Help! No hot water (from gas boiler/furnace)

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Old 08-09-13, 05:33 PM
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Help! No hot water (from gas boiler/furnace)

We're not getting any hot water from our gas furnace. Tbh I don't know much about my current water heating setup and my dad (who I'd usually call for these problems) is unavailable right now. But what he's told me in the past is I don't have a hot water heater just a hot water tank and the heating is done via the furnace. Sound right so far?

I noticed earlier we didn't have any hot water and thought the pilot light may have gone out, as it has in the past due to a flooded basement. But the pilot light was fine. Instead the low water cutoff was activated and had a red light indicating such. The furnace pressure was also reading 0 psi.

I know we have a pressure reducing valve (B&G FB-38TU) that my dad has in the past mentioned I can open if the pressure is a little low for our radiators. I barely lifted up on the handle and right away I heard water rushing by and the furnace kicked on. The pressure slowly went up to 15 psi. Then, 3 electric solenoids (?) In the general area started clicking on and off. And something (it sounded like one of solenoids) started making this very loud whistling sound every ten seconds or so for 5 seconds long at a time. I let it go on like this for 15 minutes thinking it might just be reaching temperature.

Anyway the whistling still continued so I opened the hot water return valve near the bottom of the tank and dropped the pressure. It did come out steaming hot. When it got below 10 psi the whistling stopped. Opening the PRV a little to get the pressure back up cause the whistling again.

After Googling videos on the pressure reducing valve and hearing they break often, I shut off the intake and discharge valves on the PRV and opened the bottom up to see if the screen was clogged. It ended up braking into many pieces in the process (like the videos showed).

I ended up turning off the furnace, and draining the water tank until the pressure reached 0 and the low water cutoff activated.

Thank you in advance

Any ideas what the problem is, and why the whistling? Can I get a new screen for the PRV or should I just get a whole new PRV?

Sorry it was so long, I took the "No detail is too small", advice to heart.
 
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Old 08-09-13, 05:49 PM
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Im sorry to say but you may get seriously injured here...or death can occur...

Sounds like a steam boiler you have there and you really sound like you do not comprehend what you are doing IMO...

Adding cold water to a hot boiler and that thing can blow up from thermal shock... If relief valve blows off it will literally melt your skin off like butter....

This can happen from what you are doing...

Do you have family in the home???

First off leave the emergency switch off... Do not turn it back on..

You can take some pics and post back, but from what you explained I think its best to call a pro at this point... Especially that you called it a furnace.....
 
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Old 08-09-13, 06:56 PM
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Lol you're correct, after Googling it is absolutely a *boiler*. A Weil-Mclain CGa in particular. Since it is also used for heating our hot water (not steam) radiators I was using furnace/boiler interchangably

I did know that cold water over a hot BOILER could cause it to crack and lead to big problems, but for the 20 minutes I had been in the basement the boiler never kicked on so I was assuming it was cool enough (probably a dangerous assumption). But since it's the summer I thought the only reason the boiler would kick on is to heat the water, and the low water cutoff was stopping all the water from entering the boiler.

Here are the main components:

Boiler: Weil Mclain CGa boiler (not sure series 1/2)
Hot Water Tank: Weil Mclain Plus 40 Series 3
Expansion Tank: Amtrol #30
PRV: B&G FB-38TU
Low Water Cuttoff: LNA1203S-1

I don't think I'm as in over my head as it might seem from my lack of vocabulary. I'm pretty mechanically inclined. I'll take any help you can give (and not hold you responsible regardless lol).
 
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Old 08-10-13, 07:33 AM
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Yes, cracks are one of the problems that can occur with cold water into a hot boiler... BUT... there's a FAR worse scenario.

If the boiler is hot enough (it has to be pretty hot, but heed warning anyway!) the cold water that is added can INSTANTLY FLASH TO STEAM. When water flashes to steam in expands SEVENTEEN TIMES in volume. When that happens, there is no relief valve that will expel the pressure fast enough to prevent an EXPLOSION! If you are standing next to the boiler when this happens, you won't have time to say your prayers before you die.

Yes... it is a somewhat remote possibility, but it CAN and HAS happened, so please understand this!

The FIRST thing you need to troubleshoot is figuring out WHY the pressure dropped to zero. WHY did the LWCO kick in? WHERE did the water in the system go? Until you get that part sussed, anything else you do is a temporary band-aid. The problem will return.

Remember that a boiler system is CLOSED. If you are losing water it means the system is not sealed. ROOT CAUSE is what you need to find.
 
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Old 08-10-13, 11:54 AM
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Thanks for the advice on steam. Now the boiler has been sitting off over night so is definitely cold. But am I correct in assuming my hot water is the only reason for it to kick on in the summer? I know for a fact the hot water tank is just that, a tank, and not a hot water heater.

As for any possible leaks, the main leak that I have seen down in the basement (but I don't think it should be part of the closed system) is around the bottom edge of the hot water tank water has been leaking out for a couple months. Nothing pissing out or anything just residual water around the rim of the bottom plate that slowly ,makes its way to a drain on the floor (or may be slow enough that it just evaporates from the floor, I don't remember). I'll try to take a picture of it if it hasn't stopped by now since the tank is basically empty.

