Question: Hello,
I have a Mytee HP60 Sypder that's about 6 or more years old (I bought it used so I'm not sure how old it really is), but it needs a new Safety Pressure Relief Valve, I'm sure this is the one:
Mytee 175 psi Safety Pressure Relief Valve 1 4 , B124, Regulators & Unloaders, Parts & Accessories, by Mytee,  Mytee 175 psi Safety Pressure Relief Valve 1 4 Water flow direction is from Male pipe to femail pipe. Both connections are 1 4 n...

But what I was wondering was I looked at the Mytee schematics and parts list on the Mytee website and see that the newer Sypder HP60 machines done use a pressure relief valve, can you tell me why this is? How do they get away without using a pressure relief valve on machines that have a heater?
Any info would be appreciated.

Answer: That is the correct part. I will tell you that both Mytee and Sandia Plastic have recently tried removing this safety feature and it has not been without problems. The heat cores are supposedly tested to 1500 psi but I know of several that have broken that do not have the relief valve installed. When you have heaters that go over 212 degree F they produce steam and steam expands aggressively over the size of water. A 120 psi machine easily will produce over 1000 psi and break these heaters. I would highly recommend you re-install you safety pressure valve.

Mytee HP60
Mytee HP60 Spyder - 1 3 Vacs - 100psi - 1200 Watt Heater 230 volts for International Use , HP60-230v, Auto Detail Machines and Extractors, Auto Detailing & Car Wash , by Mytee,         HP60 Spyder 230 volts      ...