HW system troubleshooting

Timco

I'll be peeling the skin away today. No air seperator...just a scoop on the outlet manifold off the top. I lost a lot less pressure after purging well, but the boiler will not hold press. I fill the system to 20, isolate the boiler, and watch the gauge fall in 2 minutes to 10, and 30 min later to 0. If I fill an isolated boiler, the valve pops at 20#, but if I fill the system, I can put it to 25-29 and isolate it then. Since leak would be in the combustion chamber, would I see water on the floor, or is the insulation mopping it up?

Thanks, T

Timco

I checked my gauge against a good one on the drain spout, and I absolutely have no visible leaks in the system, and I have a new exp tank pre filled to 15#. Every night I fill (cold) to 10#. When it gets to 180*, I am up to 20#. By morning when I turn it off for the day, I am at 0#, and the highest zone has begun to empty. (single story bungalow with no pipes in the slab) I eliminated the old gravity exp tank pipe at the boiler, and am sure I have no ponpc's left on the system other than the exp tank (honeywell 4.4 gal). The kicker is I never see any water around the boiler to suggest a leak in the exchanger (teledyne-laars). When I fill it cold to just below 30# (and not run it), in a week it drops to 20#, but no water around the boiler. Press valve is always dry. Is there a way to inspect the exchanger for leaks? The prev owner's repair guy only put a shut-off valve on the inlet side...lot's of good that did to check the boiler. Is there an inspection window, or way to pek in there? It seems to be the last straw. No steam comes up through the roof co vent.

What do I check now? How could I lose soo much pressure over night?

Thanks as always,

Tim
SLC

Al Letellier_9

leak location

theonly thing I can think of Tim, would be to isolate the boiler from the system, even if it means installing another valve. There could be a leak in the walls in some zone piping that isn't showing up but is causing some other hidden problems. I assume that you are shutting off the feeder valve to the boiler while this pressure drop is occurring? If not, your fill valve could be faulty and is letting boiler water out of the system. Why do you shut it off during the day? Is this normal practice or are you worried about the leak? What model T/L boiler do you have? Is it a combo with and indirect or a separate boiler and water heater. The pressure has to be going somewhere. Isolate as many components/zones as possible and test each individually. You WILL find the leak eventually.
Did you power purge all the zones? If there is air in the system, you're just trying to compress it by adding more water and that doesn't work. any air trapped will increase in pressure but may escape through vents in the system.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Timco

The T/L unit is a JVS 160H, 131,000 BTU. Small unit, all in one, tankless. I do shut off the feeder as I do not have a backflow preventer on the system. When I say shut the system off, I mean turn down the t-stats, but I do worry about the leak as it is down to 0# by morning...in 12 hours or so. Would not want it to fire at that pressure. I did power flush it, but it is a 2-pipe system, and the rads tap off of the 2 pipes. After power bleeding each zone, I bled the rads. All heats well, and no air or noise is apparent.

So you recon a iso valve on the boiler is next?

T

Timco

I am installing a ball valve on the 'goesoutta' side now, and will isolate the boiler. If the pressure drops, am I to assume the boiler needs to be replaced, or can I purchase a new heat exchanger?

Thanks,

Tim

RoosterBoy

howdy Tim.

