Hot Water

Steven Rowlett

Steven Rowlett

Member
Hey Wiz.,When I turn the burner on without a gun attached, open hose the burner will not ignite without closing the ball valve part of the way. I use the burner to heat water this way to mix oxcylic acid. The burner works fine otherwise. I think the pressure switch is sticking without pressure being applied, any thoughts. I thought I would ask before I replace it. I always keep a spare switck, just like everything else.
 
if you dont mind

i am trying to learn as much as i can about fixing my own machine so i want to take a stab at this to see where im right or wrong. Hope you dont mind.
the pressure switch has a micro switch in it that is activated by a plunger that moves when pressure is built up or released? The switch tells the burner or fuel sel. to turn on or off?
Steve is saying this switch wont work without back pressure. The flow switch can be wired so it works on normaly open or normaly closed? This just means it's wired to turn on or off depending on the plunger act. position of the switch?
So to check the switch[the plunger activation], you could remove the 4 screws on the plastic houseing and watch it,correct?
if the switch is working with the gun attached then i would think the micro switch is OK but the plunger part my me malfunctioning [the spring is shot?] or can it be something related to the unloader? If it's a flow type,maybe the open hose is not building enuff pressure to move the plunger?
Thanks for your time and if you have time after helping STEVE please help me to understand a little more about what's right and what's wrong with my thinking on this. My closest place to get work done on my equipment is 50 miles away and im not sure i want him to work on it. He has a habbit of bypassing things and his shop is a total mess.
Landa dealer go figure.
 
There is a spring inside of the transducer that will often break. Some switches also have a lower activating pressure than others it is usually printed on the outside cover of the switch you need the lowwer activating type that usually has a weaker spring inside.
 

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The spring does not apear to be broken and it was working without the gun before. What next? The plunger apeared to have ridges on it from wear and I filed them down smooth. I have a new switch but I wanted to figure this one out before replacing it.
 
First operate the switch by hand, if it feels weak it is probalbly no good. Then use your electrical tester to check for contunuity. I have replaced the micro-switch and still had an intermittant no heat/steady heat problem. I also found the plunger was stickey. After changing the whole switch, the problem went away.

My PW has 3 wires going to the mico-switch, only 2 are used. I cut the unused wire off. This reduces the chances of my putting the wires on the wrong terminals.

Douglas Hicks
General Fire Equipment Co of Eastern Oregon, inc
 
The micro switch has 3 terminals on it:
NO = Normally Open
COM = Common
NC = Normally Closed

The ones we use on pressure Washers are NO and COM. The reason being when the pressure is off of the switch we want the power off of the fuel. Normally open makes this possible. When the little pin pushes the switch it activates the fuel by closing the switch.
 
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