Hotbox Help

Hello everyone, it's Jesse from Spring, Texas. I was wondering is anyone would be able to help point me in the right direction. I purchased a hotbox a while back from a guy who no longer needed it. The only problem was he had a new control box that had to be put on, being that his brother hooked up the original box incorrectly. He said he used it for about a year with no problems. Anywho, I took it to a gentleman who said he could hook up the new box and check the coils and fuel filter and everything. I recently got it back. He replaced a few thing on it, mounted the control box with a new thermostat, and said it was running fine. I got home, hooked it up to my 12v battery and it turned on, but produced no heat. Also, when I hooked up my pressure washer, I got no water coming from the hose. All the water comes out of the heat release valve(or something of that nature). I have it filled up with deisel, I'm not quite sure what to do. It is a USA Pressure Systems hotbox. I can probably take it to someone around here again, I just want to be sure it's not something I can do, or maybe I am doing something wrong.

Thanks in advance for any info anyone is willing to share.

Post pictures of the plumbing and wiring, probably something simple.

There are a lot of great experts here, pictures of everything might point out a problem.

will do, thank you so much, also, I hope I posted this in the right forum.

It won't fire unless there's water flowing through it. So, if you can't get water through, it's doing what it's supposed to. Check your nozzle to make sure it's not clogged. If the heater has been sitting awhile, there may be crud in the system, which would stop up the nozzle.

Side note: Any time you buy a new hot box or hot pressure washer, or if has been sitting for awhile, or has been welded on, run water through without a hose and gun for a minute or two to flush the coil.

you bought it in leander Tx didnt you? thats the problem.

El Flojo said:

you bought it in leander Tx didnt you? thats the problem.

Click to expand...

I actually bought it from a gentlemen here close to where I live, I'm posting some pics today.

I'm not sure if I uploaded right. Here are some pics. When I hook up the pressure washer to the hotbox, the water shoots out where the little clear tube is. I'm not sure if I am hooking up the pressure washer wrong or not. I don;t get any whater coming out of my hose, it all comes out of the clear tube. I'm not sure exaclty how to explain it, I apologize.

http://s94.photobucket.com/albums/l104/gaisee/Hotbox/ if the pic doesn;t come up, this is the link. Sorry.

Okay, let's start picking this thing apart. First, that's a thermal relief valve with the tube on it. It doesn't belong there. It goes on the inlet side of the pump to keep the bypass water from overheating. Yours is probably blown now by exposing it to high pressure. Remove it and plug the hole.

Next, there's a pressure switch on the inlet of the heater. It needs to be a flow switch. A trapped pressure unloader will keep a pressure switch engaged, and the burner will stay on...can you say BOOM!? You need a flow switch that is made for horizontal mounting, ST6 or MV60.

Get those changed out and it might just work.

PS The inlet is on the bottom, the outlet is on the top.

thanks Russ, I'll try and see if I can find someone around here that can do this for me.