ok first off i would like to fill you in on some history. i started renting this house from my grand father last fall, made it through last winter with no problems. this winter season started out fine but then one night i was awakened when i heard water rushing out of a blow off valve. the system just stoped regulating the pressure and it kept getting to high so i started to control the flow of water to the system manually and that worked good for about a month.

Now i have the problem where i can not get it to build up pressure, it appears that 5psi is max. i have the water supply to the system fully open, and i do not notice any major leaks. i went to a few of my baseboard heaters to try and bleed the lines but water came out. i did not bother to check all of them, should I have to?

My dad thinks it is the blow off valve in the back of the boiler because it doesnt seem to seal good however it is a relativly small drip, (fills about a 3 gal. bucket in about 4 or 5 days) my thought is that when it heats up it should be able to build up pressure because the water entering the system is greater then whats leaving right?

I am looking for any suggestions on what i should check out, ideally i would love to have a repair man come and fix it but money is tight for me, and my grandfather has not been doing well so i really do not want to bother my parents for my grandfather with this right now. thank you for any help and i am sorry for a long drawn out post, just trying to put out there everything i know.

 

You need to check a few things:
1) Pressure reducing valve at the water fill line - does it make a flowing sound when you open it manually?

2) Expansion tank (btw, which type is it - a big barrell somewhere up there?)? It's probably waterlogged, which was likely the original reason for blowing off the relief valve.

Your blow off valve leaks because the seat is bad - it was closed fully before, but after the overpressurization incident it opened and never closed right again. Sometimes it helps to manually open it a few times (warning: lots of water comes out!) and it will seat better - but not guaranteed.
1 gal/day is quite a drip, but the water fill system should handle it OK.

P.S. I'm not an expert, but had a similar problem in the past...

 

Pat, when the relief valve spewed out the water, it would have been advisable at that point to do something about the problem... the reason that happened is most likely because the expansion tank required service. That's problem #1.

#2 is that the relief valve is probably way old, and after it opened and spewed, it is not sealing properly anymore. It should be replaced.

#3 is that it seems now your 'pressure reducing valve' has become plugged and is not allowing water into the boiler.

How handy do you judge yourself? Do you have wrenches and things?

If you want to have a go at fixing things up, we will help... yes? OK then, take a bunch of pictures of your system... all the piping around the boiler and such... and take a few from a distance back so we can see the whole thing... set up a free account at Image hosting, free photo sharing & video sharing at Photobucket and upload the pics there, come back here and drop a link to your photo album.

[edit: bigblackjack beat me to it! and is right on the money! But, if you can't get water into the system, you might not want to open the relief valve... cuz you will only let more water out and you don't wanna do that!, not yet...]

 

thanks for the replys, i happen to have a few pictures handy, i will try and get some better ones later.(no computer at the house). i would judge my handiness as willing to learn, ie. i know how to turn a wrench but have very little knowledge about this topic. i will try and call off everything to the best of my knowledge in the pictures i have, feel free to correct me.


picture one:


the red handled valve at center frame is the water supply comming in and heads to the expansion tank. Now i assume that the larger copper pipe just above that in the picture is my return line for the system and the copper pipe just to the right of frame is what feeds the hot water to the system.

one question i have is what is the "fitting" directly above the expansion tank in the larger copper line?

picture two:

this is just a different angle i had of some of the piping, im sorry about the quality of the pictures, ill try and get some better ones if needed.


As far as the releif valve, i have tried to flip it open and have had very little success in getting it to close however i feel pretty conifident in replacing that, it doesnt seem to tricky and i know where it is. (back side of boiler)

as far as the pressure reducing valve, i am not 100% sure where that is and if its clogged can it be cleaned or should it be replaced?

And finally if the expansion tank is waterlogged, what can i do about that?

 

Pat, the pics are fine... thanks... tells me everything we need to know at this point.

This is probably going to be easy.

First, tell me what the label on the expansion tanks says. It SHOULD say FILL-TROL, and NOT EXTROL .

IF it does say FILL-TROL then it is the correct tank for your system. The brass part above that is a special type of valve that replaces a 'normal' pressure reducing valve, so you can stop looking for that.

And it looks fairly new, so I'm going to take a guess that the bladder inside is OK...

It might not be a bad idea to change the relief valve first, since you won't have to drain as much water... and you should look around the system for any valves which you can close to isolate the boiler from the rest of the system... again, so you don't have to drain everything... the less water you have to drain, the better. Hopefully you have such valves.

