boiler under pressure, can S1156F's be adjusted?

Rex Wilson

Hi. I have a Repco 75k BTU hot water boiler, and it is building up pressure lately: dripping from the relief valves. If I open a relief valve, there's a big gush for a couple seconds and water continues to flow, then, after a few seconds of flow, the S1156F kicks in and I can hear water being added to the system. Given that the water runs for a few seconds before the valve kicks in and starts adding fresh water, I'm guessing that additional water was somehow being added to the system, incorrectly.
After I manually purge the extra water, the system runs ok for a few days, then starts dripping again.
Is there a way to adjust the S1156F to allow in less water? Might there be other causes? Thanks.

bigugh_4

you have just described a expansion tank that is full of water,

If it a diaphgram tank it may well need replacing, and if it is just an ordinary tank it needs draining& or and perhaps repiping.

Rex Wilson

Thanks for the info. That makes a lot of sense. It's an Extrol, with diaphram. You say it "may well" need replacing. Is there anything I can do/try with the thing before replacing it?
Thanks

Steve Eayrs

Your 1156 pressure reducing fill vlv does have an adjustment on it. but I have never seem them go out of adjustment on their own. If you spin the top threaded "flip lever" off, you will be able to lift out the little shaft, loosen the set nut, and adjust the pressure, by turning it down for higher and up for lower pressure. (This of course is if someone has been messing with it and increased the pressure.

Besides the expansion tank, as already mentioned, or the above possible, the fill vlv could also be stuck open, and allowing water through it, when not wanted. If there is a lot of corrosion I usually just replace it. Its cheaper than the labor trying to get the old one cleaned up, and having it still not work good, 1/2 the time.

On last possible.......Did this system recently get piped up or have some piping changed? Did you recently extend/add on to a heat zone? Is the fill valve feeding the boiler system on the suction side of the pump?
Could be your system thinks it needs more water every time the pump kicks on and the pressure drops at that point. If so move the boiler feed.

Maybe get one of Dans books, so you can understand better how this happens, and where best to move the feed to. I can't remember which one may best describe this, but someone here will know. (pumping away?, primary/secondary?, other?)

Steve

bigugh_4

yes there is

a way of 'feeling' the ex tank if it 'rings' when tapped like it is full it is. if it 'feels' heavy it is full. If the air stem is on the top and you get water out of it when pushed, like a tire valve it is full and a full extrol tank is just plain shot!
They are not expensive-- replace it!

Earthfire

extrol

You may just have an undercharge diaghram tank. They need to have their air charge checked anually as part of annual service. Air charge should be set to match system cold fill pressure,usually 12 psi. Even a new tank can need pressure adjustment.While you have the extrol off the air scoop install a 1/2" ball valve in to the bottom of the scoop(1/2"gas cock with the small handle works fine)thread a 1/2" tee into the valve and thread the extrol into the bottom of the tee. Thread a 1/2"x6 nipple into the side of the tee and attach your water feed valve to the nipple. Use 1/2" x 21/2"nipples between the scoop, valve & tee. Gives enough clearance to operate any fill valve that I have come across. OPEN the ball valve and leave it open. Only gets closed to service the extrol and fill valve, And you don't have to drain your system again to do it .

Rex Wilson

Many thanks for the helpful replies.
I'm thinking I don't need to completely drain the whole system to mess with the extrol. So long as I have another drain valve open somewhere?

Earthfire

airing up an extrol

On the bottom of the extrol there is a plastic cap that screws of. Take it off and you will find a schrader fitting (like a tire valve) that is where you check the pressure and adjust. If you push in the schrader and you get water the tank is scrap. If you get air take it off and proceed as I suggested earlier.The extrol must have 0 psi pressure on the water side to be checked and adjusted properly.

Rex Wilson

did what you suggested. I got air, not water (rather foul smelling air, at that!). I'm going to try topping it off with more air to make sure it's at 12 PSI.

Earthfire

Bicycle Pump

Will do it if you don't have an aircompressor handy and a good gauge to check the pressure

Rex Wilson

Hi, Steve, and thanks for your help.
No, I haven't changed any piping lately.
The expansion tank has air in it.
The fill valve is on the return side of the loop (and on the suction side of the pump... it's not a "pumping away" system). The expansion tank is on the feed side of the loop. I have two such identical boilers and set-ups side by side. One seems to be working ok (though it runs the first floor, and the leaky one runs the 2nd floor, so it's possible that gravity is introducing a little more trouble into the 2nd one).
Another test I did: if I open a drain and watch the pressure gauge on the front of the unit, the fill valve will kick in and start adding water when the pressure drops just below 20. Shouldn't it be waiting until the pressure hits 12? That's what made me suspect that the fill valve needed adjusting.

bigugh_4

OK

Now to put the proper pressure in it , It must be free of the system pressure. that is; make sure the system pressure is not upon the inlet to the ex-tank, then place the pressure at 12 psi. then return the system pressure to the tank. this may be done without removing the tank from the system. You'll have to asess how to do it. the pressure at the tank inlet MUST be at zero when pressureing up the tank.

bigugh_4

With that info

I bet the fill valve leaks! you may have to replace it. Repairing them has been a looseing hassel for me.

Rex Wilson

I replaced the fill valve. While I was tinkering, I also drained the system and made sure the expansion tank had 12 PSI. I now seem to be a happy camper (after an embarrassing second trip to the plumbing supply counter, as I hadn't yet learned the subtleties of the threading differences on the fill valves. I now know that a 1156F is different from an S1156F).

Many thanks again to all for the very helpful information.

brian_25

too much pressure

just a thaught . not familar with the repco boiler but if this boiler has a tankless heater you could also have a pin hole in the tankless alowing domestic water to enter the boiler . this dosent happen often but it does happen. i do agree that the ex tank is your most likely problem.