T-stat. not reaching temp.

We've recently had some issues with our oil fired boiler that resulted in a combustion chamber liner being replaced, along with some new valves. That's all great, but our issue now is the thermostat won't reach the desired temp. - currently we have it set for 67 and it doesn't seem to go beyond 64. Just for fun and because it was something I could do myself, I even replaced the t-stat. to no avail. Called the tech back and he spent about 5-minutes and said he increased the temp. at the boiler and that should do it. Well, it got up to about 65, and that was it and now I'm getting a bit of a run-around with the heating folks.

I'm wondering if there just might be air in the system, and if so, how I would go about bleeding the lines on my setup? We have baseboards throughout the house (copper w/ fins), and I've gone through and cleaned each of them out so there isn't any dust/pet hair causing issues. There are no bleeders on the baseboards themselves.

Below is a link to some photos of our system. Does anyone have some suggestions on what I might check next? And while the last tech said he increased the temp. at the boiler, is it really suppose to be near the boiling point on the gauge (see photo)? I thought that was kind of bad for a hot water system if things suddenly begin to turn to steam and such.

Furnace Photos

Thanks for any comments - I've enjoyed reading this forum and have picked up a little knowledge regarding this type of system but am far from really knowing the proper troubleshooting process.

 

Your gauge shows 205 deg and 25 psi. So, your boiler is hot, pressure a little high.

When the thermostat is calling for heat, is the red circulator pump running?

If the plumber replaced some valves, what valves in particular and why? Presumably he drained the system to replace the valves, after which he should have bled the system of air - that's part of the job.

If there are no bleeder valves anywhere, then you can try a power purge. I see there are hose bibs on what seem to be two return lines - in series with isolation plug valves.

Cool down the boiler first to avoid flashing to steam. [not only that... you don't wanna dump a bunch of COLD water into a HOT boiler!] [and turn off the power too! - NJT]

Shut the two plug valves, open the isolation valve ahead of the automatic fill valve, and bleed from the hose bibs, one at a time through a hose to a floor drain or into a bucket (and watch for air bubbles). Then open the two plug valves.

I don't see a safety relief valve in your pix. Do you have one?

 

Thanks Mike. Sorry, not sure on the names of the valves, but they are the two that can be seen in the 10th photo (the one is a bell shape and the other is just in-line with the plumbing). The original were apparently corroded to the point that the tech felt it was best to replace them. I didn't see if he bled the system somehow after replacing these two.

I do hear the circulator pump operating after the burner shuts off, and while the t-stat. is still calling for heat.

There is a relief valve located on the top-left of the boiler (almost behind the red circ. pump). It's at the top of the overflow pipe discharging into the plastic pail that can be seen in the last photo. Rarely do I find any water in this pail however, which I'm thinking is a good thing.

Thanks for the tips on the power purge - sounds like something I can handle. Here is hoping the isolation plug valves operate smoothly!! Thanks again for the advice.

 

OK, I see the relief valve now.

The bell-shaped thing is the pressure reducing valve (a.k.a. automatic fill valve). Make sure the red-handled isolation valve ahead of the fill valve is open before you start your power purging. I'm thinking that if the plumber replaced the fill valve, he probably drained the system; is so, air could be your problem.

The plug valves can be turned with a long crescent wrench. Both now show they are open. Turn the valves 90 deg, one way or the other. They are shut when the bar is cross-ways to the normal flow direction.

Piece of cake.

 

Sometimes them plug valves can get tight turning... if they don't seem to wanna turn, you can often get them turning by _slightly_ loosening the nut on the back side... and carefully 'tap' 'tap' with a tapping device (I didn't say wail on it with a sledge! even though you might want to! )

Those valves are tapered cones, and they fit snugly. Carefully tapping on the bottom bolt can sometimes loosen them up.

Since the nut will be loosened, there is a possibility they will leak when/if you loosen it... if so, that's actually kind of a good thing, because it means the valve isn't jammed tight... just snug the nut up again to stop the leak.

But of course, try just turning them first, you might get lucky! They do appear to have been open/closed at some point after the pipes were painted, so you might be OK.

Below the temp/pressure gauge on the front of the boiler is a 4x6" gray box... that's your AQUASTAT and is where the temp controls for the boiler are. When you are done purging the air, slip the cover off that box and set the temp control to 180...

 

In pic #8, between the joists, there is an 'air purger', or 'air scoop'... on top of that there should be an automatic float type air vent with a 'tire cap' on top of it. That cap needs to be loose to allow air to escape. There is a float inside that is supposed to close the valve when there is no air present...

Sometimes they get to leakin'... looks like yours has at some point. Most ppl just screw the cap down and forget about it when that happens. Which is OK, as long as there is no air in the system to expel. So, if the cap is tight, loosen it. If it leaks, replace it.