To get the boiler pressure in the system up to where it needs to be, all you have to do is add air to the valve on the bottom of the expansion tank. It's a normal tire valve, and you can use a bicycle pump or a small air compressor. As you add air to the tank, the valve above will open up and allow water into the system... so watch the pressure gauge on the boiler... add the air slowly and allow time for the system to stabilize the pressure...

See this PDF (page 5) for explanation of how that fill valve works, and why you MUST use the proper tank matched to it.

If the tank is waterlogged, it may be as simple as just adding the air as described above. If when you are adding air, you find that WATER is coming out the air valve, then the bladder in the tank is broken and the tank will need to be replaced... again, ONLY with a FILL-TROL type tank, which you probably will NOT find at HD or Lowes... and don't let anyone tell you that you can use a standard Extrol tank, because if you do, you won't be able to get any water into your system!

The cast iron thing above the expansion tank is an 'air scoop' and it is supposed to catch the air in the system and pass it to the brass can on top... that brass can is a 'float type automatic air vent'... there is a float inside that drops when it is full of air, the valve on top opens, lets the air out... water comes into the can, lifts the float and closes the valve. The cap on top of that can is supposed to be LOOSE so that the air can escape. If you loosen the cap and it leaks water, it too must be replaced... cheap part can be had at HD or Lowes...

There is another cast iron thing to the right of that... and it is a 'check valve' which only allows water to flow one direction in the system... it also stops 'gravity flow' so the hot water from the boiler stays in the boiler when there is no heat call.

 

Just looked at the pics again... you do have valves on both the supply and return lines... excellent... the one on the supply line looks kinda cruddy though, so I hope it works OK... and it also appears there may be another old leak right where the supply line comes out of the boiler... can't tell for sure... post closeups if you want.

When you replace the relief valve, you should install it so that instead of the discharge pointing across the boiler, it points to the side... and then come off the relief valve and elbow down to the floor with another pipe so you can put a bucket under it, and also so that nobody gets spewed upon by steaming hot water if they should happen to be standing there at the time.

You might find it easier to install a short nipple in the boiler and install the valve on top of that nipple...

Those relief valves come in several varieties... with various combinations of 'sex' threads, so make sure you get the one that you need.

 

Quick exp. tank test (tap test)- with the end of a screwdriver
tap the top half of the tank (water side) it should go thunk.
(indicates water) Now tap the lower half, it should go tink.
(indicates air) If bottom half goes thunk, either the diaphragm
has a hole in it, or the air side has lost it's pre-charge. (12psi)
If the top half goes tink, there is no system pressure on wet
side. Air side pre-charge must be tested when there is no
system (water) pressure agaist it.

Looks like 30# relief valve is 3/4F X 3/4F, look at tag for BTUH
rating. Code calls for relief to discharge within 6" of floor.
I usually go 4". If you get pipe cut and threaded, make sure
horizontal run is long enough to swing vertical run into a bucket or you will just have to back it out of the elbow to
get bucket in or out.

What do you think Trooper?

 

Here's the missing Amtrol Extrol link:

http://www.amtrol.com/pdf/extrolbrochure.pdf

Like Trooper said, see page 5

 

Thanks Steve for adding the link I forgot!

I'm not too 'down' with the 'tap test' for expansion tanks... I'd just as soon drop the pressure and put a gauge on the schrader... that way, no guessing, or interpreting the different 'sounds'.

Also, with the Fill-Trol system, one doesn't have to drop the boiler pressure to check the tank. The system pressure will always match the air charge... so if you put air in, and the system pressure goes to 12, you know there's 12 in the tank... unless of course a vermin gauge is living on your boiler!

The only caveat to this is that if the Fill-Trol tank has a busted bladder... things can get all whacked out.

 

Trooper- yeah, I get the gauges out too. When I'm going in
cold on diagnosing a problem, I run simple tests on all the
"stupid stuff" first, then refine my approach the further down
the logic tree I go. Haven't seen a Fill-trol in years- not too
common in these here parts. You are most welcome for the
link.

 

well i did that tap test and the top went thunk and the bottom went tink, i had put air in and it seemed to do the trick. it still had pressure this morning when i got up so i am keeping my fingers crossed. as for the releif valve, its around the back of the boiler, i think what you guys are seeing is an old one that had just been set on top.

i appreciate all the help, you guys have given me a better understanding of how this works, it made my week getting that pressure upBeer 4U2