fresh water dumping into waste tank

**macgyver3d3** · 09-09-2009, 11:07 PM

just bought a hydramaster maxx 470 cleaned a carpet the other day and had to dump 4 times (100gal waste tank) today i checked it out and as soon as i turn on the solution punp switch it starts dumping into waste tank. any help would be appriciated thanks

**Ara Klujian** · 09-10-2009, 12:05 AM

The Maxx 470 is not suposed to dump into the recovery tank. It has a diverter system for the exhaust that eliminates any dumping. The only thing I can think of would be your thermal valve stuck open allowing water to enter the tank.

**macgyver3d3** · 09-10-2009, 07:23 PM

i checked the thermal valve and its ok . any other suggestions ? dump solenoid? how can i check it. thanks

**wandwizard** · 09-10-2009, 08:02 PM

It sounds like the solenoid on your recovery tank. It will fill your recovery tank up quite fast if that thing goes bad. If it's like the one on my Boxxer you will have a high pressure line going from the machine to a solenoid on the recovery tank that has two wires attached to it. Here is a link to what it looks like. http://www.demaeng.com/product.php?id=87&catid=33 Under normal operation it shouldn't activate too much, but when it's stuck or bad it will open up and bypass constantly. When the thermal relief valve goes bad you can clamp off the hose that goes from the valve to the waste tank and the bypassing will stop, but you can't do anything when the high pressure solenoid goes bad, but replace it. I don't know for sure that your machine has this solenoid, but I am thinking it will have one. Here is how to check it. First get the machine running and get it pretty hot say over 200 degrees. Turn it off just for a second and remove the recovery tank lid. Turn it back on now and turn your temperature dial down below what the temperature it is saying on the temp gage and the valve should open. It should close when you raise the temperature above the temperature on the temp gage. If it's not working it will just be continuously bypassing into the waste tank. As far as I know this valve only opens to cool the machine down when you lower the temperature on the temperature control knob. It may also bypass some when the machine gets above the set temperature to cool it down to the right temp.

**Classicboss** · 09-10-2009, 08:21 PM

Originally Posted by wandwizard

It sounds like the solenoid on your recovery tank. It will fill your recovery tank up quite fast if that thing goes bad. If it's like the one on my Boxxer you will have a high pressure line going from the machine to a solenoid on the recovery tank that has two wires attached to it. Here is a link to what it looks like. http://www.demaeng.com/product.php?id=87&catid=33 Under normal operation it shouldn't activate too much, but when it's stuck or bad it will open up and bypass constantly. When the thermal relief valve goes bad you can clamp off the hose that goes from the valve to the waste tank and the bypassing will stop, but you can't do anything when the high pressure solenoid goes bad, but replace it. I don't know for sure that your machine has this solenoid, but I am thinking it will have one. Here is how to check it. First get the machine running and get it pretty hot say over 200 degrees. Turn it off just for a second and remove the recovery tank lid. Turn it back on now and turn your temperature dial down below what the temperature it is saying on the temp gage and the valve should open. It should close when you raise the temperature above the temperature on the temp gage. If it's not working it will just be continuously bypassing into the waste tank. As far as I know this valve only opens to cool the machine down when you lower the temperature on the temperature control knob. It may also bypass some when the machine gets above the set temperature to cool it down to the right temp.

My bet would be on a dump solenoid, could be defective if the machine is new. I haven't had one go bad yet... but talked to a few who have and it sounds like what theirs was doing. good luck, when you find out let us know. Thanks

**macgyver3d3** · 09-10-2009, 08:22 PM

yeah that looks like the same solenoid, and its dumping water from the minute i turn the pump on (so the machinie is cold) at that point, and dose not stop so must be that you think? thanks

**Jason Whaley** · 09-10-2009, 09:01 PM

Does that machine have a bypass valve you can open to bypass the water to the waste tank?

If so maybe its open a little or it needs replacing.

**wandwizard** · 09-10-2009, 09:38 PM

If it's dumping from the moment you turn the machine on my bet is the high pressure solenoid is stuck in the open position. I have on one occasion gotten it unstuck by doing a descale. When the water bypassed through the valve with the truck mount descaler in it the valve started working again. The other 2 or 3 times this has happened though I had to replace the solenoid and they are about $170.00 from Jondon. If your thermal relief valve is working and the machine is bypassing a lot of water then this is your problem since these are the only two things that allow water to bypass to the waste tank. Like I said, if you clamp off that hose that comes from the thermal relief valve with vice grips or something and the water stops bypassing then that is the problem. If it continues to bypass just as bad then the solenoid is the problem. I have had this problem several times before with my Boxxer and I am fairly sure your machine is set up the same way. I would call Jondon and ask for their service department. They have been very helpful to me over the years in trouble shooting problems like this one. Jondon is 1-800-400-9473

**Ara Klujian** · 09-10-2009, 10:35 PM

You guys, this unit is not suppose to have a bypass solenoid.

http://hydramaster.com/truckmounts/maxx/

ADC™ Diverter Heat Control System

The Maxx Performance Series uses an exclusive new heat system technology that controls temperature without dumping hot water into the waste tank. Coupling a thermostat to an actuator, temperature is controlled by opening and closing the stainless steel diverter valve. Solution temperature can be varied between 160° to 250°F or turned off for flood restoration work.

