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-   -   SAFGARD 170SV low water shutoff (http://www.diychatroom.com/f17/safgard-170sv-low-water-shutoff-159573/)

t_maher 10-09-2012 08:17 PM

SAFGARD 170SV low water shutoff
 
My boiler decided to not fire up this morning. I detected 120v to the emergency switch but no power from the SAFGARD low water shutoff. Either the shutoff is faulty or i actually have low water in the heating circuit. I read somewhere where the shutoff sensor s/b cleaned every 5 years. Is this true? How do i determine if there is actually a low water issue or if the sensor is bad?

Patrick Eubanks 10-09-2012 11:51 PM

boiler
 
The low water cut off should have a sight glass that shows the water level. You can open the blow down pipe/boiler drain and let some water out of the system. Listen to see if new water is entering the boiler.

techpappy 10-10-2012 12:32 AM

There is no sight glass on hot water LWCO's just for steam boilers normally. Hopefully you have isolation valves going to zones..if so then turn them off and drain boiler until no water coming out of relief valve ..that is if relief valve is at top of boiler you can lift the lever to see when water is below that level..then remove sensor probe and clean with steel wool or sand paper..reverse process and try to see if boiler limit is made through LWCO

open valves and start boiler just googled re safgard and they recommend cleaning probe every 5 yrs. on domestic boilers and annually for commercial applications

make sure there is power TO the LWCO first

Can also get air around probe preventing current to ground ( check this by loosening probe allowing any air to escape then re tighten....and also ..the probe can be rendered ineffective if loss of ground where it threads into boiler..this can be caused from too much pipe dope or teflon tape on threads or excessively dirty threads ...usually from corrosion

beenthere 10-10-2012 05:27 AM

Does the pressure gauge show any pressure in the boiler.

t_maher 10-10-2012 10:56 AM

Quote:

Originally Posted by techpappy (Post 1027884)
There is no sight glass on hot water LWCO's just for steam boilers normally. Hopefully you have isolation valves going to zones..if so then turn them off and drain boiler until no water coming out of relief valve ..that is if relief valve is at top of boiler you can lift the lever to see when water is below that level..then remove sensor probe and clean with steel wool or sand paper..reverse process and try to see if boiler limit is made through LWCO

open valves and start boiler just googled re safgard and they recommend cleaning probe every 5 yrs. on domestic boilers and annually for commercial applications

make sure there is power TO the LWCO first

Can also get air around probe preventing current to ground ( check this by loosening probe allowing any air to escape then re tighten....and also ..the probe can be rendered ineffective if loss of ground where it threads into boiler..this can be caused from too much pipe dope or teflon tape on threads or excessively dirty threads ...usually from corrosion


Thx for the feedback.

Isolation valve is present. i am pretty sure the water level is ok because my hydroair blows hot when i call for heat.

I can just forgo all the detective work and buy a new unit and install. But i am curious as to what is causing the control to fail. I might buy a new unit anyway AND do the detective work, probe cleaning...etc. I'll keep you posted.

techpappy 10-10-2012 11:30 AM

typically the probe just gets dirty thus preventing circuit to ground through the water..clean it and should work


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