Air Drier unable to dry air

[bert]

I've got an old'ish Boge air drier that doesn't seem to be able to dry air. Today I turned it upside down and used brake cleaner to get any left over oil/water out and made sure the drain is clear and dry.

The fan comes on straight away and the cooling system seems to be getting cold

But it can't get the air moisture down. At the moment it's disconnected from the compressor and is at 96%humidity.

Is there anything I can do or as its so old is it best to buy a new one.

Thanks
Darren

 

[Shox Dr]

I'd try and repair it, sounds like an old unit so should be doable. That or sit down with a stif drink before looking at new ones

 

[mtt.tr]

I'm assuming this is a refrigerated dryer?

Does the AC compressor run?
Are the pipes changing temp?
Does the condenser fan blow?

Gas is the most common issue
Aswell as over pressure due to condenser fans not working

Inside you should have black pressure switch that can be reset


Post the model no.

 

[bert]

It's a boge DB70 machine, 59000 hours on it so it's had a fair bit of use.

I'm not sure about the condenser but the fan is running all of the time.

There is a part that gets very cold to the point it can ice up but not sure what it is.

I can take pics on Monday of the insides

 

[angellonewolf]

is there a fan and condenser unit with ali fins ?

our ice maker mechine stoped working at work all it took was a clean out of the fins and fans as they whetre not getting rid of the heat as fast as needed so stoped working worth a look ?

 

[jsf55]

Do these have a massive corrugated filter in them ? our's used too block up just after all the pollen stuff was released

 

[bert]

Pics of the machine, turned it on this morning and it's still in the 80% humidity after being open all weekend.

The silvery disc with the wires going in and out gets really cold.

The fan is on all the time

 

[knighty]

silver disk thing is the expansion valve, which meters the liquid refrigerant through into the evaporator (cold bit)

if that's getting cold quick it's a problem, normally it means it's being fed a gas/liquid mix

which normally means not enough refrigerant in the system, but can't tell 100% without putting some gauges on it

the radiator with the fan on it, is it good and clean? - the pipes in and out of it, in (at the top) should be hot, out should be room temperature

 

[bert]

I've turned it on for 10mins, the humidity is up at 92%. There is no air running through it at the moment so inlet, outlet and drain are open.

The expansion valve is down to 12 degrees.

The radiator is clean ish, I've blown it through this morning so no dust etc

Pipe at the top is 26degrees and the pipe at the bottom is 21degrees.

It has some temperature controls any idea what they should be set to?

At the moment it's set at minus 10 with a difference of 4 degrees

 

[bert]

 

[bert]

After 30 mins the expansion valve is down to 3 degrees and frosting up.

The top pipe on the rad is 31degrees and the bottom is 21degrees.

Does it look like it doesn't have enough refrigerant in it?

 

[knighty]

temperature / pressure controls etc. shouldn't need touching unless they need replacing

they'll only control the compressor/fans on/off, so if it's running and getting cold they're probably ok

try running some air through it, maybe the humidity sensor is too far away from the condenser (cold bit)

also... 952% humidity is really high... maybe it's just a duff humidity sensor?

run a bit of air through it to check?

tbh I'm not sure how you'd check how dry the air is coming out

check for water coming out of the dryer drain?

 

[bert]

Connected it all up today and gave it a really good test.

No water in the traps after 4 to 5 hours of running and nothing much coming out of the drain solonoid.

Took the drain cap off and it had quite a lot of water in the machine.

Looks like the solonoid isn't getting rid of the water but let's air out when it opens.

So I think it's drying air but holding the moisture in.

 

[knighty]

that's a pretty good result really, easier to fix a water drain than a refrigeration system?

if it starts to be a pain just get one of those ebay auto drain solonoids?

 

[bert]

I took the drain solonoid off and it had a 1/2" unf thread.

Blowing air through the machine it's holding a lot of water so I need to get the auto drain sorted.

If I buy a solonoid with 1/2" thread and a 230v solonoid that should work just fine.

The machine itself controls the solonoid signal and under normal conditions fires every 20mins, at the moment its trying g to fire every 1 min as the humidity is so high.

I found this which I think will be OK but not 100% sure

1/4" 3/8" 1/2" 3/4" 1" 11/4" 11/2" 2" Solenoid Valve 12/24/240V Normally Closed | eBay

Find many great new & used options and get the best deals for 1/4" 3/8" 1/2" 3/4" 1" 11/4" 11/2" 2" Solenoid Valve 12/24/240V Normally Closed at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[knighty]

you could try a magnet on the solenoid to see if that gets it to move?

no screws on it take the top off and wiggle it free? they're pretty simple things

those ebay ones look fine to me tho

 

[bert]

I've been using a magnet to open the solenoid, it's a bit hit and miss so needs replacing anyway and should let the machine sort it's life out on its own.

 

[bert]

Ordered a new solenoid but the magnet trick is not working today so removed the solenoid and added an air fitting and blow gun to let the air/water out

 

[bert]

 

[mtt.tr]

Have you also drained your receiver?


These solenoid valves can be had for not a lot of money online.
be worth cleaning the coils and the compressor radiator. Also drain the outlet filters if you have them, might need new float valves

i've seen these well past 100k hours not bad machines just not an HPC just keep on top of maintenance