**wandwizard** · 09-10-2009, 11:19 PM

Originally Posted by Ara Klujian

You guys, this unit is not suppose to have a bypass solenoid.

http://hydramaster.com/truckmounts/maxx/

ADC™ Diverter Heat Control System

The Maxx Performance Series uses an exclusive new heat system technology that controls temperature without dumping hot water into the waste tank. Coupling a thermostat to an actuator, temperature is controlled by opening and closing the stainless steel diverter valve. Solution temperature can be varied between 160° to 250°F or turned off for flood restoration work.

Ara, you could be right, but then how could it be bypassing water into the waste tank from the moment he turns the machine on if the thermal relief valve is good? Jondon also told me when I bought my Boxxer that no water would be bypassed to the waste tank to control the temperature, but it does exactly that through the high pressure solenoid. I've never seen a Maxx 470 except on the show room floor, but obviously something is in fact allowing water to bypass to the recovery tank from the moment you turn it on so there has to be a valve or solenoid that is doing this don't you think? It may use something other than the high pressure solenoid I mentioned, but it has to have some part that is allowing water to bypass non-stop. Btw, Hydramaster has made quite serious mistakes in their manuals and in their descriptions and makes no effort to correct them even when you tell them about it. For example, they say in the manual and in their descriptons on the Boxxer 421 that you do not need a cold water supply hooked up when doing flood work. I called them about this and they flat out told me it was a mistake, but have they have never corrected it to my knowledge. Take a look. This is from their web site on the Boxxer 421 today and it is wrong, wrong, wrong. This is the same thing my Boxxer manual said 6 years ago. Now either the people at Hydramaster don't know what they are talking about or this is a colossal mistake that could ruin someone's truck mount.

Quote, "Smart Heat Control

If water damage restoration is part of your operation, you’ll find the standard equipment ADC™ Automatic Diverter Control a valuable feature. Unlike many units on the market, the Boxxer does not need to be connected to a water supply to do extended flood extraction work."

Hold on now, the folks at Hydramaster, who should know their own machines, told me this was a mistake and that it does need to be hooked up to cold water for extended flood extraction, but they have not made the correction to this day on their web site or in their manual. I believe if you followed the manual on this it could do serious damage to the machine.

**wandwizard** · 09-10-2009, 11:23 PM

Originally Posted by macgyver3d3

yeah that looks like the same solenoid, and its dumping water from the minute i turn the pump on (so the machinie is cold) at that point, and dose not stop so must be that you think? thanks

I just want to make sure I understand. You said it looks like the same solenoid so your machine does in fact have a high pressure solenoid on the waste tank then right?

**Ara Klujian** · 09-11-2009, 12:11 AM

Randy, you are absolutly right! Any and every heat exchanger needs cold water hookup during a flood to be on the safe side.

I know, I thought it was kind of funny when he said that looks like the solenoid. Not laughing at macgyver. Just laughing at the fact that there could be a solenoid and hydramaster says there aint one. Maybe its a used machine and the previous owner put one on?

Whaley could be right about the manual bypass! I have not seen the 470 yet or a sevice manual for it.

What Macgyver needs to do is trace the line from the tank and see what or where that line is coming from.

**macgyver3d3** · 09-11-2009, 08:50 PM

yes it dose have a hp solenoid and i checked it out seems to be opening and closing when i tested it off the machine by it self. what makes it normally open when all is working properly. maybe a sensor or somthing like that. i have all day tomorrow and will try to trace all wires and waterlines. thanks everyone i appreicate all of your help.

**Ara Klujian** · 09-11-2009, 10:01 PM

Have you descaled your truckmount lately? If not, try that.

http://www.truckmountforums.com/forums/ask-our-repairmen/7546-descaling-your-truckmount.html

**wandwizard** · 09-12-2009, 02:05 AM

Originally Posted by macgyver3d3

yes it dose have a hp solenoid and i checked it out seems to be opening and closing when i tested it off the machine by it self. what makes it normally open when all is working properly. maybe a sensor or somthing like that. i have all day tomorrow and will try to trace all wires and waterlines. thanks everyone i appreicate all of your help.

The temperature control knob on the front of the machine controls when this solenoid opens and closes. For example, when you are working and are about to shut the machine off you lower the temperature first right? What will happen when you turn that knob down is this solenoid immediately opens to bypass water into the recovery tank. Say you are doing some delicate upholstery or wool carpet and you set your dial at 170 degrees or so. Every time the machine gets a little over 170 it will open up and bypass water. I normally operate for carpet cleaning with the dial set to 250 degrees which the machine cannot really achieve so I don't bypass while working. When I do upholstery though I like to use 200 degrees so the machine has to regulate the temperature and bypass some water ever so often to keep the temp around 200. If this thing is opening and closing properly when you turn the temperature dial on the machine up and down then the only other thing that bypasses water is the thermal relief valve. The way I was told to check the thermal relief valve was to clamp off the hose that comes from the valve that goes to the waste tank and the bypassing will stop which means the thermal relief is stuck in the open position. I've had to replace several of those too in the last 7 years on my Boxxer 421. This solenoid and this valve have caused me more trouble with my machine since I've had it than anything else, but they are fairly easy to fix. You just need to make sure which one is causing the problem.

**macgyver3d3** · 09-12-2009, 08:31 PM

it was the solenoid stuck open. thanks for all the help seems to be working good now. i just bought the machine (used) and it had been sitting awhile.