As I said, I'm not sure if that is part of the closed system or not, but when I did drain water from the hot water return like I stated in my last post the boiler pressure did drop. So actually never mind, I guess it is part of the closed system.

My thinking now is, that slow drop in pressure over the past couple months as well as the PRV being somewhat stuck wasn't refilling the pressure like it was supposed too. Does that sound plausible?

As I said earlier the PRV screen crumbled when I opened up the clean out. Can I replace just the screen or should I just get a whole new valve (if it is in fact stuck anyway)?

Thanks
 
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Old 08-10-13, 12:50 PM
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Here are some pics. After looking closer, it's pretty clear where the leak in the hot water tank is actually coming from, not the bottom plate like I thought but the brass nipple. I'll work on taping/doping it tomorrow.

My best judgement was telling me it was the bottom most solenoid (I mean the three silver boxes) that was making the most noise, clicking open and shut. It also seemed to be that solenoid making the loud whistling sound. It sounded just like a train...

I'm a little disappointed I had to work today and run some errands, I missed calling Ferguson's to see if they carried the B&G FB-38TU valve.

edit: I didn't realize attanching jpgs this way would automatically add their pictures to the thread...I'll upload them elsewhere and post links if needed

edit2: Sorry the pic on the leak wasn't more clear, but it's from that brass nipple that is right there.
 
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Old 08-10-13, 02:05 PM
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am I correct in assuming my hot water is the only reason for it to kick on in the summer?
It depends... most likely yes, you are correct. BUT, some boilers are set up (perhaps unwisely) to operate as a 'warm start' whereby they will maintain a minimum water temperature even if the water heater is not calling. I don't believe that yours is a warm start boiler.

My thinking now is, that slow drop in pressure over the past couple months as well as the PRV being somewhat stuck wasn't refilling the pressure like it was supposed too. Does that sound plausible?
Yes, plausible. The leak you have been seeing could well be on the piping to and from the boiler, and leaking inside the water heater jacket where the pipes connect to the coil inside.

Can I replace just the screen or should I just get a whole new valve (if it is in fact stuck anyway)?
You could just replace the screen if you can find one. Chances of that are pretty slim actually. Most times the valve is replaced.

My best judgement was telling me it was the bottom most solenoid (I mean the three silver boxes) that was making the most noise, clicking open and shut. It also seemed to be that solenoid making the loud whistling sound. It sounded just like a train...
Those are your ZONE VALVES. If they were whistiling, when you refilled the boiler you probably only pressurized it. There may have been a lot of air still in the system. You MIGHT have been making STEAM... and that may be what you were hearing whistling through the valves... it's a WAG, but possible.

Nothing should have been clicking open and shut... you probably have multiple compounded problems there.
 
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Old 08-10-13, 02:13 PM
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Thanks for all the information, as I said I missed my opportunity to possibly pick up a new valve locally this weekend so there might not be much I can do until Monday. When I do those first couple fixes I'll try to post a video of it filling up.

Thanks again.
 
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Old 08-10-13, 02:19 PM
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Apparantly from what I see is the indirect is leaking and the reason you are probably losing pressure in the boiler... That indirect is a jacket type I believe with the boiler water circulating on the outside. If its leaking from the jacket then it needs to be replace...

You can check the date on the indirect and see if its under warranty...

To test this is to leave boiler electric off....Open fill valve to fil lthe boiler and watch the gauge.... It should rise to around 12-15psi.... then shut off the water feed....

Open up this zone valve. There is a lever underneath it... Move lever over and lock it behind the little tab....Its spring loaded lever so it will take a little force...


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Then monitor the pressure.... Let us know if it drops and how long... and if it coincided with the leak at the indirect water heater...

Let us know...
 
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Old 08-10-13, 02:19 PM
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I believe there are unions on top of the water heater - one for each pipe connected to the heater. Check to be sure the union nuts are tight. If they leak, the water will run into the insulation between the tank and the lagging around the tank, and seep out through the lower penetrations through the lagging or the bottom.

This happened to me, and I thought for sure my water heater tank itself was leaking. Somehow, with the thermal cycling, the unions had become slightly loose.

You can try tightening the drain valve tee to make sure it is not leaking. You will first have to disconnect the pipe from the tee.
 
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Old 08-10-13, 02:41 PM
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Thanks lawrosa, until I get a new pressure reducing fill valve (or screen) should I attempt to fill the system? The screen isn't in that bad of shape actually. A bottom quarter of it is missing but it's mostly intact. Is it safe to put it back?

I also see this watts one (Watts 1/2 in. Brass FPT Feed-Pressure Regulator-1156F at The Home Depot) at home depot. I don't see it saying 12 psi anywhere but I'm assuming its made for these systems and has to be set some where close. Is it a sufficient replacement?

Weil-Mclain seems to have lifetime warranties on their indirect fired water heaters, and I think its less than 10 years old regardless. I believe it was installed by PSE&G (subcontractors?) originally.

Also the intake ball valve on the feed valve was barely cracked (open). That's just to limit the volume of water (and maybe pressure?) used to fill the boiler?
 
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Old 08-10-13, 02:45 PM
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Looks like my last post has to be reviewed by moderators (the home depot link?)...

Cool gilmorrie, thanks. I'll take a closer look at all of the upper connections and maybe try to clean the thing up a little.
 
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