maybe when you add water you arent adding much water like you may only be adding a pint or so andd it is sufficent to bump up the pressure ,... so say you had a taco air vent or whatever eliminating "air" perhaps what is happening is you have more "air" in the system than you realize,i know very little about the particular boiler however,turn it off for a few hours and get the temp down,Then add water,disconnect the circ pump and run it while doing so...run the water pressure up to like 25 or so....let the pump run a hour or so,get some coffee come back,..what you are listening for now is the sound of water,if you Hear water,you have "air"in the system,hit the pressure relife valve a bit with some 3/4 " copper an then open it and quickly let it shut again,if you hear a hiss then water leak out you just got rid of some air..the next thing is if the sound of water is really loud you have entrained air,thats bad,buh it is also good that it is moving about the system,what you want to do is get yourself a washing machine hose and connect it to the boiler drain,open the valve and blast some of whatever is in the system out into a white bucket. If what you see is really brown looking mud stuff,well two things could be happening one is you have a leak in the lines under ground somewhere,unlikely though..more likely you have alot of rust in the system. if so ,then, maybe your boiler needs alot more help....you could try pumping water into it and draining it out the bottom of the boiler first though.till it runs sorta clean.
Then the thing is to run the temps up a bit higher than say 160 180, try170 190 and just let the circ run constantly crank up all the t stats and keep an eye on the pressure and temp...the first time the boiler quits running turn it off,and take note of the pressure temp gauge. when it cools down to 100 see what the water looks like comming out of the boiler drain..a short Blast of water in a white bucket shoul be fairly indicative of what it rolling thru the pipes. if you have lots of brown stuf it is probably a product of oxidation.its every where.in the boiler in the fields in the coils..it is costing you to run the thing more per month than it would cost to have someone take a look at it. if it is sorta clear,and you arent hearing water rushing about any more, then you flushed it a bit and have likely removed alot of the problem...it curious just how much destruction a little air can do to the interior of the boiler system.after this, i'd hook the circ back into the control box and watch the pressure gage for a couple days maybe check it in the mornings...if you lose a couple pounds then thats normal for new water, sorta. if it zeros out though your boiler needs somebody with a wrench or sawzall or both,as its likely in for a vacation from its former duties. rebuilding boilers is a skill and generally not worth the time and hassel so,having a couple opinions on the field will be important before buying the boiler. the pipes in the field may be ok may be not. you can run some new pex pipe sometimes for less $ and hassels than fixing other existing field piping fittings. a new header with zone valves and a means to purge the individual zones,and a pressure regulating valve spirovent and copious elbo grease you could throw some dollars into the piggy bank every month from then on. as a thought...we have some really efficent boilers and burners and controls these days. good luck.

Timco

Weez,

Thanks soo much for the great advise. It took very little water to get back to 10# prior to purging the lines. Since re-filling, and bleeding out the lines with a hose on the purge valves and the fill wide open, alot of air came out, and it lost very little to no pressure last night. But when I isolate my boiler to check for a leak in it, you can watch the pressure drop from 20-10 in 2 minutes. The boiler will not hold 20# when isolated. The system will, but not the boiler. No water on the press valve. Does this matter?

Thanks again,

Tim

RoosterBoy

Tim, i think you have discovered the minor technicality

as i call it.

here is what i think i "see" inside your boiler is a leak and it is either a piece such as the relife valve(which you have checked already) or it is from a pinner leak these leaks can be in the firebox on oil burners on the target wall ,between sections,or tru the tankless coil.if you have pressure Increases it generally due to aleak tru the coil into the boiler....if you dont see water then its mostlikely within t6he boiler itself. if it takes 1 quqrt to pump the pressure back up then you likely have a leak very near the top ,i have seen a pipe that was leaking near the top of a boiler over the outside that would turn to vapor and vanish and i found it by taking the "Skins" off the side and back and top.......it would leak and because the boiler was Hot there was no real visible leak on the ground.another time i found a very small Pin hole leak in a pipe...quite by accident it was shooting the water way far away in almost an invisible pinner stream over to a wall...it occured to me that the room was Damp and yet there was not enough water to actually See. all i did was replace the offending piece of copper pipe. and thin the first instance all i did was tighten the fitting!. then another time it was leaking from between the sections all i did was tighten the draw bolts on the boiler, and not by much at all. seems that it would only leak some place between cold and rolling. another time my buddy and i spent all thanksgiving evening and the next morning trying to seal a leak with boiler seal so we could make it thru a very very cold night and make it to a part house the next day. we dumped pepper in it also then we found the CRACK on Top of the boikler. You cannot fix a crack properly so dont try it. if you see water comming out of a copper pipe or "black iron pipe" this yoyu can fix easily enough....taking the skin off the top of the boiler often bringss another whole new world to light. look and see all you should need is a screwdrive or a phillips or a nut driver. good luck.

One last thing....a pressure relife valve may leak thats ok...buh plugging one up in any way thats a definite NO !NO !.*~/:) if it is plugged say due to leaking endlessly for yeasrs untill it is thouroughly encrustated with chemical deposits you are well rid of the piece of junk and get a new one...here is another great reason to take the skins off,water likes to keep going where its been going...and it can leave very clear indications just where it might be comming from

Steamhead (in transit)

Something is definitely leaking

the boiler should hold 20 pounds at least. Is there an air separator with a vent on the boiler?, If not, it may be a pinhole as Weezbo says. Sometimes these are very hard to locate.