Thermal Relief Please


Aug 28, 2019
Real Name
Steven Schafer
My new upgraded thermal relief valve for my SS 370SS is coming today. It's possible that the hose that comes in the kit will not fit to the port in box where I would like to place it. I need to order a teflon lined ss line. Does anybody know the pressure that comes out at the thermal relief? If I wanted to do something questionable like put a valve that line and run it two ways---one to the fresh water tank so when I start out in the morning and have lots of water in the tank I might divert one line back to the fresh water tank and the other which would be a constant would go back to the hot water box. As the day moves on and water runs lower I might flip the lever on hose diverting the water to the waste tank. It's seems like the best of both worlds allowing me to avoid a situation where I superheat the fresh water. I read that the cat pump is good to 190 but I don't want to find out. Seem like 190 out today. Or not? But if it's high pressure I'm afraid I might blow apart the valve.


Well-Known Member
Sep 17, 2009
Real Name
Arm Ben
Business Location
United States
That system was designed to never over heat which explains the dumpless to waste tank design. Before you drill into the waste tank and possible weaken it, Id talk to Saphire.

I could be wrong but I think the fresh water from garden bib/spigot goes into the thermal well first, it gets pre heated then into the pump the pump them runs it through the thermal well again but through the heat exchangers then through pressue regulator.

There is a vacuum operated valve that controls the heat concentration from exhaust and blower motor that is responsible for regulating the heat.

Always maintain that valve!! loosen the vacuum hoses . 1 first spray some wd40 put it back, tighten and repeat with the other lines going to it.
slide the large pinto and lube with anti-seize ( I use the copper version) found at Auto zone or Orielly

Dont foget to change the blower oil.
the best way to do that is to remove top cap and use a oil vacuum extractor or a mighty vacuum pump or a large syringe and collect and measure how much you are removing and refill with the same amount of volume. You must use the correct blower oil its from the MFG has a DX on bottle.

The water pump needs oil change too but you must use 30w ND (NON DETERGENT) oil
NAPA has it so far it is not found at O'reillys or auto zone or Ace.
STP also makes 30ND

when replacing the spark plugs apply some silver (aluminum) Anti seize on the threads to protect the heads.

and do clean out the filters and orifice

Lastly youll need to also adjust the lag of the belts. This part needs to be done precisely and on a level surface.

unfortunately you might get a motor oil leak just above the oil filter, since they do not use a gasket instead the use FIPG or some black RTV forma gasket in which fails because of vibration. if this ever happens pour a uv dye leak detector and run the engine anywhere from 5-10 minutes if its a sever leak itll show up under uv light fast if not you might need to do a few hours of running to see the leak
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Aug 28, 2019
Real Name
Steven Schafer
I was laughing at myself today because I've gone from intimidated by the complexity of the machine to exploring it's every detail. It was a great buy but I don't know it's history. It had 84 hours on it but sat for a year or so in North Carolina. The truck and equipment was spotless. Today I decided it's time for me to give it a complete once over myself. I had to order a new upgraded thermal relief valve that I should have order when I bought the rig but so be it.
--Today, I pulled the safety wall between the driver and the cargo area. I just couldn't get to the unit, it was a bad design.
--I pulled the chemical rack out of the van (Chevy Express) because I have all these chemicals but no room for my bonzer, rotovac let alone a regular vacuum. I figure I don't always need to be traveling with wool carpet shampoo. If I need it, I'll pull it off the shelf in my mini storage.
--I drained the engine oil today
--I hooked a piece of flat blue pool hose drain line to the discharge so I don't have to use my hose. It's seems to take too long to disconnect a hose I'd rather be reeling up and get it dirty and then have to down wash it so I figured a simple plumbers clamp and some blue pool backwash drain hose would fix the problem.
----Tomorrows list
--Clean engine air filter
--check spark plug but I'd bet it's spotless
--check the inline fuel filter
--check batter water
--put the copper anti seize on the diverter valve
to the bimba.
--remove hoses and spray wd40 into the bimba.
-----The O-ring in Chemical Check Valve or Outlet filter was cracked and water was spraying out. I actually bought hi-temp silicone orings and they should be in tomorrows Amazon. I will wash the screen and change the cracked o-ring and high temp lube them both before putting them back in.
--Eat Lunch
----Then I will clean the by pass manifold orifice and screen and lube with high temp lube.
---next I will give the vac inlet filter a good clean and lube the threads.....I am pulling the basket because I am going to drill a hole in the top lid so I can run a 4 to the door layout. Actually it will be a 4 to the ground where they go onto my Wander Silver Bullet 2 in 1 out inline filter.
-----To do this I will put a couple of j-don flash cuffs on the silver bullet on both ends as well as the lines from the waste tank to the silver bullet. I'm really trying to prevent any air loss.
---I have to wait for Friday until it arrives but I ordered Aeon pd xd and will replace the vacuum pump oil
---Same deal on the Cat water pump, I will change it on Friday.
---I had some water (a little) squirting out of the Chemical pump. I think this is a minor as needing (coming Friday) to lube the edges replace the diaphragm
----need to order a glide for my wand and that should do it...
I think after this I should have a rig that is capable of cleaning anything the world throws at it.
------thank you for you guidance.