Safety Valves
- Thread starter tomtucson
- Start date
Hotwaterwizard
Hotsy Service Tech
1) Do you recommend more than one safety valve?
Two would be Optimum One Before the Unloader and one after the unloader. Before the Flow switch and coil.
Some manufactures put one on the coil output also but you need a special one that can handle heat for this one.
2) Is a burst disk equivalent to a safety valve?
No! It is a different type of safety valve. It serves a different purpose. It is designed to burst when the temperature is too high. These prevent the coil from exploding when the heat stays on with the trigger off. There is lead inside that melts. If this one pops you have a burner problem and service is required NOW.
3) Have you ever seen an unloader fail and block flow from the pump? should there be a valve between the pump and unloader?
Yes and Yes.
There is another type that I also recommend. It is called a Thermal Relief Valve or Pump Saver. It goes on the pump inlet. It's purpose is to relieve the bypass water when it gets too hot. Most unloaders are plummed back into the head of the pump. The friction of the water circulating causes the water to heat up. When it gets up to 140 deg F dammage can occur to the packings of the pump. This will open up and let fresh water go thru the head cooling down the packings. The cause of this one popping is from leaving the pump in bypass to long. Unlike a burst disc this one will reset when the temperature is adequate and the machine is shut down and restarted.
Two would be Optimum One Before the Unloader and one after the unloader. Before the Flow switch and coil.
Some manufactures put one on the coil output also but you need a special one that can handle heat for this one.
2) Is a burst disk equivalent to a safety valve?
No! It is a different type of safety valve. It serves a different purpose. It is designed to burst when the temperature is too high. These prevent the coil from exploding when the heat stays on with the trigger off. There is lead inside that melts. If this one pops you have a burner problem and service is required NOW.
3) Have you ever seen an unloader fail and block flow from the pump? should there be a valve between the pump and unloader?
Yes and Yes.
There is another type that I also recommend. It is called a Thermal Relief Valve or Pump Saver. It goes on the pump inlet. It's purpose is to relieve the bypass water when it gets too hot. Most unloaders are plummed back into the head of the pump. The friction of the water circulating causes the water to heat up. When it gets up to 140 deg F dammage can occur to the packings of the pump. This will open up and let fresh water go thru the head cooling down the packings. The cause of this one popping is from leaving the pump in bypass to long. Unlike a burst disc this one will reset when the temperature is adequate and the machine is shut down and restarted.