About refrigerant type compressed air dryers

[rcx132]

Picked this up on eBay, it's a fairly small compressed air dryer. I've been using desiccant upto now but it's getting costly, supplier has said that new environmental regs in China are pushing the price up.

I plugged it in yesterday and the light comes on but that's all. The fan behind the radiator does not turn or anything. Does it only kick in when it detects compressed air?

Any way of knowing if it's worn out? I thought connect some coloured desiccant, so if it's letting moisture through then the desiccant would change colour.

Also, how effective are these dryers? I just can't imagine that they can cool the air enough in the few seconds in which it passed through.

 

[addjunkie]

Take the cover off lets see whats inside

 

[Ed ke6bnl]

they are rated for a certain cfm so if you stay within that range they will give you dry air. I would think it should come on with out being on your compressor. I believe the small one I have will just fire up.

 

[rcx132]

The owners son phoned me as he got the dryer from work, he services them. He said it only kicks in once it detects the air is above a temperature. He promises it was tested. Will have to plumb it in properly then and see what happens after warm air starts going through it.

 

[carbon]

The one I have starts as soon as it’s turned on , then turns off when cold. Any increase in temperature turns it back on again.