low on refrigerant, a pressure switch on the low pressure side will open, stopping the compressor from coming in.

[sam_sam_sam]

Re: Heat pump tumble dryer regas

notallbad

I am adding to what TopCat said above

First of all if the system has very low Freon pressure in the system it would need to be purged and vacuum out for at a minimum for 30 minutes or until you have at 29 inches of vacuum on the gauge

The reason why you have to vacuum out the system is remove all non condensable and moisture out of the system also 134A is blend refrigerant and if it leaks the majority of the Freon out then the system pressures will be off and not work properly because of it if you just try to recharge the Freon in the system

Freon 134A without add oil is the normal Freon and can be used in any device the ones that say oil is add in mostly use for automotive air conditioning and the only time you need the Freon with oil is if your compressor is noisy in automotive setting otherwise use the Freon with out the oil because you can have to much oil in a system and this is not a good thing either

Please post a picture of the device in question I might be able to help you with it

[notallbad]

Re: Heat pump tumble dryer regas

thanks for the info/advice

its a learning curve for me

Its very likely that if there is a leak it will be in the evaporator coil section I guess, probably due to lack of maintenance the evaporator probably froze up and split a pipe. But as these are probably knocked up quickly could also be a weak point somewhere on one of the solder joints, but then the dryer is 4 years old so less likely to be the latter.

[CapLeaker]

Re: Heat pump tumble dryer regas

Hmm... could be actually quite a few things why this isn't working besides gas.

[sam_sam_sam]

Re: Heat pump tumble dryer regas

First dose the compressor run (if so drop down to the next line)
Second dose small diameter tube on top of the compressor get warm or if hot possible gas leak or restricted capillary tube ( which could be the metering device )

If you do not hear the compressor running dose the temperature/current overload is it good
check with multi meter for continuity if you do have continuity do you have it on all three pins on the compressor ( also check the run capacitor for the compressor as well for UF value very important thing to know if the compressor is humming when trying to start )

Please check and make sure check to see weather or not you have pressure switches ( if so continue to read this section —> ) the pressure switches will be either on the condenser or evaporator side of the system these are screw on type with two wires the majority of the time if there is check the continuity on these pressures switches ( if there are no pressure switches skip this part )

If all of these items are checked and still no compressor running and no humming is the fans running if not check the door switch or timer for continuity for these items in there running potions dose the drum rotates if not are the breakers tripped or a fuse blown

Also check for temperature sensor switches for continuity as well because this could cause the compressor not to run as well

Very unlikely that if the evaporator coil froze up that you would split the coil or spring a leak however if you had a restriction on the high side either because of a plugged filter dryer or metering device failure it possible but not very likely unless the coil is in very bad condition ( or just plain quality issues ) more often than not it is from bad brazing joints not done correctly is more often the cause for a leak problem

Take more pictures of the brazing joints and let see if this is a possibility or not

One note the picture of the compressor terminals and over load was a very good and important picture for me to look at

What is the item that I circled in blue is it a temperature sensor switch or does it have a tube on the device I can not tell from the angle at which the picture was taken to know what exactly is this device

I hope this helps you figure out what is wrong with your dryer

[notallbad]

Re: Heat pump tumble dryer regas

Thanks

There are no metering/pressure switches only an ntc temperature sensor (circled in blue which reads 25kohms at room temperature), on the high side which does get warm but might only be from conduction through the pipes from heat generated from the compressor.

The overload switch located on top of the compressor is good, continuity when cold. The compressor coils have low resistance between run/common (16ohm) and start/common(14ohm).
The 12uF start cap is about 9.5uF but have connected another in parallel to get around 15uF just to ensure the compressor is getting enough power at start up.

The compessor does run and is relatively quiet. Also the fan does cut in after some time.

[notallbad]

Re: Heat pump tumble dryer regas

Photos of joints currently exposed. Shall get photos of evaporator/condenser too.

[stj]

Re: Heat pump tumble dryer regas

you wont get freon anymore, that stuff is worth more than heroin since it was banned.

[notallbad]

Re: Heat pump tumble dryer regas

Evaporator and condenser photos, without removing completely its not easily accessible to take decent photos really.

[notallbad]

Re: Heat pump tumble dryer regas

Photo of underside of the cover in case its of interest.

[notallbad]

Re: Heat pump tumble dryer regas

couple more photos, looks crimped rather than soldered

[sam_sam_sam]

Re: Heat pump tumble dryer regas

Photo of underside of the cover in case its of interest.