 

I wonder what was behind painting the piping silver? Just for looks? In some cases, the painter even painted some copper nipples and fittings.

I presume that the unit heater was added with the idea of a shop or other human activity in the basement? I notice a cat box on the basement floor, so maybe the cat likes to keep warm when he's taking care of business. But otherwise, you could valve out the unit heater and save a little fuel. It looks like a strap-on aquastat turns on the unit heater's fan anytime the heater's supply pipe is hot. So, just valving out the unit heater should keep the fan from running - and if you decide you need some additional basement heat, you could just open the valve(s) to the unit heater.

I would think the boiler itself, without the unit heater in service, should be enough to keep the basement well above freezing and your living area floors reasonably warm.

 

Thanks for that suggestion, Trooper. My system has four of those valves. After many years of disuse, I had to turn one or two of them with a 24" pipe wrench. Now, I shut them whenever I need to drain the system for maintenance, so only the boiler has to be drained - thus the valves do get exercised periodically.

It doesn't seem that putting putting mucho leverage, via a 24" pipe wrench, causes any problem to the valve. My valves have square heads, unlike H8Monday's, so it's easier to put a pipe wrench on them.

 

I'm guessin', yeah... my dear old Grandfather painted every durn pipe in his basement... and he wasn't NEAR as crazy as I am!



Welcome... it doesn't always work though... and the ones that H8 has, I'd be skeert to put too much force on them for fear that the tab might break off, and they also have a hold drilled through, I guess that's for the rebar rench to fit into? Just be careful that ya don't whack 'em so hard that you peen over the end of the stud.

 

Good Lord, that's a boiler straight from Hell And what's the story on the red barometric vent's flapper?

 

Well... ya know how when you paint the rural mailbox... and you only have a little red paint left in the spray can? and you don't know what to do with it?... sadly though, that damper has gone to damper hell. There's a purty Field there now... well, not _there_, but in the vertical section below it.

"If it moves, shoot it.
If it doesn't, paint it."

Sorry for all the weirdness, but it IS New Year's Eve, and there ARE 10 empties already!

HAPPY NEW YEAR!

 

You need a new picture, Trooper. One that doesn't have that test switch hanging by its wires.

 

I KNEW you would catch that furd! yeah, that's gone too... but there's all kinds of other junk hanging off there now too.

 

Sensor me if you must! I too have a few empties! But i'm beginning to think that Trooper even though you certainly show competence and brilliance you really are a high tech moonshiner at the core!

That picture looks like some kind of well maintained high tech moonshine equipment. I probably had too much to drink here already on New Years Eve! But I probably can't injure someone here at the keyboard!

HAPPY NEW YEAR!!! and thanks for all the help you give people. Who knows how to measure what you've done for the folks here on the forum?

 

Trooper: I'll be calling your AHJ Monday a.m. Tell me again your street address?

That flooring looks like vinyl-asbestos tile. Call a licensed asbestos remediatian contractor and have it removed, immediately.

Mike Speed, over and out - 12/31/09, p.m. See you next year, late in the day.

Ignore any of my posts made within the past two hours.

 

Thanks for all the help and suggestions guys - I really appreciate it. No idea why the pipes are painted silver like they are...customization perhaps

While I haven't had a chance to try purging the air, I did attempt to get those plug valves to turn. It took a bit, but with a fairly long crescent wrench, they did both begin to twist, so that gives me hope!

Not sure on the original purpose of that unit heater either - it doesn't seem to work. When plugged in, there is no fan at all, so currently, I believe it is closed off from the rest of the system.

Oh, and I did pop open the aquastat and dialed it down to 180 as suggested. Once I get any air purged, I'll see how it all works out. Thanks again to all for your replies.

And Trooper - that is a wild unit you have there. Very nice!

 

What is the setting on the strap on aquastat? Try turning it all the way to it's coolest setting and see if the fan works... could be that the fan is NG.

Are those valves on the in and out to the heater open? Do both pipes get hot?

Might could be full of air too... is there an air bleeder on that fitting on top of the unit?

I had a couple of those old Trane unit heaters here in the corner of the garage for years and finally disposed of them, but now I wish I hadn't... I've got a use for them now, and it's gonna cost me to replace them.

Another look at the pictures and I realized something about that unit heater... with the valves to and from the unit fully open, it would serve as a SYSTEM BYPASS... since water, like electricity will take the path of least resistance, if the valves are full open, a good portion of the water that should go to the system would get diverted through the unit heater. So, if you do decide to ever put it back in service, you might consider only opening the valves just enough to get usable heat out of it. On the other hand, SOME bypass might not be a bad idea, to keep the return temps to the boiler up... (yes, those do appear to be GATE valves, and you really shouldn't use them for throttling purposes... but, well, there is no but...)