This is one big reason why you are having issues with this dryer going by the pictures above in post #11

You definitely need to clean this very badly but I caution you about how to clean it properly you need get a fin comb and gently clean the coils with it but make sure that you have the right one other wise you will damage the coil and it will take a lot of time to straighten out the fins you also need to use an alkaline coil cleaner not the the acid type ones you need to get the heavy stuff off of the coil first before you any else

Now you can try to clean the majority of it off with compressed air however make sure that you go from the other side of the coil so you do not trap all this lint in side the coil also be careful about how much air pressure you use now you might be tempted to use a pressure washer you could but do not get to close the fins because you will bend them all closed ( please note that you could use an air gun with a rubber tip if do it this way make sure that only up and down the coil not side by side moment because you will close all the fins that way too )

When you think that you have the coil ( clean ) take a flashlight and shine it through the coil and see if you can see light coming through the coil if can see it clearly then you probably have it cleaned it enough for government work standards to really get it clean you would need an alkaline coil cleaner mix that 50% cleaner 50 % water and when it starts foaming add more water ( not to much because you want to keep foaming so it pushes out the lint from inside of the coil ) to it if you see smoke coming out of the coil you need to add more water to it

I hope this helps you and you understand what I have here

[sam_sam_sam]

Re: Heat pump tumble dryer regas

Evaporator and condenser photos, without removing completely its not easily accessible to take decent photos really.

This coil looks pretty good not much need to be done to this one

[notallbad]

Re: Heat pump tumble dryer regas

Pictures are after it was cleaned, fuff removed but there was not much if any at all either on the coils or on the front filter though its possible it had already been cleaned before I obtained it. Previous owner said it didnt work.

The front coil (I think is the evaporator) does look dirty/discoloured but no fluff build up. Does it need cleaning still?

[sam_sam_sam]

Re: Heat pump tumble dryer regas

It might if it still does not work correctly

What does it do now that it is cleaner than it was before you started
What is the issue now with it does the evaporator get cool or cold does the condenser get warm or hot

[notallbad]

Re: Heat pump tumble dryer regas

With just the compressor running standalone for around 25 mins the compressor itself gets hot (60/70 degrees C, the pipes tracing from the compressor all rise in temperature by around 4degrees centigrade although somewhat hotter nearer to the compressor. Started at 19degrees and rised to about 23degrees. This is at the evaporator and condenser too.

So to be clear, this is with it running without any air flow across the evaporator/condenser.


Temperature readings taken using an infrared thermometer reader.

Photos show the condition of the machine before any testing or this thread was started so hasnt been cleaned any further.

[notallbad]

Re: Heat pump tumble dryer regas

Cleaned up the evaporator coil, although there wasnt any fluff caught up in the fins the pipes did look somewhat dirty which did not want to simply wash off with water or steam so used a diluted solution of commercial oven cleaner which now makes it look much much better.

Not had chance to test yet, waiting for the oil/refrigerant to settle after having it on its sides and upside down.

I'm not expecting this to make any difference but wanted to experiment to see how best to clean it, what with and what the finished result would look like. Obviously its not possible to scrub anything due to restricted access so need something that will remove it by soaking and then rinsing.

The results can be seen in the photo compared to the before photo in post #10.

[notallbad]

Re: Heat pump tumble dryer regas

Had it running for 40 mins and still neither evaporator or condenser get hot or cold.

If I were to get a manifold gauge kit and connect to high and low sides would the pressure readings with it not running and running at least give me an idea of 1)whether there is refrigerant in the system 2) if there is enough refrigerant and 3) determine if the compressor/capillary is faulty?

thanks

[sam_sam_sam]

Re: Heat pump tumble dryer regas

Where you live I do not know if you have access to R134A set of gauges that are for automotive style or refrigerator type gauges would be better if you can buy them here in this country you have to have a journeyman license to be able to buy now the automobile type gauges you buy at Harbor Freight and place like that

There pliers that have a fitting that makes a very small hole in the tubing that allows you to put Freon in the system you really need two of them to correctly or braze a fitting that has a valve that allows you access when you need to check the system pressure

The system pressure is going to be the same as a spilt system air conditioning the setup is the same as a dehumidifier system it nothing out of the ordinary

Oh by the way the coils look very clean now I hope that you rinse it very well with plenty of plan water

What is the temperature of air coming out of the coils when the fan running and what is room temperature when you are running this test